biology notes for class first year

BIOLOGY NOTES FOR CLASS FIRST YEAR

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First Year Biology Notes 1

Composer: Seetal Daas Contact: [email protected] 1

Chapter-1

DEFINITION OF BIOLOGY

Biology is the study of living organisms. It is derived from Greek words.

CLASSIFICATION OF LIVING ORGANIZATION

According to the modern classification given by R.H.Whittaker in 1969, living

organisms are divided into five major kingdoms, which are:

KINGDOM MONERA

It includes all prokaryotes, unicellular organisms. For example Bacteria and Cyan

bacteria.

KINGDOM PROTOCTISTA(PROTISTA)

It includes unicellular Eukaryotic organisms, which are in between plants and

animals. e.g. Chlamydomonas, Euglena, Paramecium. etc

1. KINGDOM FUNGI It includes non-chlorophyllus multi-cellular, thallophytic organisms having cell wall.

For example all types of fungi, unicellular to multi-cellular like Mushrooms and Yeast

etc.

2. KINGDOM PLANTAE

It includes all chlorophyllus multi-cellular Eukaryotic living organisms having

cellulose cell wall. For example apple, red wood etc.

3. KINGDOM ANIMALIA

It includes all Eukaryotic multi-cellular, non-chlorophyllus organisms having no cell

wall. For example Hydra, Earthworm, Human Beings etc.

EUKARYOTIC ORGANISMS

Those organisms, which have true membranous structure in their cells, like

mitochondria, golgi bodies, endoplasmic reticulum. e.g. All plants, Higher animals.

PROKARYOTES

Those living organisms, which do not have true membranous structure in their cells.

e.g. Bacteria, Blue green algae.

PHYLETIC LINEAGE

All living organisms of today belong to a common ancestor and each specie of

organism arranged no ancestor to descendent order with rest of the group evolved

from one that immediately preceded.



BRANCHES OF BIOLOGY

1. MOLECULAR BIOLOGY

It is a recent branch of biological science that deals with the structure and function of

the molecules that form structure of cell and organelles that take part in the biological

processes of a living organism (Nucleic acid – Protein molecule)

2. MICRO BIOLOGY

It deals with the study of micro-organisms (viruses, bacteria, protozoan etc)

3. ENVIRONMENTAL BIOLOGY

It deals with the study of environment and its effect on organisms.

4. MARINE BIOLOGY It deals with the study of organisms inhabiting the sea an ocean, and the physical and

chemical characteristics of their environment.

5. FRESH WATER BIOLOGY It deals with the life dwelling in fresh waters, physical and chemical characteristics of

fresh water bodies affecting it.

6. PARASITOLOGY It deals with the study of parasitic organisms, their life cycles, mode of transmission

and interaction with their hosts.

7. HUMAN BIOLOGY

The branch of biology deals with all biological aspects of man regarding evolution,

anatomy physiology, health, inheritance etc.

8. SOCIAL BIOLOGY Social biology is concerned with the social interactions with in a population of a given

species, especially in human beings focuses on such issue as whether certain behavior

are inherited or culturally induced.

9. BIOTECHNOLOGY This is a very recent branch introduce in biological sciences. It deals with the use of

data and techniques of engineering and technology for the study

and solution of problems concerning living organisms particularly the human beings.

BIOLOGICAL METHOD



In order to solve the biological problems (any animal or plant disease or

environmental hazard), following steps are necessary.

1. HYPOTHESIS

An educated guess or fact regarding the biological problem.

INDUCTIVE REASONING

Isolated facts to reach a general idea that explain the biological problem.

DEDUCTIVE REASONING

Accurate experimentation, true conclusions or results regarding the biological

problems.

2. OBSERVATION/EXPERIMENTS

The given hypothesis is checked with the help of observation and experiments and

then on the basis of it a theory or rule is established.

3. THEORY

If observations and experiments come true then hypothesis is taken true, otherwise it

is rejected. Only on the basis of true hypothesis a theory is established.

4. LAW/PRINCIPLE

When theory is proved to be true under all tested circumstances then it is accepted as a

law.

MALARIA

Malaria means disease cause by bad air.

Actual Causative agent is plasmodium (Vector Female, Anopheles Mosquito)

Leveran first discover plasmodium in human R.B.C.

Ronald Ross discovered plasmodium in the stomach of female Anopheles Mosquito.

Grassi discover the complete life cycle of Plasmodium in human being and mosquito.

ANTIBIOTICS

Substances or chemicals, which are required in small quantity to inhibit the growth of

Microorganisms. The first antibiotic was penicillin discovered by Fleming. Other

examples are: Erythocin, Rythocin, Gentamycin, Ampicillin etc.

CHEMOTHERAPY

Treatment with drug or chemical.

RADIOTHERAPY



Treatment with radiations, like α, β, γ or X-rays.

HYDROPONICS

It is the science of terrestrial plants growing in aerated solutions (add CO2 under

pressure, in any liquid also known as aerated water). This technique is also known as

soil less or water culture.

ADVANTAGES

1. Control weeds and soil disease problems.

2. Area required for cultivation is minimum.

3. Can be applied on any part of the world.

4. Main purpose is to fulfill the food requirements of rapidly increasing world

population.

CLONING

Production of duplicate copies of genetic material, cells or entire multicellular living

organisms, occurring naturally in plants or animals. Duplicate copies are known as

clones.

NATURAL CLONING

Identical twin, triplet in humans.

Asexual reproduction in plants and animal.

Regeneration and wound healing.

Growth of tumor cells or cancers.

ARTIFICIAL CLONING

Cloning of human cells such as liver cells, skin cells, blood cells are quite helpful to

develop human organs in laboratories.

There are also enormous advantages of cloning in the field of medicine and

agriculture. Examples are vegetative reproduction of fruits and nuts by grafting.

Artificial cloning is also used for treating disease, production of medically significant

substances such as Insulin, growth hormones, interferon and anti-thrombin etc.

LEVEL OF BIOLOGICAL ORGANIZATION

Life is built on chemical foundation and the life of all living organisms emerges on

the level of cell. The foundation of cell is based on elements. Atoms of different

elements unite to form molecules. Living organism usually form extremely large and

complex molecules by living matter which is present in their bodies. The molecules of

living organisms are mostly composed of carbon and provide building blocks of living

matter. Mostly living matter of an organism is composed of organic molecules along

with inorganic compounds (minerals) are also associated for e.g. Human blood.



Simple organic molecules present in living organisms are sugar, glycerol and fatty

acids, amino acids, purine and pyramidines. Similar types of cells form-tissues,

similar tissues form organs, different organs coordinating with each other form system

and different systems combine to form a living organism.

Cell → Tissues → organs → System → An Individual

Biological organization can be divided into the following levels:

SUB-ATOMIC PARTICLES

“Particles that make up an atom are called sub-atomic particles”.

For e.g. electron, proton and Neutron.

ATOM

“The smallest particle of an element that retains the property of that element”.

For example: Hydrogen, carbon and oxygen etc.

MOLECULE

“The combination of similar and different atoms are called molecules”.

For example Hydrogen and oxygen combines to form water molecules.

ORGANELLE

“A structure with in a cell that performs a specific function”.

For example: Mitochondria, chloroplast etc.

CELL

“The smallest structural and functional unit of life”.

For example: A nerve cell

TISSUE

“A group of similar cells that performs a specific function”.

For example: Nervous tissue.

ORGAN

“A structure with in an organism usually compose of several tissue types that forms a

functional unit”.

For example: The brain

ORGAN SYSTEM

“Two or more organs working together in the execution of a specific bodily function”.

For example: The nervous system.



MULTICELLULAR ORGANISM

“An individual living thing composed of many cells are called Multicellular

organisms”.

For example: Pronghom antelope.

SPECIE

“A group of very similar inter breeding organisms constitutes a species”.

For example Herd of pronghom antelope.

POPULATION

“Members of same species inhabiting the same area are considered as population”.

For example: Herd of pronghom antelope.

COMMUNITY

“Population of several species living and interacting in the same area form a

community”.

For example: Snake, antelope and hawk.

ECO-SYSTEM

“A community with its environment including land, water and atmosphere, constitute

an eco-system”.

BIOSPHERE

“The part of earth inhibited by living organisms, both living and non-living

components.”

Chapter-2

BIOCHEMISRTY

Biochemistry is a branch of biology, which deals with the study of chemical

components and chemical processes in living organisms.

WATER (H2O)

MAIN CHARACTERISTICS OF WATER

Chemically it is “Dihydrogen oxide”

It is the most abundant component in living cell.

Its amount varies approximately from 70 to 90% and life activities occur in the cell

due to the presence of water.

It is a polar molecule, means that it has a very slightly negative end (the oxygen atom)

and a very slightly positive end (the hydrogen atom).

Due to its polarity, H2O molecules form hydrogen bonds.



IMPORTANT BIOLOGICAL PROPERTIES OF WATER

(1) BEST SOLVENT

Water is an excellent solvent for polar substances, when ionic substances dissolved in

water, dissociate into positive and negative ions.

Non-ionic substances, having charged groups in their molecules, are dispersed in

water.

Because of solvent property of water, almost all reactions in cells occur in aqueous

media.

(2) HIGH HEAT CAPACITY

Water has great ability of absorbing heat due to its high specific heat capacity.

The specific heat capacity of water is the number of calories required to raise the

temperature of 1g water through 1ºC.

The thermal stability plays an important role in water based protoplasm of

individual’s metabolic activities.

(3) HIGH HEAT OF VAPORIZATION

Liquid water requires higher amount of heat energy to change into vapours due to

hydrogen bonding which holds the water molecules together.

It provides cooling effect to plants when water is transpired, or to animals when water

is respired.

(4) ACT AS AMPHOTERIC MOLECULE

Water molecule acts both as acid and a base. As acid, it gives up electron to form H+

ion, while as a base, it gains electron to form OH ions.

H2O ↔ H+ + OH-

It acts as buffer and prevents changes in the pH of living body.

(5) PROTECTION

Water is an effective lubricant that provides protection against damage resulting from

friction.

It also forms a fluid cushion around organs that helps to protect them from trauma.

(6) AS REAGENT /TURGIDITY

Water acts as a reagent in many processes such as photosynthesis and hydrolysis

reactions.

It also provides turgidity to the cells.

ORGANIC COMPOUNDS



Those compounds containing carbon (other than carbonates) are called organic

compounds. E.g: carbohydrates, Proteins, Lipids and Nucleic acid.

INORGANIC COMPOUNDS

Those compounds, which are without carbon, are called inorganic compounds. E.g:

water, carbondioxide, acids , bases and salts.

MACROMOLECULES

Huge and highly organized molecules which form the structure and carry out the

activities of cells are called “Macromolecules” Macromolecules can be divided into

four major groups.

Proteins

Carbohydrates

Lipids

Nucleic acids.

MONOMERS

Macromolecules are composed of large number of low molecular weight building

blocks or subunits called “Monomers” E.g: Amino-acids (Protein).

CONDENSATION

The process by which two monomers are joined is called “Condensation”.

In this process two monomers join together when a hydroxyl(OH) group is removed

from one monomer and a hydrogen (-H) is removed from other monomer.

This type of condensation is called “Dehydration Synthesis” because water is

removed (dehydration ) and a bond is made (synthesis).

HYDROLYSIS

A process during which polymers are broken dawn into their subunits (monomers) by

the addition of H2O called “Hydrolysis “. It is just reverse of the condensation.

FUNCTIONAL GROUPS

These are particular group of atoms that behave as a unit and give organic molecules

their physical, chemical properties and solubility in aqueous solution. E.g

Methyl group (CH3-)

Hydroxyl or Alcohol group (OH-)

Carboxylic acid or Organic-acid group (COOH-)

Amino or Amine group (NH2-)

Carbonyl group (CO=)



Sulfhydryl group (SH-)

PROTEINS

These are the complex organic compounds having C, H,O and N as elements but

sometimes they contain P and S also. Due the presence of N they are called

“Nitrogenous Compounds” Proteins constitute more than 50% of dry weight of cell.

They are present in all types of cells and in all parts of the cell.

CHEMICAL COMPOSITION OF PROTEINS

Proteins are polymers of amino-acids and number of amino-acids varies from a few to

3000 or even more in different proteins.

These amino-acids are linked together by specialized bond or linkage called “peptide

linkage”

Each proteins has a unique sequence of amino-acids that gives the unique properties

to molecules.

AMINO ACID

It is the basic structural unit of proteins and all amino-acids have an “Amino group

(NH2-) and a “Carboxyl group (COOH-)” attached to the same carbon atom, also

known as “Alpha carbon”. The have the general formula as:

1. A hydrogen atom.

2. An amino (NH2) group.

3. A carboxyl group (COOH)

4. “Something else” this is the “R” group.

R

?

H2N ?C ? COOH

(Amino group) ? (Carboxylic group)

H

“R” may be a “H” as in glycine, or CH3 as in alanine, or any other group. So amino

acids mainly differ in the R-group.

POLYPEPTIDES

Amino Acids are linked together to from polypeptides of proteins. The amino group

of one amino acids may react with the carboxyl group of another releasing a molecule

of water. E.g: Glycine and analine may combine to form a dipeptiede

PEPTIDE LINKAGE/ BOND

The linkage between the hydroxyle group of carboxyl group of one amino-acid and

the hydrogen of amino-group of another amino-acid release H2O and C-N link to

form a bond called “Peptide bond”.



TYPES OF PROTEINS ON THE BASIS OF STRUCTURE

There are four basic structural levels of proteins.

(A) PRIMARY STRUCTURE

A polypeptide chain having a linear sequence of amino-acids.

Disulphide (S-S) bond is other important characteristic of the primary protein.

E.g: Insulin Polypeptide chain.

B) SECONDARY STRUCTURE

In this type polypeptide chain of amino-acids become spirally coiled.

This coiling results in the formation of a rigid and tubular structure called “Helix”

C) TERTIARY STRUCTURE

Polypeptide chain bends and folds upon it self forming a globular shape.

It is maintained by three types of bonds. Namely ionic, hydrogen and disulfide (S-S).

(D) QUATERNARY STRUCTURE

This type is usually present in highly complex proteins in which polypeptide tertiary

chains are aggregated and held together by hydrophobic interactions, hydrogen and

ionic bonds.

E.g: Haemoglobin molecule.

FUNCTIONS OF PROTEIN

They Build many Structures of the cell E.G: Plasma Membrane.

All enzymes are proteins and in this way they control the whole metabolism of the

cell.

Skin, nails, hair, feather, horn etc. contain portion called keratin.

Casein is the milk portion and ovalbumin is the egg white protein.

Collagen present in bones, cartilage, etc. is the most abundant protein in higher

vertebrates.

Protein acts as antibodies, antigens and fibrin etc.

CARBOHYDRATES

It is a group of organic compounds having carbon, oxygen and hydrogen, in which

hydrogen and oxygen are mostly found in the same ratio as in water i.e. 2:1 and thus

called “Hydrated carbons” They are found about 1% by weight and generally called

Sugars or saccharides” due to their sweet taste except polysaccharides.

CLASSIFICATION OF CARBOHYDRATES



The carbohydrates can be classified into following groups on the basis of number of

monomers.

1. Monosaccharide

2. Oligosaccharides

3. Polysaccharides.

(1) MONOSACCHARIDES

These are called “Simple Sugars”, because they can not be hydrolysed further into

simple sugars.

Their general formula is “Cn H2n On

They are white crystalline solids with sweet taste and soluble in water.

They are present in various fruits and vegetables.

E.g: Glucose, Galactose, Fructose and Ribose etc. Monosaccharide can be sub-

classified according to umber of carbon atom present in each molecule. They may be

triose, (Glycerose), tetrose (erythrose), pentose, (ribose), hexone (glucose) or heptose

(Glucoheptose) having 3,4,5 ,6 and 7 carbon atoms respectively.

(2) OLIGOSACCHARIDES

These carbohydrates yield 2to 10 monosaccharides mnolecules on hydrolysis

Disaccharides are the most common and abundant carbohydrates of oligosaccharides.

These sugars are comparatively less sweet in taste, and less soluble in water.

E.g: Maltose, Sucrose and lactose etc.

(3) POLYSACCHARIDES

These are the most complex and most abundant carbohydrates in nature.

They are of high molecular weight carbohydrate which on hydrolysis yield mainly

monosaccarides or products related to monosaccharide.

These sugars are formed by the condensation of hundreds of thousands of

monosaccharide units.

They are tasteless and only sparingly souble in H2O.

E.g: Strach, cellulose Glycogen , Dextrin Agar, pectin and Chitin etc.

FUNCTIONS OF CARBOHYDRATES

Carbohydrates are the potential source of energy.

They act as storage food molecules and also work as an excellent building, protective

and supporting structure.

They also form complex conjugated molecules.

They are needed to synthesize lubricants and are also needed to prepare the nectar in

some flowers.

LIPIDS



These are naturally occurring compounds, which are insoluble in water but soluble in

organic solvents. They contain carbon, hydrogen and oxygen like carbohydrates rate

but in much lesser ratio of oxygen than carbohydrates. These biomolecules are widely

distributed among plants and animals.

CLASSIFICATION OF LIPIDS

Following are the important groups of lipids.

1. Acylglycerol (fats and oil)

2. Waxes

3. Phospholipids.

4. Terpenoids.

(1) ACYLGLYCEROL (FATS AND OIL)

These are found in animals and plants, provide energy for different metabolic

activates and are very rich in chemical energy.

They are composed of glycerol and fatty acids. The most widely spread acylglycerol

is triacyl glycerol, also called triglycerides or natural lipids.

There are two types of acylgycerol

(A) SATURATED ACYLGLYCEROL

They contain no double bond.

They melt at higher temperature than unsatured acylglycerols.

Lipids containing saturated acylgycerol are solid and known as Saturated lipids.

E.g: Butter and Animal fat. etc.

(B) UNSATURATED ACYLGLYCEROL

They contain unsaturated fatty acids i.e they contain one or more than one double

bond between carbon atom(C=C-).

They are liquid at ordinary temperature .

They are found in plant also called “Oil”

E.g: linolin found in cotton seeds etc.

(2) WAXES

Chemically waxes are mixtures of long chain alkanes and alcohols. Ketones and esters

of long chain fathy acids

Waxes are widespread as protective coatings of fruits and leaves some insects also

secrete wax.

Waxes protect plants form water loss and abrasive damage.

They also provide water barrier for insects, birds and animals etc.

(3) PHOSPHOLIPIDS



It is most important class of lipids from biological point of view and is similar to

riacylglycerol or an oil except that one fatty acid is replaced by phosphate group.

The molecule of phospholipids consist of two ends, which are called hydrophilic

(water loving end (head) and hydrophobic (water fearing)end (Tail).

These are frequently associated with membranes and are related to vital functions

such as regulation of cell permeability and transport process.

(4) TERPENOIDS

It is large and important class of lipids containing “Isoprenoid “ unit (C5H8).

They help in oxidation reduction process, act as components of essential oils of plants

and also found in cell membrances as “cholesterol

SUB-CLASSES OF LIPIDS

1. Terpenes

2. Steroids.

3. Carotenoids.

(1) TERPENES

This group based only on “Isoprenoid” unit and they are usually volatile in nature

produce special fragrance.

Derivatives of this group are found in vitamin A and are also important constituents of

chlorophyll and cholesterol biosynthesis.

They are utilized in synthesis of “Rubber” and “Latex”, and some of these are used in

perfumes.

(2) STEROIDS

This group of Terpenoids contains 17 carbon atoms ring called “steroid nucleus”.

(3) CAROTENOIDS

They consist of fatty acid like carbon chain and usually found in plants, for example

carotene, xanthophylls etc.

NUCLEIC ACIDS

Nucleic Acids Were First Isolated In 1870 By an Austrian Physician Fridrich

Micscher from the nuclei of pus cells. These bio molecules are acidic in nature and

present in the nucleus.

TYPES OF NUCLEIC ACIDS

Nucleic acids are of two types.

1. Deoxyribonucleic acid or DNA

2. Ribonucleic acid or RNA



CHEMICAL NATURE OF NUCLEIC ACID

Nucleic acids are complex substances. They are polymers of units called nucleotides.

DNA is made up of deoxyribonucleotides, while RNA is composed of ribo

nucleotides.

STRUCTURE OF NUCLEOTIDE

Each nucleotide is made of three subunits

a) 5-carbon monosaccharide (a pentose sugar)

b) Nitrogen containing base.

c) Phosphoric acid.

(A) PENTOSE SUGAR

Pentose sugar in RNA is ribose, while in DNA it is deoxyribose.

(B) NITROGENOUS BASE

Nitrogenous bases are of two types

(I) PYRIMIDINES (SINGLE RINGED): These are cytosine (abbreviated as C),

thymine (abbreviated as T), and uracil (abbreviated as U).

(II) PURINES (DOUBLE RINGED): These are adenine (abbreviated as A) and

guanine(abbreviated as G).

C) PHOSPHORIC ACID

Phosphoric acid (H3PO4) has the ability to develop ester linkage with OH group of

pentose sugar.

FORMATION OF NUCLEOTIDE

Formation of nucleotide takes place in two steps. First the mitrogenous base combines

with pentose sugar at its first carbon to form a “Nucleoside”. In second step the

phosphoric acid combines with the 5th carbon of pentose sugar to form a

“Nucleotide”.

(A) MONONUCLEOTIDES

They exist singly in the cell or as a part of other molecules.

These are not the part of DNA or RNA and some of these have extra phosphate

groups e.g ATP.

(B) DINCULEOTIDES

These nucleotides are covalently bounded together and usually act as co-enzymes

E.g NAD (Nicotinamide dinucleotide ).



(C) POLYNUCLEOTIDES

Nucleotides are found in the nucleic acid as “Polynucleotide” and they have a variety

of role in living organisms.

They usually perform the function of transmitters of genetic information.

CONJUGATED MOLECULES

Two different molecules, belonging to different categories, usually combine together

to form “Conjugated molecules”.

These conjugated molecules are not only of structural, but also are of functional

significance.

They play an important role in regulation of gene expression.

(A) GLYCOPROTEIN AND GLYCOLIPIDS

Carbolydrates may combine with proteins to form glycoprotein or with lipids to form

glycolipid.

FUNCTIONS a) Most of cellular secretions are glycoprotein’s in nature.

b)Both glycoproteins and glycolipids are integral structural components of plasma

membranes.

(B) LIPOPROTEINS

Combination of lipids and proteins form lipoproteins.

FUNCTION

They are basic structural framework of all types of membranes in the cells.

(C) NUCLEOPROTEINS

Nucleic acids have special affinity for basic proteins . they are combined together to

form nucleoproteins.

FUNCTIONS The nucleoproteins (Histone) are present in chromosomes.

THINGS TO BE REMEMBER

Proteins-Berzelius and G.J murlder.

Lipids-Bloor in 1943.

DNA –Hereditary material.

RNA- carrier of genetic information.

rRNA – (Ribosomal RNA)- Double stranded.

Transcription- Formation of mRNA.

Translation –Formation of Proteins by ribosmes.



DIFFUSION

The movement of ions or molecules from the region of higher concentration to the

region of lower concentration is known as diffusion.

EXAMPLES

1. If a bottle of perfume is opened in a corner of a room, it can be smelt in the entire

room.

2. Leakage of gas pipes can be smelt from a farther point.

3. If we drop a KMNO4 crystal in clean water, then after sometime the

crystals will dissolve and color of water changes from colorless to purple.

FACTORS ON WHICH RATE OF DIFFUSION DEPENDS

1-SIZE Small molecules move faster than larger ones.

2-TEMPERATURE Rate of diffusion will be high at high temperatures.

3-CONCENTRATION GRADIENT

Greater the difference in concentration and shorter the distance between two regions,

greater will be the rate of diffusion.

FACILITATED DIFFUSION

Diffusion of the substances across the cell membrane through the specific carrier

proteins is known as facilitated diffusion. These membrane transport proteins are

channel proteins, receptors, cell pumps or carriers, made up of usually proteins and

don’t require energy for transport.

PASSIVE TRANSPORT

Movement of substances in and out of the cell, caused by simple kinetic motion of

molecules, doesn’t require energy of ATP is known as passive transport, e.g. Simple

diffusion and facilitated diffusion.

OSMOSIS

The movement of water molecules from the region of higher concentration to the

region of lower concentration through a semi-permeable membrane, is known as

osmosis.

TYPES OF OSMOSIS



A- ENDOSMOSIS

The movement of water molecules into the cell, when it is placed in hypotonic

solution is called as Endosmosis.

B- EXOMOSIS

The movement of water molecules out of the cell when the cell is placed in a

hypertonic solution.

ACTIVE TRANSPORT

The movement of ions or molecules across the cell membrane against the

concentration gradient i.e. from lower concentration to higher concentration with the

help of specific transport proteins in the cell membrane, at the expense of cell’s

metabolic energy – ATP is called active transport.

EXAMPLES 1. Sodium-Potassium pump in nerve cells which pump Na+ out of the nerve

cell, and K+ into the cell against the concentration gradient.

2. Cells lining the intestine can transport glucose actively from a lower

concentration in the intestinal contents to higher concentration in blood.

3. In plants phloem loading is an ex. Of active transport.

IMBIBITIONS

Adsorption of water and swelling up of hydrophilic (water loving) substances is

known as imbibitions.

HYDROPHILIC SUBSTANCES

Those which have great affinity for water are hydrophilic e.g. starch, gum,

protoplasm, cellulose, proteins, e.g. seeds swell up when placed in water.

Wrapping up of wooden framework during rainy seasons.

Dead plant cells are hydrophilic colloids.

The chemical potential of water is a quantitative expression of the free energy

associated with the water.

UNIT: Joules/mole

This term has been replaced by water potential

WATER POTENTIAL (PSI)

It is the difference between the fee energy of water molecules in pure water and

energy of water in any other system, or solution. Water potential is a relative quantity,



depends upon gravity and pressure.

Q = Q* + f (concentration) + f (pressure) + f (gravity)

Β* is standard water potential or pure water potential of valve O Mpa.

Unit : Megapascal’s – Mpa

(1 Mpa = 9.87 atmospheres)

USES

The direction of water flow across cell membrane can be determined. It is a measure

of water status of the plant.

OSMOTIC PRESSURE

The pressure exerted upon a solution to keep it in equilibrium with pure water when

the two are separated by a semi permeable membrane is known as Osmotic pressure.

It prevents the process of osmosis.

OSMOTIC POTENTIAL

The tendency of a soln to diffuse into another, when two solutions of different

concentrations are separated by a differentially permeable membrane.

It is represented by βs for pure water βs = 0

The βs decrenses as the osmotic concentration increases.

Osmotic concentration is the number of osmotic-ally active particle per unit volume.

Osmotic potential has been replaced by solute potential.

The concentration of solute particles in a solution is know as solute potential βs. It

value is always negative.

PRESSURE POTENTIAL ΒP

When a cell is placed in pure water or in aqueous solution with higher water potential

than the cell sap water follows into the vacuole by endosmosis thru cell membrane

and tonoplast. Due to this inflow of water, the tension developed by the cell wall

causes an internal hydrostatic pressure to develop, which is called as pressure

potential.

Β = βs + βp or Qp = Q – Qs

In turgid cells βp is equal and opposite to βs

TURGID CELL

When the cell is fully stretched with maximum pressure potential, the water cannot

flow into it. This condition is called turgidity and the cell is turgid.

PLASMOLYSIS



If a cell is placed in a hypertonic solution, which has more negative solute and water

potentials then water will come out of the cell, by exosmosis and protoplasm starts

separating from cell wall leaving a gap between cell wall and cell membrane. This

withdrawal of protoplasm from cell wall is known as plasmolysis.

The point where protoplasm just starts separating from cell wall is known as

“Incipient plasmolysis” when it is completely separated, full plasmolysis occurs.

In plasmolysis cell βp = 0 therefore βw = βs

DEPLASMOLYSIS

When a cell is placed is a hypotonic solution or pure water, there will be an inflow of

water by endosmosis. Protoplasm starts expanding and presses cell wall due to which

pressure potential develops and water potential becomes less negative. This swelling

of cell is known as deplasmolysis.

WATER AND MINERALS UPTAKE BY ROOTS

1. Absorption of water and mineral salts takes place through root system.

2. Roots are provided with enormous number of tiny root hairs.

3. These root hairs are more in number in tap root system.

4. Roots hairs are out growths of epidermal cells.

5. Roots hairs increase the surface area for absorption.

6. Most of the absorption takes place at root tips.

7. From hairs and epidermal cells water flows thru cortex, endodermis,

pericycle and them enters xylem.

There are 3 pathways for water to enter xylem.

A- CELLULAR PATHWAY

In this route water flows through cell to cell. Water enters the root hairs or epidermal

cells down a concentration gradient: it flows through cell wall and cell membrane and

enters the adjacent cell from where water may again flow towards the deeper cells by

osmosis.

B- SYMPLAST PATHWAY

Cytoplasm of the cortical cells are interconnected by small pores in the cell wall

known as plasmodesmata.

These pores provide another way of transporting water and solutes across the plasma

membrane at root hairs.

C- APOPLAST PATHWAY

The cell walls of cortical and epidermal cells are hydrophilic and form a continuous

matrix. Soil solution flows freely through these hydrophilic walls. The movement of



soil soln.through extra cellular pathway provided by continuous matrix of cell walls is

known as “Apoplast pathway”.

Simplast and apoplast usually both occur concurrently.

Endodermis forms a waxy barriers against the flow of water and salts known as

“casparion strip”. So, water cannot enter endodermis via apoplast pathway. Symplast

is the only way to cross the barrier. Endodermal cells actively transport salts to

pericycle resulting in high osmotic potential which causes inflow of water by osmosis

salts. Form pericycle water flows in to xylem via both symplast and apoplast

pathways.

TRANSPIRATION

The loss of water in the form of vapours from aerial parts of the plant is called

transpiration.

TYPES OF TRANSPIRATION

Following are the three types of transpiration.

A- STOMATAL TRANSPIRATION

It is a type of transpiration in which the water vapours escape through the stomata.

90% of the total transpiration occurs thru this method. In isobilateral leaves the

stomata are present in both upper and lower epidermis e.g. lily and maize leaves. In

dorsiventral leaves, the stomata are only confined to lower epidermis e.g. Brassica and

sunflower.

B- CUTICULAR TRANSPIRATION

The loss of water in the form of vapours through the cuticle of leaves is called

Cuticular Transpiration. About 5-7% of total transpiration takes place thru this route

cuticle is a waxy layer which covers the leaves and tis is not completely impermeable

to water.

C- LENTICULAR TRANSPIRATION

It is the loss of water vapours through lenticles present in the stems of dicot plants.

Lecticles are aerating pores present in the bark formed as a result of secondary

growth. It accounts for only 1-2% of total transpiration.

MECHANISM OF STOMATAL RESPIRATION

STRUCTURE OF STOMATA

Stomata are microscopic pores present in the epidermis of leaves and herbaceous

stems. Number of stomata are variable in different leaves and depend upon the

availability of water and climate of the region. Each stomata is surrounded by 2



specialized epidermal cells, as guard cells, they are bean shaped or kidney shaped and

unlike other epidermal cells, they contain chlorophyll, hence perform photo-synthesis.

The inner wall of guard cell is thick while the outer wall is thin and elastic. This

structural difference is important for opening and closing of stomata.

STAGES OF TRANSPIRATION

There are two processes involved in stomata transpiration.

+ EVAPORATION

In the first step, water evaporates from the wet surfaces of turgid mesophyll cells and

collected in the intercellular air spaces.

+ DIFFUSION

In this stage water vapours diffuse out from intercellular spaces where they are in

higher concentration to the outer atmosphere where they are in lower concentration

through the stomata.

MECHANISM OF OPENING AND CLOSING OF STOMATA

The opening and closing of stomata depends upon the turgidity of guard cells, which

is due to increase or decrease in the osmotic potential of the guard cells. When water

enters the guard cells by osmosis, they swell up. Since their outer walls are thin and

elastic, they stretch and bulge out. The inner thick walls cannot stretch and so arch in

and become crescent shaped thus the gap between the two guard cells widens, opening

the stomata when the guard cell lose water, they become flaccid and the inner wall of

two guard cells meet each other, closing the stomata.

Generally the stomata remain open during day time and close at night. Thus light

appears as the primary factor which control the opening and closing of stomata.

FACTORS REGULATING OPENING AND CLOSING OF STOMATA

There are two main factors which greatly influence the opening and closing of

stomata these are

1- LIGHT

In the presence of light, chlorophyll containing guard cells synthesize sugars which is

turn increase the osmotic potential of guard cells. This increase Qs results in

endosmosis and ultimately to turgidity. While in darkness these guard cells consume

carbohydrates (sugars) by respiration for energy production or transported to other

neighbouring cells for respiration and different purposes. This decreases the osmotic

potential of guard cells leading to flaccidity because of exomosis of water.

2- CONCENTRATION OF K+ IONS



Turgidity of guard cells of many plants is regulated by K+ ion concentration. During

daytime, guard cells actively transport K+ions into them from neighbouring cells.

Accumulation of K+ ions lowers the water potential of guard cells. This causes on

inflow of water by endosmosis from epidermal cells. During night when they lose K+

ion, water potential increases. Water flows out of the guard cells by exosmosis

causing them to become flaccid which result in closure of pore.

FACTORS AFFECTING TRANSPIRATION

Rate of transpiration is very important for a plant because transpiration stream is

necessary to distribute dissolved mineral salts through out the plants. Water is

transported to photosynthesizing cells of leaves. Transpiration is also very important

as it cools the plant. This is especially important in higher temperatures. If the rate of

transpiration is very high, there would be much loss of water from the plant. So at

high temperatures the stomata almost close and reduction in the rate of transpiration is

effected. This stops witting of the leaves and of herbaceous stems of plants.

Following are some important factors which affect the rate of transpiration.

1. LIGHT

Light affects the transpiration in two ways:

a. Light regulates the opening and closing of stomata. During sunshine the stomata are

open, losing water vapours thus rate of transpiration is high and during night, the

stomata are closed, so the rate of transpiration is low.

b. Greater intensity of light, increases the temperature and warms the leaf, so leaves

lose heat by evaporating water molecules to cool themselves.

2. TEMPERATURE

Plants transpire more rapidly at higher temperature than at low. Rise in temperature

has two effects:

i. It increases kinetic energy of water molecules, which results in rapid evaporation of

water and decreases the rate of transpiration.

ii. High temperature reduces the humidity of surrounding air. Due to this, evaporation

from surfaces of mesophyll cells increase and hence rate of transpiration.

3. WIND

The air in motion is called wind. The area around the stomata is saturated with water

vapours due to transpiration. During high velocity wind the area around leaves is

quickly replaced by fresh drier air which increases diffusion of water molecules from

air spaces to outside atmosphere and increases the rate of transpiration.



When air is still, the rate of diffusion of water molecules is reduced and the rate of

transpiration is also reduced.

4. HUMIDITY

When air is dry, the rate of diffusion of water molecules, from the surfaces of

mesophyll cells, air spaces and through stomata, to outside the leaf increases. So more

water is lost, increasing the rate of transpiration.

In humid air, the diffusion of water molecules is reduced. This decreases the rate of

transpiration.

5. SOIL WATER

A plant can’t continue to transpire rapidly if its moisture loss is not made up by

absorption of fresh supplies of water from the soil. When absorption of water by roots

fails to keep up with rate of transpiration, loss of turgor occurs and wilting of leaf

takes place.

DISADVANTAGES OF TRANSPIRATION

1. Transpiration is said to be necessary evil because it is an inevitable, but potentially

harmful, consequence of the existence of wet cell surfaces from which evaporation

occurs.

2. High rate of transpiration causes water deficiency and thus the excessive

transpiration leads to wilting and death of plants.

3. There is good evidence that even mild water deficiency results in reduced growth

rate of plants.

4. Excessive transpiration effects the protein synthesis, sugar synthesis and other

metabolic activities of plants.

ADVANTAGES OF TRANSPIRATION

1. Water is conducted in most parts of plants due to transpiration pull or ascent of sap.

2. It causes absorption of water and minerals from the soil.

3. Minerals dissolved in water are conducted throughout the plant body by

transpiration stream.

4. Evaporation of water from the exposed surface of cells of leaves has cooling effect

on plant.

5. Excess water is removed.

6. Wet surface of leaves allow gaseous exchange.

GUTTATION

It is the loss of water in the form of droplets from the ends of large leaf-veins. It take

place through special openings called hydathodes.



DIFFERENCES BETWEEN TRANSPIRATION AND GUTTATION

TRANSPIRATION

Water escapes in the form of wapours.

Escape water is pure and does not contain solutes.

It takes place through stomata, and cuticle.

It is regulated by stomata.

Normally takes place in light

GUTTATION

Water escapes as liquid.

Escaped water contain solutes.

It takes place through hydathodes and end of veins.

It is not a regulated process.

Takes place at night.

TRANSLOCATION OF ORGANIC SOLUTES

Transport of organic products of photosynthesis, like sugars from mature leaves to the

growing and storage organs in plants is called translocation. This movement of photo

assimilates and other organic materials takes place via the phloem and is therefore

called “Phloem Translocation.”

The phloem is generally found on the outer side of xylem and constitutes the bark.

The cells of phloem that take part in phloem translocation are called sieve elements.

Phloem tissue also contains companion cells, parenchyma cells, fibers like sclereids

latex containing cells. But only sieve tube cells are directly involved in tansport of

organic solutes.

SOURCE TO SINK MOVEMENT

The translocation of photosynthesis always takes place from source to sink tissues,

therefore, the phloem transport is also referred as “source to sink movement.”

SOURCE

The part o plant which forms the sugars or photoynthates is known as source. For

example Mature Leaves.

SINK

Sinks are the areas of active metabolism or storage of food e.g: Roots, Tubers

developing fruits, immature leaves, growing tips of roots and shoots. Some source and

sinks are interconvertible during the process of development of plants. For example:



developing and mature leaves, developing and germinating seeds, root of sugar beets

etc.

MUNCH HYPOTHESIS (MECHANISM OF PHLOEM TRANSLOCATION)

Phloem translocation is mainly explained by a theory called the “Pressure flow

hypothesis” proposed by Ernest munch in 1930 which explains the steps involved in

the movement of photosynthates from mesophyll chloroplasts to the sieve elements of

phloem of mature leaves.

STEPS

The following steps explain flow theory:

1. The glucose formed during photosynthesis in mesophyll cells, is used in respiration

or converted into non-reducing sugar i.e. sucrose.

2. the sucrose is actively transported to bundle sheath cells and then to companion cell

of the nearest smallest vein in the leaf. This is called “short distance transport”

because solutes cover only a distance of two or three cells.

3. Sucrose diffuse into sieve tube cell or sieve elements by symplast pathway or

apoplast pathway. This is called phloem loading, this raises the conc. of sugars in

sieve elements, which causes osmosis of water from nearby xylem in the leaf. It

causes an increase in the hydrostatic pressure or tugor pressure.

4. The increase hydrostatic pressure moves the sucrose and other substances in the

sieve tube cells, and moves to sinks. The photo-assimilates (sugars etc) can be moved

a long distance i.e. of several meters, therefore this is known as “Long distance

transport.”

5. In the sink tissues, present at the other end of pathway, sugars are delivered by

phloem by an active process called “Phloem Unloading.” It produces a low osmotic

pressure in sieve elements of sink, as a result of this water potential begins to rise in

the phloem and causes an exosmosis of water molecules from the sieve tubes. This

causes a decrease in turgor pressure of the sieve tubes (phloem).

6. The presence of sieve plates in the sieve elements greatly increases the resistance

along the pathway and results in the generation and maintenance of a substantial

pressure gradient in the sieve elements between source and sink. The sieve elements

contents are physically pushed along the traslocation pathway by bulk flow, much like

water flowing through a garden house.

SIGNIFICANCE OF TRANSLOCATION



1. Food can be formed or stored as in sugar beet’s root or stem of sugar cane.

2. Sucrose is transported to sink where it is converted to glucose and used as energy.

3. Productivity of crop can be increased by accumulation of photo-synthates in edible

sink tissues like cereal grains, pulses, ground nuts etc.

4. Fruit is forme by this process e.g. Apples, Mango etc.

ASCENT OF SAP

The upward movement of water and dissolved mineral salts from the roots to the

leaves agains the downward pull of gravity is known as “Ascent of Sap.”

PATH OF MOVEMENT

The distance traveled by water is small and easy in plans like herbs and shrubs and

longest in tall trees like pinus, red wood, eucalyptus etc. For transport different tissues

of xylem is used for conduction of water in different plants. These are open ended

cells called “Vessels” and porous cells called “tracheids” (Fig. From book).

A. VESSELS

1. These are thick walled tube like structures which extend through several feet of

xylem tissue.

2. They range in diameter from 20μm to 70μm.

3. Their walls are lignified and perforated by pits. At the pit, cell wall is only made up

of cellulose. Pits of adjacent cells match up with each other, so that their cavities are

interconnected.

4. Xylem vessels arise from cylindrical cells, which placed end to end. They die at

maturity forming a continuous duct, providing a channel for long-distance transport of

water.

5. Rate of flow of water is 10 times faster than tracheids.

OCCURANCE

VESSELS are mostly found in Angiospermic plants.

B. TRACHEIDS

1. These are individual cells about 30μm in diameter. They are several mm long and

tapered.

2. Like vessels, they are also dead, made up of thick lignified walls.

3. Their walls are perforated by small pits, which are of two types, simple and

bordered.

4. The Tracheids are connected by pits and forming a long channel for conduction of

water.



OCCURANCE

In Ferns and Conifers.

MECHANISM OF ASCENT OF SAP

Water and dissolved mineral salts present in xylem, flow in upward direction at the

rate of 15m/hour. Xylem sap ascends because of two reasons:

1. Push from below – Root Pressure Theory

2. Pull from above – Dixon’s Theory

1. ROOT PRESSURE THEORY

According to Stephen Hales:

“The force which is responsible for the upward movement of water molecules in

xylem is by the pushing effect from below (i.e. roots) and is known as “Root

Pressure.” Root Pressure is created by active secretion of sals and other solutes from

the other cells into xylem sap.

This lowers the water potential of xylem sap. Water enters by osmosis, thus increasing

the level of sap. Water also take apoplast or symplast pathway to enter the xylem

cells, this increased level causes a pressure effect in xylem and pushes the water

upwards.

OBJECTIONS/FAILURE OF THEORY

1. This force is unable to push water in tall plants.

2. It is seasonal.

3. Completely absent from Cycads and Conifers, so how they transfer water.

4. When a cut shoot is placed in water, the water rises in shoots although roots are

absent.

5. It is also present in plant which do not have well developed root system.

2. TRANSPIRATION PULL (DIXON’S THEORY) OR ADHESION-

COHESION-TENSION THEORY

Dixon and Jolly proposed this theory for ascent of sap. It provides a reasonable

explanation of flow of water and minerals from the roots to leaves of plants. It

depends on:

ADHESION Adhesion is the sticking together of molecules of different kinds. Water molecules

adhere to the cell walls of xylem cells, so that the column of water in xylem tissue

doesn’t break. The cellulose of cell wall has great affinity for water, which helps in

the process.



COHESION Cohesion is the attraction among molecules of same kind, which holds water

molecules together, forming a solid chain-like column within the xylem tubes.

Extensive hydrogen bonding in water gives rise to property of cohesion. The

molecules of water in xylem tube form a continuous column.

TRANSPIRATION PULL

The loss of water from the aerial parts of the plant especially through stomata of

leaves is called transpiration.

During daytime the leaf after absorbing sunlight, raising its temperature starts

transpiration. When a leaf transpires, the water potential of its mesophyll cells drop.

This drop causes water to move by osmosis from the xylem cells of leaf into

dehydrating mesophyll cells.

The water molecules leaving the xylem are attached to other water molecules of tube

by H-bonding.

Therefore, when one water molecules moves up the xylem, the process continues all

the way to the root, where water is pulled from the xylem cells, i.e. tracheids or

vessels.

Due to this pulling force or transpiration pull, water in xylem is placed under tension

which is transmitted to root through vessels. Tension is due to H-bonding and strong

cohesive forces between water molecules, and is strong enough to pull water up to

200 meters or even more.

ASCENT OF SAP IS SOLAR POWERED

To transport water over a long distance, plants do not use their metabolic energy or

ATPs. It is done only by forces like adhesion, cohesion, evaporation and presence of

sunlight. Thus ascent of sap is “Solar Powered.”

SIGNIFICANCE OF ASCENT OF SAP

Water can be transported to the different parts of the plant.

Transpiration is regulated.

Food is formed in presence of water.

Photosynthesis requires water.

Salts and minerals are also absorbed along water by roots.

CARDIAC CYCLE

Sequence of events which take pace during completion of one heart beat is called

“Cardiac Cycle”



PHASES

(I) DIASTOLE

It is resting period of heart chambers.

II) SYSTOLE

During which heart’s chambers contract. In cardiac cycle, blood is circulated in whole

body.

TYPES OF CIRCULATION

PULMONARY CIRCULATION

In pulmonary circulation following events take place.

RT. ATRIAL SYSTOL

First the blood from whole systems of body, except lungs enter in right Atrium

through superior and Inferior vena cavae into the right atrium by atiral systole, blood

comes into right ventricle from right atrium via Tricuspid valve.

RT. VENTRICLE SYSTOLE

After coming of blood into the Rt. Ventricle, it goes to the lungs via pulmonary trunk

by ventricular systole, for oxygenation of blood by passing through pulmonary valve.

SYSTEMIC CIRCULATION

In systemic circulation, following events take place.

LEFT ATRIAL SYSTOLE

When oxygenated blood comes into left atrium, then left atrial sytole causes blood to

enter left ventricle through bicuspid valve

LEFT VENTRICULAR SYSTOLE

When blood reaches here it sends into aorta through aortic valve to provide blood to

body systems.

CARDIAC OUTPUT

The blood volume pump per minute by left ventricle into the systemic circulation

HEART BEAT

The contraction of heart chambers are known heart beat which are regular, rhythmic.

Ventricular systole is LUB

Ventricular diastole is DUB

TIME FOR HEART BEAT

0.8 sec is time for one heart beat.



CONDUCTING SYSTEM OF HEART

It consists of

1.AV-NODE

2.SA-NODE

3)AV-BUNDLE

4) PURKINJI FIBERS.

1. SA-NODE

SA NODE found near upper end of superior vena cava in RT. atrium

PARTS

1. Specialized cardiac Muscles.

2. Autonomic Nerve endings.

FUNCTIONS

It Initiates the contraction of heart chambers through impulses & also transmit to AV

node.

2. AV- NODE

It is found in lower end of RT. Atrium. Structurally it is smilar to SA-NODE

FUNCTION

It transmit nerve impulses to ventricles for contraction rhythmically.

3. AV-BUNDLE

AV BUNDLE are the fibers originate from AV node. The bundle divided into Right

AV bundle, Left AV bundle

FUNCTION

It transmit nerve impulses to ventricles.

4. PURKINJI FIBERS

AV bundles red divided into small fibres which penetrate the ventricle wall also

known as purkinji fibers / Bundle of His small thin fibers.

LEUKEMIA

DEFINATION

“The malignant disorder of increase number of abnormal leucocytes in blood.”

CAUSE

The cause of leukemia is unknown.



FACTORS

Factors associated with leukemia are

Ionizing Radiation

Cytotoxic drugs.

Retroviruses.

Genetic

EFFECTS OF DISEASE

In result of leukemia, normal leucocytes counts become less.

This is progressive, and fatal condition which leads to heamorrhage or infection

THALASSEMIA

DEFINITION

“Genetically impaired globin chains formation leads to impaired or defected

formation of hemoglobin.”

GENETIC DISEASE

Thalassemia is a genetic disorder, it may be

1. Hetrozygous /Mild thalassemia:

2. Homozygous.

TYPE

BETA – Thalassemia

α – Thalassemia

BETA-THALASSEMIA

When globin chain is impaired or defected. It is most common one.

ALPHA-THALASSEMIA

when α-thalassemia globin chain of (HB) hemoglobin is defected.

KINDS OF THALASSEMIA

THALASSEMIA MINOR

When thalassemia is of heterozygous type with mild anemia.

THALASSEMIA MAJOR

When thalassemia is of homozygous type with profound hypochromic anemia. It is

more common in children & results with enlargement of kidney.

REMEDY

The only remedy is transfusion of blood at regular intervals.

CVD CARDIOVASCULAR DISEASE

Diseases of heart, blood vessels and blood circulation are generally term as CVD.



ATHEROSCLEROSIS

The disease of arterial wall with lose of elasticity, thickness of inner wall causing

narrowing of lumen, results in impairing of blood flow.

ATHEROMATOUS PLAQUES

The narrowing is due to formation of fatty lesions called atheromatous plaque in inner

lining of arteries.

COMPONENTS OF PLAQUE

These plaques consist of

LDL-LOW DENSITY LIPO PROTEINS

DECAYING MUSCLES CELLS

FIBROUS TISSUE

PLATELETES

CLUMP OF BLOOD

CAUSES

Smoking, Hypertension, Obesity, Diabetes (Severe), family history of arterial disease

EFFECTS

Atherosclerosis produces no symptoms until the damage to artery is so severe that it

restricts blood flow.

ANGINA PECTORIS

If blood flow to heart muscles is restricted causes (cell damage) necrosis called angina

pectoris. Pain in chest, arm, or jaws usually during exercise.

THROMBUS FORMATION

The formation of blood clot with in the intact blood vessel initiated by atheromatous

plaque.

REASON FOR THROMBUS FORMATION

Due to formation athromatous plaque loss of elasticity, intact blood vessel get

destroyed, blood from vessel wall comes out & later change to blood clot and blocks

the lumen of small arteries.

RESULT OF THROMBUS FORMATION

Initially thrombus block the lumen partially result in decrease blood flow to organs &

leading to impairment of physiology of organs. Later on, thrombus blocks the lumen

completely so due to complete loss of blood supply, cells damage occur.

CORONARY THROMBOSIS



Type of thrombosis when narrowing of lumen occurs in coronary blood vessels due to

formation of clot.

EFFECT

Occulsion of coronary atery causes myocardial infarction and heart attack.

HEAMORRHAGE

The escaping of blood from intact blood vessels.

STROKE

Most dangerous type of heamorrhage is that of brain which results in paralysis or

strokes.

HAEMATOMA

The accumalation of blood in interstitial spaces known as haematoma.

This will lead to edema.

STROKE

DEFINITION

The damage to the part of brain caused by, restriction in blood supply or leakage of

blood outside the vessels.

CHARACTERISTICS

Impairment of sensation, movement & function controlled by damage part of brain.

CAUSES

Hypertension

Atherosclerosis

HEMIPLEGIA

Damage to any, one cerebral hemisphere can cause weakness or paralyses of one side

of body called hemiplegia

PRECAUTIONARY MEASURES

Blood pressure should be with in normal range through proper diet. Salt should be

used in less quantities exercise should be the regular habit. Smoking must be avoided.

Person life should be free of worries.

BLOOD VESSELS

DEFINITION

“The closed vessels or tubes through which transporting medium or blood circulate

with in body called “blood vessels”.

TYPES OF BLOOD VESSELS

1. Arteries.



2. Capillaries.

3. Veins.

ARTERIES

DEFINITION

Thick walled blood vessels which carry blood from heart to the organs of body.

LAYERS

It consists of three layers.

1. Tunica Externa/ Adventitia

2. Tunica Media

3. Tunica Intima

1-TUNICA EXTERNA

It is thin but tough layer, having abundant amount of collagen fibers. It is outer most

layer.

2-TUNICA MEDIA

The middle layer has smooth muscle fibers & elastin fibers. It is the thickest layer.

3-TUNICA INTIMA

It consists of squamous endothelium.

LUMEN

Thick walled vessels & having smaller lumen than that of veins except arteries of

brain & related to cranium having large lumen.

SEMILUNAR VALVES

They are not present in arteries.

BRANCHES – DIVISIONS

Aorta divides into large arteries, large arteries into smaller arteries, smaller arteries

into arterioles, then they give rise to capillary.

At arteriole level, small sphincters are present which are known as PRE-CAPILLARY

SPHINCTER.

SPHINCTER

FUNCTION

They are for regulating the diastolic pressure.

CHARACTERSTICS

Arteries are elastic so during systolic pressure, they do not rupture and dilate.

During ceasement/ stopage of systolic pressure of heart, arteries contract & supply

even flow of blood.



The arteries carry oxygenated blood except pulmonary arteries.

VEINS

DEFINITION

The thin walled blood vessels that drian blood from body parts/organs into heart

called veins.

LAYERS

Tunica Externa

Tunica Media

Tunica Intima

1. TUNICA EXTERNA

Thickest layer in veins. It contains collagen, elastin and smooth muscles cells.

2. TUNICA MEDIA

Not thicker as that of arteries. Elastic tissues and small smooth muscle.

3. TUNICA INTIMA

Contains endothelial cells layer.

LUMEN

It has large lumen and thin wall.

SEMILUNAR VALVES

They are present in veins to prevent back flow of blood in the influence of gravity.

TRIBUTARIES

Veninules -> small veins -> large veins -> vena cava.

BLOOD PRESSURE

In veins blood pressure is low and are non pulsatile.

CHARACTERISTICS

The blood flows slowly and smoothly in veins. Veins are superficial and collapse

when empty.

CAPILARIES

The intimate microscopic closed channels of both arterial & veinous interconnected

network is called capillaries.

DIAMETER

Capillaries are extremely narrow in diameter of about 7-10 μ.

LAYERS

Capillaries are thin walled vessels & contains single layer of endothelium which

offers small resistance in transport of material across the capillary wall.



FUNCTION

Through diffusion and active transport of oxygen is transported to tissues & CO2 to

capillaries. Nitrogenous waste is filtered through the capillaries into excretory tubules.

BLUE BABIES (CYANOSIS)

Blue baby is a layman terminology. In medical science it is known as cyanosis.

DEFINITION

The term cyanosis” means the blueish discolouration of the skin & mucous membrane

due to excessive cone of reduced (deoxygenated haemoglobin) in the blood & it

appears when reduced Hb conc in capillaries is more than 5 gm/dl of blood. The

reduced Hb has an intense dark blue purple colour that is transmitted through the skin.

MOST COMMON CAUSE OF CYANOSIS

Although there are various other causes of cyanosis but the most common cause is

CONGENITAL CYANOTIC HEART DISEASE.

BASIC CAUSE OF CYANOSIS

In congenital heart diseases, there is an abnormal connection b/w right and left side of

heart, which permits the large amount of unoxygenated venous blood to bypass the

pulmonary capillaries & dilute the oxygenated blood in systemic arteries i.e RIGHT

TO LEFT SHUNT, which results in cyanosis.

SOME EXAMPLES OF CONGENITAL HEART DISEASES

Some congenital heart diseases which are responsible for the abnormal connection

between right and left sides of heart are as follows.

ATRIAL SEPTUM DEFECT (ASD)

VENTRICULAR SETPUM DEFECT (VSD)

PERSISTANT DUCTUS ARTEROSUS

In all these conditions, blood begins to flow from the aorta (left side) into pulmonary

arteries (right side) & the people donot show cyanosis until late in life when heart fails

or lungs become congested.

TETRALOGY OF FALLOT (RIGHT –TO-LEFT SHUNT)

It is the most common cause of cyanosis or blue baby in which aorta originates from

right ventricles rather than left & receives deoxygenated blood.

HUMAN HEART

INTRODUCTION

Heart, the most powerful organ in the circulatory system is conical, hollow &

muscular organ, situated in middle mediastinum.



POSITION OF HEART

Heart lies in the thoracic cavity between the lungs slightly towards left, enclosed with

in ribcage with the sternum in front & vertebral column behind.

SIZE & WEIGHT

The heart measures about 3 ½ Inches & weighs about 300 gm in males & 250 gm in

females.

MAIN FUNCTION OF HEART

Heart works continuously like a muscular pump & pumps the blood to various parts of

the body to meet their nutritive requirements.

COVERING OF HEART PERICARDIUM

Heart is surrounded by a double layered pericarcdium. The outer layer is called

Fibrous pericardium & inner layer is called as serous pericardium.

PERICARDIAL FLUID

Fluid is secreted in b/w the two layers of pericardium which is known as pericardial

fluid.

FUNCTION

Pericardial fluid acts as LUBRICANT & reduces friction b/w heart walls &

surrounding tissues during beating of heart.

STRUCTURE OF HEART

Human heart consists of four chambers.

CHAMBERS OF HEART

1. RIGHT ATRIUM

Right Atrium is the right upper chamber of heart & acts as thin walled low pressure

pump.

OPENINGS (INLETS) OF RIGHT ATRIUM

1. Superior Vena Cava

2. Anfenior Vena Cava

3. Coronary Sinus

FUNCTION

It receives venous blood from the whole body & pump it to the right ventricle through

the right atrioventricular (tricuspid opening) valve.



2. LEFT ATRIUM

Left atrium is upper triangular chamber which is present posteriorly. It also acts as

low pressure pump.

OPENINGS (INLETS) OF LEFT ATRIUM

Two pairs of pulmonary veins.

FUNCTION

It receives oxygenated blood from the lungs through 4 pulmonary veins and pumps it

to the left ventricle through the left atrioventricular orifice (mitral or bicuspid).

3. RIGHT VENTRICLE

Right ventricle is the right lower chamber of heart, which is triangular in shape.

OPENINGS OF RIGHT VENTRICLE

Tricuspids valve

Pulmonary Aorta through pulmonary valve.

THICKNESS OF WALL

The wall of right ventricle is thinner than that of left ventricle in a ratio of 1:3

SIZE OF CAVITY

Cavity of right ventricle is broader than left because of thin muscular walls, and both

of these features are due to the fact that right ventricle has to pump the blood into

lungs only against low pressure system (i.e. pulmonary circulation).

FUNCTION

Right ventricle receives deoxygenated blood from right Atrium and pumps it to the

lungs through pulmonary aorta for oxygenation.

4. LEFT VENTRICLE

Left ventricle is the most thick walled chamber and forms the apex of heart.

OPENING OF LEFT VENTRICLE

Bicuspid or Mitral valve

Systemic Aorta through aortic valve.

THICKNESS OF WALL

The walls of left ventricle are 3 times thicker than those of right ventricle. Blood

pressure is 6 times high.

SIZE OF CAVITY

The cavity of left ventricle is narrower than the right ventricle because of more

muscular walls. It is due to the fact that left ventricle has to pump the blood to the

entire body against high pressure system (Systemic Circulation).



FUNCTION

It receives oxygenated blood from left atrium & pumps it into the aorta.

INTERNAL STRUCTURE OF VENTRLES

Interior of ventricles show two parts

1. Rough in flowing part

2. Smooth out flowing part

1. ROUGH PART

TRABECULAE CARNEAE

Inflowing part of each ventricle is rough due to presence of muscular ridges called as

Trabeculae carneae.

2. SMOOTH PART

Out flowing part of each ventricle is smooth which gives origin to pulmonary trunk in

right ventricle & Ascending Aorta in left ventricle.

PAPILLARY MUSCLES

Papillary muscles are the type of Trabeculae carneae being attached by their bases to

ventricular walls, & their apices are connected to, the cusps of valves through chorda

tendinae.

CHORDA TENDINAE:

These are delicate fibrous chords, which connect the papillary muscles to the cusps of

Atriovertritcular valves.

FUNCTION

Chorda Tendinae don’t left the valves open back into the atria when the ventricles

contract.

SEPTUM OF HEART

1. INTERATRIAL SEPTUM

Internally, the right & left atria are separated by a vertical membranous septum called

as Interatrial septum.

2. INTERVENTRICULAR SEPTUM:

The right & left verticals are also separated by a thick muscular septum called as

Interventricular septum.

3. ATRIOVENTRICULAR SEPTUM



Atria lie above & behind the ventricles & are separated from ventricles by Atrioven-

tricular septum.

HEART VALVES

Heart possesses two types of valves, which regulate the flow of blood with in the

heart.

TYPES OF HEART VALVES

1. Atrioventricular valves -> Bicuspid, Tricuspid

2. Semilunar vlaves -> Aortic valve, Pulmonary valve

1. ATRIOVENTRICULAR VALVES

INTRODUCTION

Valves, which are present in b/w the Atria & ventricles are called Atrioventricular

valves.

TYPES OF ATRIOVENTRICULAR VALVES

They are of two types.

1. Bicuspid or Mitral

2. Tricuspid.

1. BICUSPID OR MITRAL VALVE

Blood flows from left Atrium to the left ventricle through left atrioventricular on

orifice, which is guarded by bicuspid or Mitral valves.

CUSPS

It has tow (2) cusps so it is called as bicuspid.

2.TRICUSPID VALVE

Blood flows from right Atrium to the Right ventricle through right Atrioventricular

orifice, which is guarded by Tricuspid.

CUSPS

It has 3 cusps so it is called as TRICUSPID.

2. SEMILUNAR VALVES

This is the second category of heart valves, which guard the emergence of pulmonary

& systemic Aorta.

TYPES OF SEMILUNAR VALVES

It has Two Types:

1. Aortic Valve

2. Pulmonary Valve

1. AORTIC VALVE



This valve guards the Aortic orifice in left ventricle

CUSPS

It consists of 3 Semilunar cusps.

2. PULMONARY VALVE

This valve guards the pulmonary orifice in right ventricle.

CUSPS

It also consists of 3 semi lunar cusps.

FUNCTIONS OF VALVES

Heart valves maintain unidirectional flow of the blood & prevents its regurgitation in

the opposite direction.

NUTRITION

OMNIVOROUS, i.e. It can eat any kind of organic matter. They search their food by

antennae.

TYPE OF DIGESTIVE SYSTEM

TABULAR DIGESTIVE SYSTEM, i.e. straight slightly coiled dig tube, open at both

ends, complete dig. system.

ORGANS OF DIGESTIVE SYSTEM

+ ALIMENTARY CANAL

It is divisible into 3 parts

1. FORE GUT / STOMODAEUM

MOUTH

BUCCAL CAVITY

OESOPHAGUS

CROP

GIZZARD

2. MIDGUT / MESENTERON / VENTRICULUS

HEPATIC CAECA

3. HIND GUT / PROCTODAEUM

ILEUM

COLON

RECTUM

ANUS

+ ASSOCIATED GLAND

SALIVARY GLANDS

1.FORE GUT



MOUTH

It lies at base of pre-oval cavity which is bounded by mouth part.

LABRUM / UPPER LIP

Appendage of 3rd head segment.

MANDIBLES

Appendage of 4th head segment. They help in mastication

MAXILLAE

Appendages of 5th head segment. They pick up and bring food.

LABIUM / LOWER LIP

Appendages of 6th head segment.

BUCCAL CAVITY

The mouth opens into buccal cavity which is short and receives the common duct of

salivary glands.

Saliva cantain ‘AMYLASE’ which act upon carbohydrates.

OESOPHAGUS

Buccal cavity opens into pharynx which in turn opens into oesophagus which is a long

and thin tube lying in thorax.

CROP

It is a large thin walled and pear shaped structure meant for storing food.

GIZZARD

Crop opens into thick walled, rounded gizzard with muscular chitins lining which is

internally produced six teeth for grinding and straining the food.

2. MID-GUT

It is narrow, short and tubular portion originate from gizzard. At beginning it receives

eight hepatic caeca hanging in haemocoel (body cavity filled with white colour

blood), ending blindly but opening in gut.

ENZYMES FROM HEPATIC CAECA

They are lined by glandular cells, which secrete enzymes.

Enzymes from hepatic caeca and mid-gut flow back into crop where digestion takes

place.

ENZYMES

1. PEDTIDASES AND TRYPSIN LIKE ENZYME -> digest proteins.

2. AMYLASES -> complete digestion of starches



3. LIPASE -> digestion of fats.

Digested food form a bolus and enclosed in a thin chitinous tube secreted by

stomodael valve of gizzard. This covering is called PERITROPHIC MEMBRANE.

It is permeable to enzymes and digested food. This membrane protects the lining of

mid gut from damage by hard indigestible components of food.

Digested food is absorbed in mid gut.

3. HIND-GUT

It has a cuticular ectodermal lining.

ILEUM

Short, narrow and muscular ileum. The beginning of ileum is marked by 60-70 fine

and long, greenish yellow MALPHIGIAN TUBULES. (excretory in function)

COLON

Colon is long, wider and coiled portion of hind gut

RECTUM

Rectum is broad last part of hind gut. It absorbs H2O and conserves the much needed

H2O from undigested food before expelling out the faeces.

ANUS

Anus is the last opening of digestive system by which hind gut opens to outside.

SALIVARY GLANDS

Salivary glands are 2 in number. each present on the sides of oesophagus. Saliva

contain amylase for digestion of carbohydrates.

Chapter-3

ENZYMES(BIO-CATALYSTS)

Enzymes are bio-catalyst which speed up the chemical reactions by lowering “Energy

of activation”.

ENERGY OF ACTIVATION

Amount of energy which is required to start a chemical reaction. OR Energy required

to break a (particular covalent) bond present in reactant.

NOMENCLATURE OF ENZYMES

Enzyme is a Greek word means-En(in) and Zyme(yeast).



DISCOVERY OF ENZYME

Term “Enzyme” was coined by F.W Kuhne in 1978.

NATURE OF ENZYME

Almost all enzymes are protein in nature except few which are nitrogenous acids like

RNA-DNA(Ribozymes). Ribozymes catalyze reactions in genetic

informations.

CHARACTERISTICS OF ENZYMES

Protein in nature and are formed by living cells.

May be intracellular or extra cellular.

Remains unchanged during and after the reaction.

Speed up the rate of reaction by decreasing energy of action.

Specific in their nature.

Heat sensitive and act on particular (optimum) temp.

Each has specific substrate pH for its activity.

Action can be alter by activators and inhibitors.

CLASSIFICATION OF ENZYME (ON THE BASIS OF STRUCTURE)

Pure or Simple Enzyme consist of only protein (e.g.Amylase and Pepsin) Conjugated

or Holoenzymes: May contain a non-protein part “Prosthetic group” as well (e.g.

Phosphatase and Peptidase)

Holoenzyme = Apoenzyme + Prosthetic group

…………….(Protein part)….(Non-protein part)

CLASSIFICATION OF ENZYME (ON THE BASIS OF FUNCTIONS)

(1) OXIDOREDUCTASE Catalyze reactions in which one substrate is oxidized while other is reduced. Sub

classes are:

Dehydrogenases(convert single bond to double bond)

Oxidases (use oxygen as oxidant)

Peroxidases (use H202 as oxidant)

Hydroxylases (introduce hydroxyl group)

Oxygenases (introduce mol. Oxygen in place of double bond).

(2) TRANSFERASES Transfer one carbon group (e.g. methyl) from one substrate to another substrate.



(3) HYDROLASES Catalyze hydrolytic cleavage of C-O, C-N, C-C and P-O bonds and other single bonds

(e.g. Peptidases, Esterases, Glycosidases and Phosphatidases).

(4) LYASES

Catalyze Elimination reactions to form double bond and reversible reaction by adding

groups across double bond (e.g. Decarboxlases, Aldolases and Dehydratases).

(5) ISOMERASES They alter the structure but not the atomic composition by moving a group from one

position to another in one molecule (e.g. Epimerases, Mutases).

(6) LIGASES

Catalyze reaction in which two molecules are joined. They are also known as

synthtases.

ROLE OF ENZYME

The enzyme react with (energy rich or energy poor) molecules and forms an

intermediate complex that breaks into,

(a) Product

(b) Enzyme

(i) Substrate + Enzyme = Complex

(ii) Complex = Product + Enzyme

The equilibrium is achieved if the ratio of conc of reactants (substrate) and product

remains same.

Rate of reaction 1/µ Energy of activation

MODE OF ACTION OF ENZYMES

1- The action of enzyme depends on its chemical structure. A typical enzyme

molecule, has “3D” structure.

2- Has depression or pit for substrate (to fit in) known as “Active site”.

3- Any other site other than active site is called “Allosteric site”

There are two theories in respect of enzyme action, which are as follows.

LOCK AND KEY MODEL

Proposed by Fischer (1898) and modified by Paul Filder and D.D Woods according to

this model,

The active site of enzyme has distinct shape.

It allows few substrate to fit in (like a particular lock allows particular key to fit in)

Enzyme breaks substrate to product

FIGURE From Text Book 3.3 page #46 (The cycle of Enzyme – substrate Interaction)



INDUCE FIT MODEL

Proposed by koshland (1959), it states that

Enzyme binds with a substrate

This binding induce changes in enzyme structure

Due to this change enzyme acts and forms product

FACTORS AFFECTING ENZYME ACTIVITY

The activity of enzymes depend on following factors,

1. SUBSTRATE CONCENTRATION

Increases with increase in substrate concentration (up to a limit)

At very high concentration, activity again decreases due to saturation of enzyme with

substrate and saturation of product i.e. higher concentration of product.

2. TEMPERATURE

Increases with in temperature(up to limits)

Maximum activity at optimum temperature.

Highly active at 37?C and destroyed at 100?C

At 0?C minimum activity.

3. PH

Enzymes are pH specific i.e. work in specific pH(because of protein can act both in

acidic and basic medium.

4. WATER Enzyme activity is usually maximum (up to limits) but decrease after limits (dilution

of enzyme)

5. RADIATIONS Enzymes become inactive due to radiations (including Alpha, Beta, Gamma rays).

6. CO-ENZYME AND ACTIVATORS

Induce the enzyme activity.

THINGS TO BE REMEMBER

INHIBITORS

Substances which decreases the activity of enzymes.



COMPETITIVE INHIBITORS Inhibitor molecules which resemble the normal substrate molecule and compete for

admission into the active site. They block the substrate from entering active site.

NON-COMPETITIVE INHIBITORS

Inhibitors bind to a part of the enzymes away from the active site (Allosteric site).

This binding cause change in the enzyme molecule shape and decrease in enzyme

activity.

FEED BACK INHIBITION

Common biological control mechanism of brain in order to regulate enzyme activity.

PROSTHETIC GROUP

Non-protein part of enzyme (Co-enzyme or Co-factor)

CO-ENZYME

When prosthetic group consist of organic molecules (like FAD/NAD)

CO-FACTORS/ACTIVATORS When prosthetic group consist of inorganic molecules (like Ca++, Na+ etc).

APOENZYME

Protein part of enzyme.

RESPIRATORY ORGANS OF COCKROACH TRACHEAL SYSTEM

Cockroach has evolved a special type of invaginated respiratory system called

Tracheal system, especially adopted for terrestrial mode of life and high metabolic

rate of insects.

STRUCTURAL CONSTITUENTS OF TRACHEAL SYSTEM

1. TRACHEA

2. SPIRACLES

3. TRACHEOLES

1.TRACHEA

Tracheal system consists of number of internal tube called Trachea which are the

connection between the spiracles and tracheal fluid.

2. SPIRACLES

Laterally, trachea open outside the body through minute, slit like pores called as

spiracles.

There are 2 pairs of spiracles on lateral side of cockroach.



2 lie in thoracic segments and 8 in first abdominal segments.

3. TRACHEOLES

On the other side, trachea ramify throughout the body into fine branches or tracheols.

Tracheoles, finally end as blind, fluid filled fine branches which are attached with

cells of tissue.

Both the trachea and tracheoles are lined internally by thin layer of cuticle.

MECHANISM OF RESPIRATION “INFLOW OF OXYGEN”

The cockroach takes in air directly from the atmosphere into the trachea through

spiracles. This air diffuses directly into fluid filled tracheoles through which diffuses

into the cells of tissues. Hence the blood vascular system of cockroach is devoid of

haemoglobin.

OUTFLOW OF CARBONDIOXIDE

Removal of CO2 from cells of body is largely depended upon plasma of blood, which

takes up CO2 for its ultimate removal through body surface via the cuticle.

RESPIRATORY SYSTEM OF FISH

MAIN RESPIRATORY ORGAN

In fish, main respiratory organs are “Gills”. They are out growth of pharynx and lie

internally with in the body so that they are protected from mechanical injuries.

INTERNAL STRUCTURE OF GILLS

Each gill is highly vascularized structure. It is composed of

1. Filaments

2. Gill bar or Gill arch

3. Lamella

1. FILAMENTS

Each gill is composed of two rows of hundreds of filaments, which are arranged in V-

shape.

2. GILL BAR OR GILL ARCH

Filaments are supported by a cartilage or a long curved bone the gill bar or gill arch.

3. LAMELLA

Lamella is a plate like structure which is formed by infolding of filaments. Lamella

greatly increase the surface area of the gill. Each lamella is provided by a dense

network of capillaries.



OPERCULUM (IN BONY FISHES)

Gills are covered on each side by gill cover called “operculum”

MECHANISM OF VENTILATION

In bony fishes, ventilation is brought about by combined effect of mouth and

operculum.

Water is drawn into the mouth. It passes over the gills through pharynx and ultimately

exists at the back of operculum through open operculur valve.

Water is moved over the gills in a continuous unidirectional flow by maintaining a

lower pressure in operculur cavity than in buccopharynx cavity.

COUNTER CURRENT FLOW OF WATER AND BLOOD

Gaseous exchange is facilitated in gills due to counter current flow of H2O and blood.

In the capillaries of each lamella, blood flows in direction opposite to the movement

of water across the gill. Thus the most highly oxygenated blood is brought to water

that is just entering the gills and has even high O2 content than the blood. As the H2O

flows over the gills, gradually loosing its oxygen to the blood, it encounter the blood

that is also increasingly low in oxygen. In this way a gradient is establishment which

encourages the oxygen to move from water to blood

IMPORTANCE

Counter current flow is very effective as it enables the fish to extract upto 80–90% of

the oxygen from water that flows over the gills.

RESPIRATORY SYSTEM OF MAN

MAIN FUNCTION OF RESPIRATION

The main function of respiratory system is inflow of O2 from the atmosphere to the

body and removal of CO2 from body to the atmosphere.

COMPONENTS OF RESPIRATORY SYSTEM

(1) PAIRED LUNGS

The respiratory (gas exchange) organs.

(2) AIR PASSAGE WAYS

Which conduct the air

(3) THORACIC CAVITY

Which lodges the lungs

(4) INTERCOSTAL MUSCLES AND DIAPHRAGM

Which decreases and increase the diameters of thoracic cavity

(5) RESPIRATORY CONTROL CENTRES



Areas in brain which control the respiration.

DETAILS OF COMPONENTS

+ THORACIC CAVITY

Paired lungs with in the pleural sacs are situated in the thoracic cavity. Separating the

thoracic cavity from the abdominal cavity is a dome-shaped musculo-tendinuous

partition called as Diaphragm.

BOUNDARIES OF CAVITY

Thoracic cavity is supported by bony cage (thoracic cage) which is made up of

Sternum -> in front

Vertebral column -> at the back

12 pairs of ribs -> on each side

Ribs are supported by Intercostal muscles

FUNCTION Increase in thoracic cavity diameter is responsible for inspiration. While decrease in

diameter is responsible for expiration.

AIR PASSAGE WAYS

Air is drawn into the lungs by inter-connected system of branching ducts called as

“Respiratory tract” or “Respiratory passage ways”

Air passage ways consists of

AIR CONDUCTING ZONE(which only conducts the air)

1. Nostrils

2. Nasal Cavity

3. Pharynx (nasopharynx and oropharynx)

4. Larynx

5. Trachea

6. Bronchi

7. Bronchioles (also called terminal Branchioles)

RESPIRATORY ZONE(Where gaseous exchange takes place)

8. Respiratory Bronchioles

9. Alveolar duct

10. Alveolar sacs or alveoli

GENERAL FUNCTIONS OF CONDUCTING AIR PASSAGES

1. Conduction of air from atmosphere to the lungs

2. Humidification of inhaled dry air.

3. Warming / cooling of air to body temp.

4. The injurious particles are entrapped by mucous and removed by ciliary



movements.

5. Lymphoid tissues of pharynx provide immunological functions

6. Cartilages prevent the passages from collapse but are not present in Bronchioles

which remains expanded by same pressure that expand the alveoli.

CONDUCTING ZONE

1. NASAL CAVITY

Atmospheric air enters the respiratory tract through a pair of openings called external

nares (Nostrils), which lead separately into nasal cavity. Nasal cavity opens into naso

pharynx through posterior nares (choanae).

Nasal cavity is lined internally by Pseudostratified columnar ciliated epithelium

containing mucous secreting cells.

Hairs, sweat and sebaceous glands are also present.

SPECIALIZED FUNCTIONS

Warming of air

Humidification or moistening of air

Filteration of air with the help of hairs

All these together called as Air conditioning function of upper respiratory passages

Olfaction ( sense of smell)

2. PHARYNX

Air enters from Nasal cavity into pharynx through internal nostrils. The openings of

nostrils are guarded by soft palate. It is internally lined by Pseudostratified ciliated

epithelium, mucous glands are also present.

FUNCTION Pharynx is responsible for conduction of air as well as food

3. LARYNX (VOICE BOX)

Pharynx leads air into larynx through an opening called glottis. Glottis is guarded by

flap of tissue called epiglottis. During swallowing, soft palate and epiglottis close the

nostrils opening and glottis respectively so that food is prevented to go either into

nasal cavity or glottis. Larynx, a small chamber consists of pair of vocal cords

FUNCTION During speech, vocal cords move medially and their vibration produce sound

4. TRACHEA (WIND PIPE)



Larynx leads the air into a flexible air duct or trachea. It bears C-shaped tracheal

cartilages which keep its lumen patent during inspiration. Its internal lining is

pseudostratified columnar ciliated epithelium containing mucous secreting goblet

cells.

FUNCTION Conduction of air

Due to mucous and upward beating of cilia, any residues of dust and germs are pushed

outside the trachea towards the pharynx.

5. BRONCHI

“At its lower end, trachea bifurcates into two smaller branches called Principle

Bronchi↑ which leads the air into lung of its side. They are also supported by C-

shaped cartilage rings upto the point where they enter the lungs”.

In all areas of trachea and bronchi, not occupied by cartilage plates, the walls are

composed mainly of smooth muscles.

6. BRONCHIOLES

On entering the lungs, each bronchus divide repeatidly. As the bronchi become

smaller, U-shaped bars of cartilage are replaced by irregular plates of cartilages. The

smallest bronchi divide and give rise to Bronchioles (less than 1.5 mm in diameter).

7. TERMINAL BRONCHIOLES

Bronchioles divide and give rise to terminal bronchioles (less than 1 mm in diameter).

Walls possess no cartilages and are almost entirely the smooth muscles. These are the

smalled airways without alveoli.

RESPIRATORY ZONE

In this zone of respiratory tract, gaseous exchange between capillary blood and air

takes place.

1. RESPIRATORY BRONCHIOLES

Terminal bronchioles show delicate outpouchings from their walls, which explains the

name Respiratory Bronchioles (less than 0.5 mm in diameter). They bear the

pulmonary alveoli.

2. ALVEOLAR DUCTS AND SACS

Each respiratory bronchioles terminates at a tiny hollow sac like alveolar duct that

lead into tabular passages with numerous thin walled out pouchings called Alveolar

sacs.

3. PULMONARY ALVEOLI



The alveolar sacs consists of several alveoli openings into a single chamber. Alveoli

are the site of exchange of respiratory gases so they are considered as Respiratory

surfaces of lungs. Each alveolus is surrounded by a network of blood capillaries.

INTERNAL STRUCTURE OF ALVEOLI

The alveolar lining cells consists of

1. Type I cells

2. Type II cells

They are also called pneumocytes.

“Bifurcation of trachea is called Carina”.

TYPE I PNEUMOCYTES

Squamous shaped cells which form the epithelial lining of alveoli

TYPE II PNEUMOCYTES

Irregular and cuboidal shaped cells which secretes a substance called Surfactant

SURFACTANT

The internal area of an alveoli is provided with a thin layer of fluid called as

Surfactant secreted by type II cells.

FUNCTION OF SURFACTANT

1. It reduces the internal surface tension of alveoli which prevent it collapsing during

expiration.

2. It increases the compliance.

3. It stabilize the alveoli.

4. It also helps to keep the alveoli dry.

LUNGS

Lungs are paired, soft, spongy, elastic and highly vascularized structures, which

occupy most of thoracic cavity. In child they are pink, but with age they become dark

and mottled due to inhalation of dust.

RIGHT LUNG

Partitioned into 3 lobes by two fissures.

LEFT LUNG

Divided into 2 lobes by one fissures.

PLEURAL MEMBRANES

Each lung is enclosed by two thin membranes called as Visceral and parietal pleural

membranes.



PLEURAL CAVITY

In between the membranes there is a narrow cavity, the pleural cavity filled with

pleural fluid which acts as lubricant.

FUNCTION OF CAVITY

1. Cardinal function is to exchange gases.

2. Phagocytosis of air borne particles

3. Temperature regulation

4. Removal of water

5. Maintainence of acid-base balance (by elemination of CO2)

6. Acts as Reservoir of blood.

BREATHING

DEFINITION

“Breathing is the process of taking in (inspiration or inhalation) and giving out of air

(expiration or exhalation) from the atmosphere up to the respiratory surface and vice

versa”

TYPES OF BREATHING

There are two types of Breathing

Negative pressure Breathing

Positive pressure Breathing

NEGATIVE PRESSURE BREATHING

Normal breathing in man is termed as negative pressure breathing in which air is

drawn into the lungs due to negative pressure (decrease in pressure in thoracic cavity

in relation to atmospheric pressure).

POSITIVE PRESSURE BREATHING

“In this kind of breathing, lungs are actively inflated during inspiration under

positive pressure from cycling valve”.

EXAMPLES

Frog uses positive pressure breathing.

PHASES OF BREATHING

1. INSPIRATION OR INHALATION

2. EXPIRATION OR EXHALATION

(1) INSPIRATION



DEFINITION

“Inspiration is an energy consuming process in which air is drawn into the lungs due

to negative pressure in thoracic cavity”

MECHANISM During inspiration volume of thoracic cavity increases which creates a pressure (intra

thoracic) that sucks the air into the lungs.

INCREASE IN VOLUME OF THORACIC CAVITY

Volume of thoracic cavity increases due to

1. Inc. in Anterio-posterior diameter

2. Inc. in Vertical diamter.

INCREASE IN ANTERIO-POSTERIOR DIAMETER During contraction of external

intercostals muscle, the ribs as well as the sternum move upward and outward, which

causes the increase in anterior-posterior diameter of thoracic cavity.

INCREASE IN VERTICAL DIAMETER

Vertical diameter of thoracic cavity inc. due to Contraction (descent) of

Diaphragm which makes it flat.

As a consequence thoracic cavity enlarges and the pressure is developed inside the

thoracic cavity and ultimately in the lungs. So the air through the respiratory tract

rushes into the lungs upto the alveoli where gaseous exchange occurs.

(2)EXPIRATION

DEFINITION “It is reserve of inspiration. The passive process in which air is given out of lung due

to increased pressure in thoracic cavity is called “Expiration”

MECHANISM During expiration, elastic recoil of pulmonary alveoli and of the thoracic wall expels

the air from the lungs.

DECREASE IN VOLUME OF THORACIC CAVITY

Volume of thoracic cavity ↓ due to

1. DECREASE IN ANTERIO-POSTERIOR DIAMETER

2. DECREASE IN VERTICAL DIAMETER

(1) DECREASE IN ANTERIO-POSTERIOR DIAMETER

It is caused by relaxation of external intercostals muscles and contraction of internal

intercostals muscles which moves the ribs and sternum inward and downward.



(2) DECREASE IN VERTICAL DIAMETER

It is caused by relaxation of diapharagm which makes it dome shaped thus reducing

the volume of thoracic cavity.

As a consequence, the lungs are compressed so the air along with water vapours is

exhaled outside through respiratory passage.

CONTROL OF RATE OF BREATHING

Rate of breathing can be controlled by two modes.

VOLUNTARY CONTROL

INVOLUTARY CONTROL

VOLUNTARY CONTROL

Breathing is also under voluntary control by CEREBRAL CORTEX

EXAMPLES

We can hold our breath for short time or can breath faster and deeper at our will.

INVOLUNTARY CONTROL

Mostly, rate of breathing is controlled automatically. This is termed as Involuntary

control which is maintained by coordination of respiratory and cardio-vascular

system.

TWO MODES OF INVOLUNTARY CONTROL

A. NERVOUS CONTROL (through respiratory centers in brain)

B CHEMICAL CONTROL (through chemoreceptors)

(A) NERVOUS CONTROL

Control of rate of breathing by nervous control is through the Respiratory centers in

Medulla oblongata which are sensory to the changes in Conc. of CO2 and H+ present

in the cerebro-spiral fluid (CSF).

RESPIRATORY CENTRES IN MEDULLA

Two center are present

(1) DORSAL GROUP OF NEURONS

Medulla contains a dorsal group (Inspiratory group) of neurons responsible for

inspiration



FUNCTION

In response to increase conc. of CO2 and H+ (decreased pH), it sends impulses to the

intercostals muscles to increase the breathing rate

(2) VENTRAL GROUP OF NEURONS

Another area in the medulla is ventral (expiratory) group of neurons.

FUNCTION

It inhibits the dorsal group and mainly responsible for expiration

(B) CHEMICAL CONTROL

Chemical control of rate of breathing is through chemoreceptors.

LOCATION OF CHEMORECEPTORS

AORTIC BODIES

CAROTID BODIES

AORTIC BODIES

The peripheral chemoreceptors which are located above and below the arch of aorta

are called Aortic bodies. It sends impulses to medulla through Vagus nerve.

CAROTID BODIES

Chemoreceptors which are located at the bifurcation of carotid arteries are called

Carotid bodies. It sends impulses to medulla through Glossopharyngeal nerve.

FUNCTION

Inc. in concentration of CO2 and H+ in blood are basic stimuli to increase the rate of

breathing which are monitered by these chemoreceptors and then send the impulses to

medulla oblongata which produce action potential in inspiratory muscles.

DISORDERS OF RESPIRATORY TRACT

(1) LUNG CANCER (BRONCHIAL CARCINOMA)

CAUSES

Smoking is a major risk factor either acitively or passively.

Asbestos, nickel, radioactive gases are associated with increased risk of bronchial

cascinoma

PHYSIOLOGICAL EFFECTS

+ LOSS OF CILIA

The toxic contents of smoke such as nicotine and SO2 cause the gradual loss of cilia

of epithelical cells so that dust and germ are settled inside the lungs.

+ ABNORMAL GROWTH OF MUCOUS GLANDS



Tumor arises by uncontrolled and abnormal growth of bronchial epithelium mucous

glands. The growth enlarges and some times obstruct a large bronchus.

The tumours cells can spread to other structures causing cancer.

SYMPTOMS

Cough- due to irritation

Breath lessness – due to obstruction.

(2)TUBERCLOSIS (KOCH’S DISEASE)(INFECTIOUS DISEASE OF LUNG)

CAUSE

Caused by a Bacterium called as “MYCOBECTERIUM TUBERCLOSIS”


Tuber Bacili causes

Invasion of infected region by macrophages

Fibrosis of lungs thus reducing the total amount of functional lung tissues

These effects cause

Increased work during breathing

Reduced vital and breathing capacity

Difficulty in diffusion of air from alveolar air into blood.

SYMPTOMS

Coughing (some time blood in sputum)

Chest pair

Shortness of breath

Fever

Sweating at night

Weight loss

Poor apetite

PREVENTION

A live vaccine (BCG) provides protection against tuberclosis.

3.COPD-(CHRONIC OBSTRUCTIVE PULMONARY DISEASE)

They include

A. Emphysema

B. Asthma

(3-A)EMPHYSEMA



CAUSES It is a chronic infection caused by inhaling Smoke and other toxic substances such as

Nitrogen dioxide and Sulphur dioxide


Long infection – Irritants deranges the normal protective mechanisms such as loss of

cilia, excess mucus secretion causing obstruction of air ways

Elasticity of lung is lost

Residual volume increases while vital capacity decreases.

Difficulty in expiration due to obstruction

Entrapment of air in alveoli

All these together cause the marked destruction of as much as 50-80% of alveolar

walls.

Loss of alveolar walls reduces the ability of lung to oxygenate the blood and remove

the CO2

Oxygen supply to body tissues especially brain decreases.

SYMPTOMS

Victim’s breathing becomes labored day by day.

Patient becomes depressed, irritable and sluggish.

Concentration of CO2 increases which may cause death.

(3-B) ASTHAMA

“Respiratory tract disorder in which there are recurrent attacks of breathlessness,

characteristically accompanied by wheezing when breathing out.”

CAUSES

It is usually caused by Allergic hypersensitivity to the plant pollens, dust, animal fur

or smoke or in older person may be due to common cough.

Heridity is major factor in development of Asthma.


Localized edema in walls of small bronchioles.

Secretion of thick mucus.

Spastic Contraction of bronchial smooth muscles (so the resistance in air flow

increases).

Residual volume of lung increases due to difficulty in expiration.

Thoracic cavity becomes permanently enlarged.

SYMPTOMS

The asthmatic patient usually can inspire quite adequately but has great difficulty in

expiring.



LUNG CAPACITIES

1. TOTAL AVERAGE LUNG CAPACITY

DEFINITION

“It is the maximum volume in which the lung can be expanded with greatest possible

inspiratory efforts.”

Or

“Total lung capacity is the combination of residual volume and vital capacity.

VALUE Total lung capacity = 5000 cm3 or 5 lit of air.

2. TIDAL VOLUME

“The amount of air which a person takes in and gives out during normal breathing is

called Tidal Volume.”

VALUE

450cm3 to 500 cm3 (1/2 litre)

3. INSPIRATORY RESERVE VOLUME

DEFINITION

‘“Amount of air inspired with a maximum inspiratory effort in excess of tidal

volume.”

VALUE 200 cm3 or 2 lit. (Average value)

4. EXPIRATORY RESERVE VOLUME

DEFINITION “Amount of air expelled by an active expiratory effort after passive expirations.”

VALUE

1000 cm3 or 1 litre.

5. VITAL CAPACITY

DEFINITION

“After an extra deep breath, the maximum volume of air inspired and expired is called

Vital capacity.”

Or



“It is the combination of inspiratory reserve volume, expiratory reserve volume and

tidal volume.”

VALUE

Averages about 4 litre.

6. RESIDUAL VOLUME

DEFINITION

“Amount of air which remains in lung after maximum expiratory effort is called

Residual volume.”

VALUE

Approximately 1 litre or 1000 cm3.

IMPORTANCE OF LUNG CAPACITY

Residual volume prevent the lung from collapsing completely.

Responsible for gaseous exchange in between breathing.

It is not stagnant since inspired air mixes with it each time.

Aging or Emphysema, etc can increase the residual volume at the expense of vital

capacity.

HAEMOGLOBIN

INTRODUCTION

“Haemoglobin is an iron containing respiratory pigment present in the red blood cells

of vertebrates and responsible for their red colour.”

STRUCTURE

Haemoglobin consists of

1. Heme

2. Protein (globin like chains)

1. HEME

One Haemoglobin molecule consists of 4 molecules of Heme. Each Heme molecule

contains an iron (Fe++) binding pocket. Thus one molecule of Haemoglobin can

combine with 4 iron atoms.

2. GLOBIN

Each Hb molecule contains four globin like chains (Two α chains and Two β chains).

ROLE OF HB DURING RESPIRATION

Two major functions are performed by Hb.

1. Transport of O2 from lung to tissues.

2. Transport of CO2 from tissues to lungs.



1. “TRANSPORT OF O2 FROM LUNGS TO TISSUES”

“Nearly 97% of O2 is transported from the lungs to the tissues in

combination with Hb.”

ATTACHMENT OF O2 WITH HB

It is the iron of Hb molecule which reversibly binds with oxygen. One Hb molecule

can bind 4 molecules of O2. Thus due to Hb, blood could carry 70 times more oxygen

than plasma.

MECHANISM OF TRANSPORT

Due to high O2 concentration in alveolar air, the O2 moves from air to the venous

blood where O2 concentration is low.

It combines loosely with Hb to form Oxyhemo Globin.

In this form, O2 is carried to the tissues where due to low oxygen concentration in

tissues, oxy Hb dissociates releasing oxygen, which enters in tissues.

Whole process can be represented by following equation.

2. “TRANSPORT OF CO2 FROM TISSUES TO LUNGS”

“Haemoglobin is also involved in 35% of transport of CO2 from tissues to alveolar

blood capillaries in alveoli.”

ATTACHMENT OF CO2 WITH HB

CO2 binds reversibly with NH2 group of Hb to form loose compound called

“Carboamino Haemoglobin.”

MECHANISM OF TRANSPORT

Carbon dioxide due to its higher concentration in tissue diffuses out into the blood

where it combines with Hb to form Carboamino Hb.

In the alveoli it breaks and CO2 diffuses out into the Alveoli from where it is expired.

MYOGLOBIN

INTRODUCTION “Myoglobin is a heme protein, smaller than Hb, found in muscles and giving red

colour to them.

STRUCTURE

Myoglobin consists of one heme molecule and one globin chain. It can combine with

one iron (Fe++) atom and can carry one molecule of O2.



FUNCTION OF MYOGLOBIN

Myoglobin has high affinity for O2 as compared to Haemoglobin so it binds more

tightly.

It stores the O2 within the muscles.

It supplies the O2 to the muscles when there is severe oxygen deficiency (During

exercise)

It can be represented as follows:

Mb + O2 ↔ MbO2

TRANSPORT OF GASES

Oxygen and carbondioxide are exchanged in, Alveoli by Diffusion.

O2 TRANSPORT

Blood returning into the lungs from all parts of body is depleted from oxygen. This

deoxygenated blood is dark maroon in colour to appear bluish through skin. It

becomes oxygenated in the lungs.

TWO FORMS OF O2 IN BLOOD

O2 is transported in the blood in two forms:

Dissolved form (3%)

Combination with Hb (97%) ® Oxyhaemoglobin

MECHANISM OF O2 TRANSPORT

+ DIFFUSION OF O2 FROM ALVEOLUS INTO PULMONARY BLOOD

The air inhaled into the lungs has high concentration of oxygen while venous blood in

pulmonary capillaries has low in concentration. Due to this difference in concentration

across the respiratory surface, oxygen diffuses into the blood flowing into capillaries

around the Alveoli. Now blood becomes oxygenated which is bright red in colour.

+ DIFFUSION OF O2 FROM CAPILLARIES INTO CELLS

Concentration of O2 in the arterial end of capillaries is much more greater

than concentration of O2 in the cells. So O2 diffuses from the blood to the body cells.

Since the blood takes in oxygen much more rapidly than water. Thus it can transport

enough oxygen to the tissues to meet their demand.

CO2 TRANSPORT

Blood returning from tissues contain excess of CO2 as a respiratory by-product,

which is eliminated from the body during expiration in the lungs.”

THREE FORMS OF CO2 IN BLOOD

Dissolved form (in plasma) – 5%



In form of HCO3- (in RBC’s) – 60%

In combination with Hb (Carboamino Hb) – 35%

+ DISSOLVED FORM

Only 5% of CO2 is transported in dissolved form in plasma. Here it combines with

H2O of plasma to form H2CO3. But this reaction is very slow as plasma does not

contain Carbonic Anhydrase to accelerate this reaction.

Reactions can be represented by following equations.

CO2 + H2O ↔ H2CO3

H2CO3 ↔HCO3- + H+

HCO3- + k+ ↔ KHCO3

+ IN FORM OF HCO3-

60% of CO2 is transported in the blood in form of HCO3- in RBC’s. Here it combines

with water to form H2CO3. But this reaction occurs rapidly in

RBC’s due to presence of Carbonic Anhydrase.

Reactions can be represented by following equations

CO2 + H2O ↔ H2CO3

H2CO3 ↔ HCO3- + H+

HCO3- + Na+ ↔ NaHCO3

+ IN COMBINATION WITH HB

As discussed previously in role of Hb.

MECHANISM OF CO2 TRANSPORT

+ DIFFUSION OF CO2 FROM CELLS INTO CAPILLARIES

CO2 is continuously synthesizing in the tissues as a result of metabolism. Thus due to

its higher concentration. CO2 diffuses from the tissues into blood, which becomes

deoxygenated.

+ DIFFUSION OF CO2 FROM PULMONARY BLOOD INTO ALVEOLUS Blood returning from tissues contain high concentration of CO2. This blood is

brought to lungs, where CO2 diffuses from the blood into alveolus where its

concentration is lower.

FACTORS EFFECTING THE TRANSPORT OF GASES

Following are some factors, which influence the transport of respiratory gases across

the alveolar wall.

1. Concentration Gradient

2. Presence of competitor such as CO

3. Moisture



4. Surfactant

5. pH

DIGESTION

“It is the process by which large complex insoluble organic food substances are

broken down into smaller simpler soluble molecules by the help of enzymes”.

Digestion in man is mechanical (break down) as well as chemical (enzymatic

hydrolysis)

NUTRITION

HETEROTROPHIC, i.e. man is dependent upon ready made food.

TYPE OF DIGESTION

EXTRACELLULAR, i.e. digestion takes place outside the cells but within GIT.

TYPE OF DIGESTIVE SYSTEM

TUBE LIKE DIGESTIVE SYSTEM, i.e,

Digestive cavity is separated from body cavity.

It has both openings, mouth and anus.

“Complete” digestive sytem

This one way tube is known as GASTRO-INTESTINAL TRACT (GIT)

ORGANS OF GASTRO-INTESTINAL SYSTEM

The adult digestive system is a tube approximately 4.5m (15ft) long and comprises of

(A) G I T

1. MOUTH

2. ORAL CAVITY -> TEETH, TONGUE

3. PHARYNX

4. OESOPHAGUS

5. STOMACH

6. SMALL INTESTINE -> DUODENUM, JEJUNUM, ILEUM

7. LARGE INTESTINE -> CAECUM, RECTUM, COLON

8. ANUS -> PAROTID

(B) ASSOCIATED GLANDS

1. SALIVARY GLANDS -> SUBLINGUAL, SUBMANDIBULAR

2. LIVER

3. PANCREAS

(1) MOUTH

The anterior or proximal opening of gut, which is bounded anteriorly by lips. It opens

into oral cavity.



FUNCTION

1. Lips close the mouth.

2. Lips also help in ingestion.

(2) ORAL CAVITY

It is a wide cavity supported by bones of skull

BOUNDARIES

Cheeks form side walls.

Tongue forms floor

Palate forms roof

Jaws form roof boundary of mouth.

+ JAWS

Upper jaw is fixed while lower jaw is moveable. Both jaws bear teeth.

CONTENT OF CAVITY

Teeth and Tongue

+ TEETH

“The hard calcified structures, meant for mastication (chewing)”

NUMBER OF SETS

Humans have 2 sets of teeth ® DIPHYODONT

(1) DECIDUOUS

The 20 teeth of first dentition, which are shed and replaced by permanent teeth.

(2) PERMEMANT

The 32 teeth of second dentition, which begin to appear in human at about 6 year of

age. It consisting of 8 incisors, 4 canines, 8 premolars and 12 molars.

+ Molars are absent in deciduous set.

HETERDONT They are embedded in gums -> THECODONT

STRUCTURE OF A TOOTH

Each tooth consist of 3 parts

1. CROWN

2. NECK

3. ROOT

FUNCTIONS

1. Incisors are cutting and biting teeth. Their flat sharp edges cut food into smaller

pieces.

2. Canines are pointed teeth and poorly developed in humans. They are used in

tearing, killing and piercing the prey.

3. Premolars and Molars are grinders and used for crushing the food.

4. Mastication increases surface are of food for action of enzymes.



5. If one attempt to swallow a food particle too large to enter ocsophagus, it may

block the trachea and may stop ventilation.

“DENTAL DISEASES”

PLAQUE

“A mixture of bacteria and salivary materials”

OR

“A soft thin film of food debris, mucin and dead epithelial cells deposited on teeth,

providing medium for growth of bacterias”

Plague plays an important role in development of dental caries, periodontal and

gingival disease. Calcified plaque forms dental calculus.

PERIODONTAL DISEASES

Accumulation of plaque causes inflammation of gums. Continuous inflammation may

spread to the root of tooth and destroy peridental layer. Eventually tooth becomes

loose and falls off or may have to be extracted.

DENTAL CALCULUS

Plaque combine with certain chemicals in saliva which become harden and calcified

forming deposits of calculus which cannot be removed by brushing.

DENTAL CARIES

When bacteria of plaque converts sugar of food into acid, the enamel (hardest

substance of body, covers dentin of crown of teeth) is dissolved slowly. When dentine

and pulp are attached, produce toothache and loss of teeth.

FACTOR CAUSING DENTAL CARIES

Prolonged exposure to sugary food stuff.

Disturbance of saliva composition

Lack of oral hygiene

Low levels of fluoride in drinking H2O

PREVENTION

Add ‘flouride’ in drinking H2O or milk

Take ‘flouride’ tablet

Use ‘flouride’ tooth paste.

TONGUE

Tongue is a muscular fleshy structure forming floor of oral cavity. Tongue has

a root

a tip and



a body

It is attached posteriorly and free anteriorly

TASTE BUDS

Taste buds respond to sweet, salt, acid and bitter taste, only when these substances are

dissolved in H2O of saliva.

Taste buds are most numerous on sides of vallate papillae. They are absent on mid

dorsal region of oral part of tongue.

TONGUE PAPILLAE

Papillae are projections of mucous membrane which gives characteristic roughness to

the tongue. These are of 3 types

VALLATE PAPILLAE

FUNGIFORM PAPILLAE

FILLIFORM PAPILLAE

FUNCTIONS

1. Its function is ‘Spoon-like’.

2. It mixes the masticated food with saliva

3. It helps in swalloing

4. It helps in sucking and testing food.

SALIVARY GLANDS

3 pairs of salivary glands.

(1) PAROTID

Lies at base of pinnae.

It is supplied by IX cranial nerve.

(2) SUB LINGUAL

Lies at base of tongue.

Supplied by VII cranial nerve.

(3) SUB MANDIBULAR

Lies at base of lower jaw.

Supplied by VII cranial nerve

FUNCTION

These three pairs produce about 1.5dm3 of saliva each day.

These glands are supplied by Parasympathetic Nervous System. Fibers of

parasympathic N.S lie in Cranial nerves. These nerves increase their secretion.

SALIVA

It is a watery secretion containing 95% H2O, some mucous, amylase and Lysozyme

enzyme.



Salivation is brought about by “Parasympathetic Nervous System.”

Saliva is secreted in response to the sight, thought, taste or smell of food.

FUNCTIONS

1. Mucous of Saliva moistens and lubricates the food particles prior to swallowing.

2. Salivary Amylase or Ptylin begins digestion of starch, first to dextrins and then to

maltose (dissacharide).

3. Lysozyme destroys the oral cavity pathogen bacteria. It has a cleansing action.

4. Water in Saliva, dissolve some of the molecules in food particle then they react

with chemo receptors in taste buds, giving sensation of taste, hence, the H2O enables

taste buds to respond.

5. Saliva is fully saturated with calcium and this prevents decalcification of teeth.

6. Saliva makes speech possible by moistening the mouth; it is not possible to talk if

the mouth is dry.

7. It acts as a lubricant and enables a bolus (a rounded mass of semi-solid, partially

digested food particles stick together by mucus) to be formed. The tongue pushes

bolus into pharynx.

3. PHARYNX

The musculo-membranous passage between mouth and posterior nares and the larynx

and oesophagus.

OPENINGS

It contains opening of oesophagus, glottis, Eustachian tube and internal nostrils.

PARTS OF PHARYNX

NASOPHARYNNX

The part above the level of soft palate is NASOPHARYNX, which communicates

with auditory tube.

OROPHARYNX

It lies between soft palate and upper edge of the epiglottis.

HYPOPHARYNX

It lies below the upper edge of epiglottis and opens into larynx and oesophagus.

FUNCTION -> SWALLOWING

Swallowing in its initial stages is voluntary but involuntary afterwards.

MECHANISM

1. As the bolus of food moves into the pharynx, the soft palate is elevated and lodges

against the back wall of pharynx sealing the nasal cavity and preventing food from

entering it.



2. The swallowing center inhibit respiration, raises the larynx and closes the glottis

(opening between vocal cords), keeping food from getting into trachea.

3. As the tongue forces the food further back into the pharynx, the bolus tilts the

epiglottis backward to cover the closed glottis.

4. This pharyngeal act of swallowing lasts about 1 second.

4. OESOPHAGUS

This is a narrow muscular tube of about 25cm long. It connects pharynx to stomach. It

passes through the thoracic cavity and penetrates the diaphragm, then it joins the

stomach a few cms below the diaphragm.

MUSCLES OF OESOPHAGUS

Upper-one third is surrounded by skeletal muscles.

Lower two-third is surrounded by smooth muscles.

SPHINCTERS (MUSCULAR VALVES)

1. Skeletal muscles, just below pharynx surrounding oesophagus form Upper

Oesophageal Sphincter.

2. Smooth muscles in last 4 cm of oesophagus forms Lower Oesophageal Sphincter. It

seals the exit of food.

FUNCTION

It conveys the food or fluid by Peristalsis.

PERISTALSIS

Alternate rhythmic contraction and relaxation waves in the muscle layers surrounding

a tube are called Peristaltic Waves.

It is the basic propulsive movement of GIT.

STIMULUS

Distention of oesophagus.

TIMING

An oesophageal peristaltic wave takes about ‘9 sec’ to reach stomach. Bolus is moved

toward stomach by progressive peristaltic wave which compresses the lumen and

forces the bolus ahead of it.

ANTI-PERISTALSIS

Peristalsis in opposite direction, i.e. from stomach towards pharynx.

STIMULUS

Early stages of GIT irritation.

Over distention.



VOMITING

Anti peristalsis begins to occur, some minute before vomiting appears. The initial

events of anti peristalsis may occur repeatedly without vomiting, called RETCHING.

1. Vomiting begins with a deep inspiration, closure of glottis and elevation of soft

palate.

2. Abdominal and thoracic muscles contract, raising intradominal pressure.

3. Stomach is squeezed, lower oesophageal sphincter relaxes allowing expulsion of

stomach content into oesophagus in form of VOMITUS.

5 OESOPHAGUS

Stomach is a hollow, muscular, distensible bag like organ.

LOCATION

Lying below the diaphragm on the left side of abdominal cavity.

STRUCTURE

It has 3 regions.

1 CARDIAC REGION

This is the anterior region which joins the oesophagus through a cardiac sphincter. It

has muscous glands which helps in lubrication of food.

2 BODY

The middle portion is body of stomach. The part to the left and above the entrance of

oesophagus is called FUNDUS of stomach. Body of stomach contain gastric glands.

Gastric glands contain 3 types of cells.

MUCOUS CELLS

These cells are present at opening of gastric glands and secrete mucous.

It lubricates the food and passage.

It also protects the epithelium from self digestion by pepsin.

OXYNTIC / PARIETAL CELLS

They lie deeper within the glands and secrete dilute HCl having a pH of 1.5 – 2.5.

Kills microbes

Solublization of food particles.

Activate the inactive enzyme pepsinogen into Pepsin.

CHIEF CELL / ZYMOGEN CELLS

Deeper in the glands and secrete enzyme precursor Pepsinogen.



After converting into Pepsin, it acts upon proteins and convert them into short chain

polypeptides, Peptones.

The collective secretion of the above mentioned 3 cells is called as GASTRIC JUICE

PYLORIC REGION

The posterior region is the terminal narrow pyloric region or Antrum. It opens into

duodenum through pyloric sphincter / pylorus.

ITS SECRETION -> GASTRIN

This region does not secrete acid. It secretes mucous, pepsinogen and a hormone

GASTRIN. Endocrine cells which secrete GASTRIN are scattered throughout

epithelium of antrum.

STIMULUS

Partially digested proteins.

ACTION

Activate gastric glands to produce gastric juices.

“RENIN”-ADDITIONAL ENZYME IN INFANT

In infants, RENIN is secreted which curdles the milk.

FUNCTION OF STOMACH

(1) STORAGE OF FOOD

Pylorus acts as a valve and retain food in the stomach for about 4 hours. Periodic

relaxation of pylorus releases small quantities of chyme into duodenum.

(2) MECHANICAL DIGESTION

The weak peristaltic waves also called mixing waves move along the stomach wall

once every 20 seconds. These waves not only mix the food with secretions but also

move mixed contents forward.

(3) CHEMICAL DIGESTION

Gastric juice converts food to a creamy paste called CHYME.

6. SMALL INTESTINE

The small intestine is a coiled tube approximately 6 meters long and 2.5 cm wide,

leading from stomach to large intestine. It fills most of the abdominal cavity.

DIVISIONS

There are 3 divisions.



A. DUODENUM

It begins after pyloric stomach and ends at jejunum. Its length is about 30cm.

SECRETION

Pancreatic juice from pancreas by pancreatic duet and bile from gall bladder by

common bile duct act on chyme from stomach. Both ducts open via a common

opening in duodenum.

BILE

SYNTHESIS, STORAGE AND SECRETION

Bile is made in liver and enters the duodenum via the bile duct. It stores in gall

bladder.

COLOUR

Bile is yellow in colour but changes to green due to exposure to air.

CONSTITUENT

Water.

Bile Salts

+ BILE SALTS

These are sodium salts of compounds of cholestrol. NaHCO3 is also present which

neutralizes the acidity of gastric juice and make the chyme alkaline.

The main bile salts are for emulsification of fats.

EMULSIFICATION Break down of large fat particles into small droplets so that they

can mix well with H2O to form emulsions.

+ BILE PIGMENTS

BILIRUBIN and BILIVERDIN are excretory products formed by breakdown of

haemaglobin of worn out RBCs in the liver.

ACTION OF ‘CHOLECYSTOKININ (CCK)’

CCK is a hormone and produced by cells of small intestine.

STIMULI FOR HORMONE RELEASE

Fatty food in duodenum.

ACTION

CCK is released in blood and reaches to gall bladder and causes it to contract. Due to

contraction of gall bladder, bile enters the duodenum.

‘PANCREATIC JUICE’

Pancreatic juice is produced in pancreas by its exocrine function and secreted via

pancreatic duct. It is a colourless fluid.



ACTION OF SECRETIN

Secretion is also a hormone and produced by cells of small intestine.

STIMULI

Acid (HCl) carried with chyme in small intestine.

ACTION

It increases the secretion of pancreatic juice and also increases bicarbonate secretion

in bile.

CONSTITUENTS

(1) TRYPSIN (PROTEASE)

It is secreted in an inactive form called Trypsinogen which is activated by action of an

enzyme produced by duodenum called enterokinase.

ACTION

Break proteins and long chain polypeptides into small peptide fragments.

(2) CHYMOTRYPSIN (PROTEASE)

It is also secreted in inactive form, Chymotrypsinogen which is converted into

chymotrypsin by action of Trypsin.

ACTION

Converts casein (milk proteins) into short chain peptide.

(3) AMYLASE

It is similar to salivary amylase. It acts on polysaccharides (Glycogen and Starch) and

convert them into maltose (a disaccharide).

(4) LIPASE

It acts on emulsified fat droplets. It splits off lipid into fatty acid and glycerol, hance

the digestion of fat is completed in duodenum.

(B) JEJUNUM

It extends from duodenum to illeum. It is 2.4 meters long. Here the digestion of food

is completed.

COLLECTION OF PEPTIDASES, EREPSIN

Peptidases complete the breakdown of polypeptide into amino acids.

NUCLEOTIDASE

It converts nucleotides into nucleoside. End products of digestion, i.e, monosaccharide

and A.As are liberated in lumen of small intestine for absorption in ileum.



(C) ILEUM

It is the last and longest part of small intestine. Its length is about 3.6 meters long. It

contains digested food in true solution form.

STRUCTURE

The inner wall (Mucosa and Submucosa) of small intestine is thrown into various

folds. These folds have finger-like microscopic projections called villi.

VILLI

Each villus is lined with epithelial cells having microvilli on their free

surfaces.

Their walls are richly supplied with blood vessels and lymph vessels called Lacteals.

Some smooth muscles are also present in villi.

MECHANISM OF ABSORPTION

Major function of ileum is absorption of digested food, which is facilitated by highly

folded inner wall of intestine with villi on their surfaces.

This increases the absorptive area. Villi are able to move back and forth due to muscle

fibers in them.

The monosaccharide and A.As are absorbed into blood capillaries by Diffusion or

Active Transport.

Fatty acid and glycerol enter epithelial cells of villi, covert into triglycerols and enters

Lacteals and pass into blood stream.

BLOOD DRAINAGE OF INTESTINE

All capillaries converge to form hepatic portal vein, which delivers absorbed nutrients

to liver.

7. LARGE INTESTINE

Small intestine opens into large intestine, which is a large diameter tube about 6.5 cm.

It is not coiled by relatively has 3 straight segments.

+ Caecum

+ Colon

+ Rectum

+ CAECUM

Caecum is a blind ended pouch placed in the lower right side of abdominal cavity. It

gives a 10cm long finger like projection, Appendix. Appendix is a vestigial organ, i.e.

an organ present in rudimentary form and has no function but has well developed

function in ancestors.



FUNCTION

Symbiotic bacteria, present in caecum, help in digestion of cellulose, which is not

digested by man, as enzyme for digestion is absent.

+ COLON

Colon is longest part and has 3 regions :

+ Ascending colon

+ Transverse Colon

+ Descending Colon

-> SIGMOID COLON is terminal part of Descending Colon.

FUNCTION

Inorganic salts, water and mineral absorbed in colon. Some metabolic waste products

and excess calcium of body as salts are excreted into large intestine. Each day 500 ml

of intestinal content enter the colon and during its passage the amount reduced to 150

ml due to absorption of H2O.

+ RECTUM

Rectum is last portion, it stores faeces for some time.

When the faeces enter into rectum, it brings about a desire for defecation. The process

by which faeces passes out is called Egestion.

SYMBIOTIC BACTERIA

Many symbiotic bacteria in large intestine provide the body with a source of vitamin

and A.As, especially vitamin B complex and K, which are absorbed in blood stream.

Administration of Broad-spectrum antibiotics destroys these bacteria and a vitamin

deficiency results, which is then make up by vitamin intakes.

8. ANUS

External opening of digestive system is ANUS.

SPHINCTERS

Two sphincters surround the anus:

+ Internal Sphinter -> made up of smooth muscle and under Autonomic control

(involuntary control).

+ Outer Sphincter -> made up of skeletal muscle and under Somatic Control

(voluntary control).

FAECUS

Faecus consists of:

Dead bacteria, cellulose, Plant fibers, dead mucosal cells, mucous, cholesterol, bile

pigment derivatives and H2O.

(DIAGRAM “DIGESTIVE SYSTEM” FROM BOOK XI)



9. LIVER

Liver is the largest organ and gland of body. It weighs about 1.5 kg . It is also called

‘HEPAR’.

COLOUR

It is reddish brown in colour.

LOCATION

It lies below the diaphragm on right side.

LOBES OF LIVER

Liver has 2 lobes, i.e. Right and Left. Left is further divided into two lobes.

FUNCTIONS OF LIVER

‘AS A METABOLIC FACTORY’

It maintains the appropriate level of nutrients in blood and body. It is performed in 3

ways.

A. GLUCOSE METABOLISM

1. Additional (Surplus) Glucose is converted into Glycogen by action of INSULIN

after every meal. This is called Glycogenesis.

2. Glycogen is splitted into Glucose for body needs. This is called Glycogenolysis.

3. New glucose for body requirement is formed by non-carbohydrate compounds.

This is called Gluconeogenesis.

B. A.AS METABOLISM

A.As are also stored after deamination (removal of NH2 group), which forms Urea.

C. FATTY ACID METABOLISM

It also processes F.As and stores the products as Ketone Bodies, which are released as

nutrients for active muscles.

‘AS A DETOXIFICATION CENTER’

Poisons and toxic substances, which can harm the body, are degraded into harmless

compounds. It excrete out bile pigments and waste products.

‘AS A STORAGE ORGAN’

It stores vitamins and also produces proteins and coagulating factors of blood.

GALL BLADER

It lies on undersurface of liver, a pear shaped organ.



FUNCTION

It concentrates and stores the bile secreted by liver.

BILIARY TRACFT

Two hepatic ducts from liver bring bile and join the cystic duct from gall bladder.

This form common bile duct, which joins Pancreatic duct coming from pancreas

bringing pancreatic juice. These 2 ducts open into duodenum at same opening.

10.PANCREAS

A large elongated gland situated transversely behind the stomach, between spleen and

duodenum.

PARTS OF PANCREAS

HEAD

It is the right extremity and directed downwards.

TAIL

Left extremity is transverse and terminates close to spleen.

BODY

The main portion in middle.

DUCT

Pancreatic duct opens into duodenum with common bile duct and delivers pancreatic

juices.

WORKING AS A GLAND

It works both as an endocrine and exocrine gland.

ENDOCRINE PANCREAS

Endocrine part consists of ISLETS OF LANGERHANS.

The islets contain.

α cell (ALPHA)

Produce GLUCAGON which increases blood glucose level.

β cell (BETA)

Produce INSULIN which reduces blood glucose level.

Δ cell (DELTA)

Produce Somatostatin (SS) which inhibit the release of many harmones.

P P cells

Secrete pancreatic polypeptide.



EXOCRINE PANCREASE

The exocrine part consists of pancreatic acini. Acini are secretory unit that produce

and secrete pancreatic juice into duodenum which contain enzymes essential to

digestion.

DISORDERS OF ‘GIT’

(1) DIARRHOEA

Abnormal frequency and liquidity of fecal discharges. It is the rapid movement of

fecal matter through large intestine.

CAUSES

ENTRITIS

It may be caused by infection of intestinal wall (mucosa) by a virus or bacteria. Due to

infection, mucosa becomes irritated and motility of intestinal wall increases.

CHOLERA

Cholera is a bacterial disease caused by VIBRIO CHOLERA. It can cause diarrhoea.

It causes extreme amount of HCO3- (bicarbonates ion) and Na and H2O to be

secreted in faeces. It may causes death.

PSYCOGENIC DIARRHOEA

It is caused by nervous tension. In the young and elderly, diarrhoea may lead to a

serious depletion of H2O and inorganic salts.

(2) DYSENTARY

Acute inflammation of intestines especially of the colon.

SYMPTOMS

Pain in abdomen, tenesmus (straining), frequent stool containing blood and mucus.

CAUSES

PROTOZOA. (like amoebic dysentery)

PARASITIC WORMS.

BACTERIA. (like bacillary dysentery)

CHEMICAL IRRITANTS.

(3) CONSTIPATION



Infrequent or difficult evacuation of faeces. OR Slow movement of faeces through

large intestine.

Faeces becomes hard due to long time available for H2O absorption.

CAUSE

Irregular bowel habits that have developed through a life time of inhibition of normal

defection reflaxes.

TREATMENT

Laxatives are used

Substance which hold H2O with them

(4) PILES

Also called HAEMORRHOIDS Varicose dialatation of veins occurring in relation to

anus, resulting from a persistence increase in pressure.

EXTERNAL PILES

Venous dialatation covered with modified anal skin.

INTERNAL PILES

Dilatation of veins covered by mucous membrane.

CAUSE

CONSTIPATION

The pressure exerted to defecate stretches skin with vein and causes dilation.

PREVENTION

Can be avoided by regular habit of defecation and by use of fiber diet.

(5) DYSPEPSIA

Impairment of the power or function of digestion, usually applied to epigastria

discomfort following meals.

CAUSE

May be due to peptic ulcer.

SYMPTOMS

Heart burn.

Flatulence (distended with gas)

Anorexia, nausea, vomiting with or without abdominal pair.



FUNCTIONAL / NON-ULCER DYSPEPSIA

Dyspepsia in which symptoms resemble those of peptic ulcer, although no ulcer is

detectable. It is caused by disturbance in moter function of alimentary tract.

(6) PEPTIC ULCER

Since pepsin, is a protein digesting enzyme, it may digest the stomach wall, the first

part of duodenum or rarely lower part of oesophagus where stomach juices frequently

refluxes. This condition is called Peptic Ulcers.

GASTRIC ULCERS

DUODENAL ULCERS

CAUSES

Excessive secretion of acid and pepsin.

It may be hereditary.

Psychogenic factors.

COMPLICATIONS

Complications of peptic ulcers are perforation, haemorrhage and obstruction.

INVESTIGATIONS

1. Acid output of stomach is studied.

2. Ulcers cavity may be shown up on X-rays after ingestion of insoluble barium

sulphate (Barium meal).

3. It may be seen using optical instrument passed down through oesophagus

(endoscopy)

(7) FOOD POISONING

Also called GASTRO-ENTRITIS

CAUSES

INFECTION

By bacteria, virus, protozoa. ‘Salmonella’ species are very common.

NON-INFECTIOUS

Allergy, irritating food or drink.

SYMPTOMS

Vomiting and diarrhoea within 48 hours.

(8) MAL NUTRITION

Any disorder of nutrition due to unbalanced diet or due to defective assimilation or

utilization of foods.



An organism may be deficient or may receives excess of one or more nutrients for a

long period of time.

UNDER NUTRITION

Deficiency is known as under-nutrition. It is most common problem of under

developed countries.

OVER NUTRITION

Excess is known as over-nutrition. Obesity with heart problems and reduced life

expactency are its symptoms and are more common in developed countries.

(9) OBESITY AND OVER WEIGHT

Increase in body weight beyond the limitation of skeletal and physical need as the

result of accumulation (excessive) of fat in the body.

It is the most common nutritional disorder. It is most prevalent in middle age. It may

be hereditary or family tendency over weight results in rate of mortality.

(10) ANOREXIA NERVOSA

Loss or lack of appetite for food is called Anorexia.

ANOREXIA NERVOSA

An eating disorder affecting young females, characterized by refusal to maintain a

normal minimal body weight, intence fear of gaining body weight, intense fear of

gaining weight or becoming obese. Sometimes accompanied by spontaneous or

induced vomiting.

(11) BULIMIA NERVOSA

Exclusively found in women and the age of onset is slightly older than for anorexia.

Recurrent episodes (bouts) of binge (uncontrolled) eating. Lack of self control over

eating during binges.

Attacks occur twice a week and involve rich foods such as cakes and chocolates and

dairy products.

IMMUNITY

DEFINITION “The ability of human body to resist almost all types of micro-organisms, their toxins

if any, foreign cells & abnormal cells of the body is termed as “Immunity”

IMMUNOLOGY



DEFINITION “The study of functioning & disorders of Immune system is termed as “Immunology”.

IMMUNE SYSTEM

Immunity is conferred to animals through the activities of the Immune System, which

combats infectious agents.

DEFINITION “Immune System is a collection of cells & proteins that work to protect the body from

potentially harmful, infectious micro-organisms”

MAIN FUNCTIONS OF IMMUNE SYSTEM

Protection of body from all types of micro organisms & toxins that tend to damage the

tissues and organs of body.

ADDITIONAL FUNCTIONS

Immune system also play important role in:

Control of cancer

Allergy

Hypersensitivity

Rejection problems when organs or tissues are transplanted.

DIVISIONS OF IMMUNE SYSTEM

Immune system can be divided into two functional divisions:

1. Innate Immunity System

2. Acquired Immunity System

INNATE IMMUNITY

DEFINITION “The NON SPECIFIC type of immunity which result from general processes , rather

than from processes directed at specific disease organism (Such as antigen –antibody

reaction) is called. INNATE OR NATURAL IMMUNITY & the system which is

responsible for this type of immunity is called Innate IMMUNITY System.

TYPES OF BARRIERS PROVIDED BY INNATE IMMUNITY SYSTEM

This system provides two types of barriers:

Physical Barrier

Chemical Barrier

PHYSICAL BARRIERS

SKIN



MUCOUS MEMBRANE & etc.

CHEMICAL BARRIERS

Lysozyme

Gastric juice (Acidic secretion of stomach) & etc.

FIRST LINE OF DEFENCE

Skin, Mucous membrane & their secretions act as “First line of Defence”

1. SKIN

The intact skin provides an impenetrable barrier to the vast majority of infectious

agents.

2. MUCOUS MEMBRANES Most of the micro-organisms can enter only through the mucous membranes that lines

the digestive, respiratory & urogenital tracts. However these areas are protected by

movements of mucous & secretions (e.g Lysozyme in tears) to destroy many microbs.

3. ACIDIC SECRETIONS Most of he microorganisms present in food or trapped in swallowed mucus from the

upper respiratory tracts are destroyed by highly acidic gastric juice of stomach.

SECOND LINE OF DEFENSE

If some how micro-organisms are able to penetrate the outer layer of the skin or

mucous membrance, they encounter a second line of Defence offered by Innate

Immunity system.

It is non specific & comprises of

1. PHAGOCYTES

2. ANTIMICROBIAL PROTEINS

3. INFLAMMATORY RESPONSE

1. PHAGOCYTES

Phagocytes are certain type of WBC’S which can injest internalize & destroy the

particles including infectious agents.

EXAMPLES OF PHAGOCYTIC CELLS

NEUTROPHILS

MACROPHAGES

NEUTROPHILS

Neutrophils (Polymorphonuclear Neutrophiles are short lived phagocytic cells which

can ingest the bacteria or any foreign matter very actively.



MACROPHAGES (BIG EATERS)

The other phagocytic cells, the MONOCYTE can develop into large LONG-LIVED

MACRO PHAGES when they reside in various tissues of body. ALSO CALLED AS

ANTIGEN PRESENTING CELLS.

Macrophages not only destroy individual micro organisms but also play a crucial rule

in further immune response by “Presenting” parts of that microorganisms to other

cells of immune system. For this reason, they are termed as “ANTIGEN

PRESENTING CELLS.

NATURAL KILLER (NK ) CELLS

Natural killer cells (NK Cells ) are the large lymphocytes, which destroy the

Virally infected own cells of the body

Foreign cells

Abnormal cells (cancerous cells)

MECHANISM OF ACTION (CYTOTOXICITY)

NK cells do not phagocytize the target cells, instead, they bind to their target cells,

release some PORE FORMING PROTEINS (PERFORINS), that literally punch large

round holes in the membrane of attacked cells & eventually cause lysis of the target

cells. This kind of destroying the target cells is called “CYTOTOXICITY”

2. ANTIMICROBIAL PROTEINS

EXAMPLES

Important antimicrobial proteins are:

Lysozyme

Compliment proteins

Interferon

LYSOZYMES

Lysozyme, is a mucolytic polysaccharide that causes the LYSIS OF BACTERIA it is

present in TEARS, SALIVA, & MUCUS SECRETION.

COMPLEMENT PROTEINS

Complement is a collective terms that describes a system of about 20 PROTEINS,

many of which are INACTIVE ENZYME PRECURSORS. The principal actors in

this system are 11 Proteins. All these proteins are present among the Plasma Proteins.

ACTIVATION OF COMPLIMENT PROTEINS

These proteins can be activated by two ways.

CLASSICAL PATH WAY-Act in Adaptive Immunity system.

ALTERNATIVE PATH WAY- Act in Innate Immunity System.



FUNCTIONS

Main functions of compliment proteins are as follows:

1. DIRECT LYSIS OF BACTERIA

2. PROMOTE THE PHAGOCYTOSIS OF BACTERIA

3. NEUTRILIZATION OF VIRUSES

4. CHEMOATTRACTANTS FOR MACROPHAGES.

INTERFERONS (ANTIVIRAL AGENTS)

Interferon are secreted by virally infected cells or some lymphocytes to induce a state

of ANTI VIRAL RESISTANCE in unaffected tissues of the body.

3. INFLAMMATION

Inflammation is the body’s reaction to an injury or by entry of micro organisms.

EFFECTS OF INFLAMMATION

A cascade of chemical reactions take place during inflammatory response.

1. When injured, BASOPHILS and MAST CELLS release a substance called

HISTAMINE which causes.

Increased permeability of adjacent capillaries.

Local vasodilatation

Increased leakage of capillaries.

2. Due to CHEMOTAXIS, Phagocytes & macrophages are attracted at the injured

site. Thus Phagocytes literally eat up microorganisms, dirt, cell debris & etc forming

pus.

SYMPTOMS

Redness, heat, swelling, pain in injured tissue.

FEVER -(ALSO CONTRIBUTES TO DEFENSE OF BODY)

In case of warm blooded animals, a no. of micro organisms who escape away from

inflammatory response to infect some large part of the body, trigger FEVER. It is

usually caused by WBC’S, that release the substance called as PYROGEN.

FUNCTIONS

High fever is dangerous but moderate fever contributes to the defense of the body.

It inhibits the growth of micro-organisms.

May speed up the repair of damaged tissues.

Facilitates the phagocytosis, increase the production of interferons.

ADAPTIVE IMMUNE SYSTEM



DEFINITION “The specific type of Immunity which does not develop until after the body is first

attacked by a bacterial disease or a toxin, is called “Adaptive or Acquired Immunity”.

The system which provides this type of immunity is called “ADAPTIVE or

ACQUIRED IMMUNE SYSTEM”

OR

“Acquired Immunity is provided by special Immune System that form Antibodies &

activated lymphocytes that attack & destroy the specific organisms or toxins. This is

the THIRD LINE OF DEFENCE.

DEVELOPMENT OF IMMUNE SYSTEM (LYMPHOCYTES ARE THE

BASIS OF ADAPTIVE IMMUNE SYSTEM)

Acquired Immune system is actually the product of body’s Lymphocytic system. The

responses of adaptive Immune system is provided by Lymphocytes.

TYPES OF LYMPHOCYTES

During fetal development, all lymphocytes come from Bone Marrow. But depending

upon their migration & maturity, they can be divided into two populations.

1. “T” – Cells or “T” LYMPHOCYTES

2. “B” – Cells or “B” LYMPHOCYTES.

1. “T” LYMPHOCYTES

DEFINITION

“The lymphocytes that are destined to eventually form ACTIVATED “T”

LYMPOCYTES first migrate to & then mature in THYMUS GLAND, that is why,

they are called as “T” LYMPHOCYTES”

FUNCTIONS

These are responsible for “CELL-MEDIATED IMMUNITY

2. “B” LYMPHOCYTES

DEFINITION

“The lymphocytes that are destined to form ANTIBODIES are processed first in the

LIVER (before birth) & then in BONE MARROW (after the birth). This population of

cells was first discovered in birds where processing occurs in BURSA OF

FABRICIUS (not found in mammals), hence they are called as “B”

LYMPHOCYTES.”

FUNCTIONS

These are responsible for HUMORAL IMMUNITY



ADAPTIVE IMMUNE SYSTEM IS INITIATED BY ANTIGENS

In order to develop a specific immune response, the immune system must recognize

the invading organisms and / or foreign proteins from its self tissues & proteins.

ANTIGEN

Any foreign substance, that elicit the immune response is called antigen. In general

Antigens are proteins or large polysaccharides.

RESPONSE OF IMMUNE SYSTEM TO ANTIGEN

The immune system responds to an antigen by ACTIVATING LYMPHOCYTES &

PRODUCING ANTIBODIES (Soluble Proteins). The antibody combines with

antigen & helps to eliminate it from the body.

BASIC TYPES OF ADAPTIVE IMMUNITY

The adaptive immune system mounts two types of attacks on invading micro-

organisms.

1. HUMORAL IMMUNITY

2. CELL MEDIATED IMMUNITY (CMI)

1. HUMORAL IMMUNITY

DEFINITION

“The immunity which is mediated by circulating antibodies produced by B-

lymphocytes is called “ HUMORAL IMMUNITY”.

MAJOR FUCTIONS OF HUMORAL IMMUNITY

Humoral Immunity provides major defence against “BACTERIAL INFECTIONS

MECHANISM OF ACTION OF B CELLS

“B” CELL RECEPTORS

Each B-cell has specific type of antibodies on its cell surface. This antibody serves as

ANTIGENIC RECEPTOR.

ACTIVATION OF SPECIFIC “B” CELLS

On entry of foreign antigen, those B cells specific for that antigen enlarge

immediately, becomes activated & form two types of cells:

1. PLASMA CELLS

2. MEMORY CELLS

1. PLASMA CELLS The activated B-cells proliferate rapidly & transform into enlarged effectors cells

called plasma cells.



FUNCTION Plasma cells secrete ANTIBODIES into the circulation that help to eliminate that

particular antigen.

ACTIONS OF ANTIBODIES.

After the formation of antigen-antibody complex antibody can inactivate the invading

agent in one of the several ways.

By activation of complement system that cause the Lysis.

Direct Phagocytosis.

Neutralization of the toxins released by bacteria.

Agglutination of microorganism.

2. MEMORY CELLS

DEFINITION Some of the activated B-cells don’t go on to form the plasma cells but instead, form

moderate number of new B-cells, which don’t secrete antibodies such cells are called

as Memory cells.

FUNCTIONS The memory cells play important role in future immunity to this specific organism in

case of re-infection.

2. CELL MEDIATED IMMUNITY (CMI)

DEFINITION The second type of acquired immunity is achieved through the formation of large

number of Activated LYMPHOCYTES. This is called cell mediated or T-cell

immunity.

FUNCTIONS OF CMI

CMI is responsible for delayed allergic reactions & rejection of transplantation of

foreign tissue.

It provides major defence against infections due to VIRUSES, FUNGI, TUBERCLE

BACILLI & some parasites.

It also provides defence against TUMOUR CELLS.

MECHANISM OF ACTION OF “T”-CELLS. T-CELL RECEPTORS (TCRS)

Antigens bind with specific RECEPTOR MOLECULES on the surface of T-Cells, in

the same way that they bind the antibodies.



ACTIVATION OF SPECIFIC “T” CELLS.

On exposure to proper antigen, the “T” cells of specific type proliferate & release

large no. of activated T-Cells.

SEVERAL TYPES OF “T” CELLS

Different types of T cells are classified into four major groups.

1. HELPER “T” CELLS

2. CYTOTOXIC “T” CELLS

3. SUPRESSER “T” CELLS

4. MEMORY “T” CELLS

1. HELPER “T” CELLS

Helper T cells are the MAJOR REGULATOR of all the immune functions.

RECEPTORS

Helper T cell receptors actually recognize a combination of antigen fragment & one of

the body’s own self marker called. “MAJOR HISTO-COMPATIBILITY” (MHC)

CLASS II molecules on the surface of macrophages or B cells.

FUNCTIONS

Helper T-cells secrete the LYMPHOKINES which stimulate the production of both

CYTOTOXIC & SUPRESSER TOXINS.

2. CYTOTOXIC “T” CELLS (KILLER CELLS)

RECEPTORS

Receptors on the surface of cytotoxic ‘T” cells recognize a combination of antigen

fragment & self surface marker molecules called MHC CLASS I , found on every

nucleated cells of its own body.

FUNCTIONS They are especially lethal to virally infected cells. They also destroy the cancer cells,

heart transplant cells & other foreign cells.

3. SUPRESSOR “T” CELLS

Along with helper cells, In supressor, T-cells are classified as Regulatory T-Cells

FUNCTIONS

After the conquerence of infection, they seems to shut off the immune response in

both B-cells & cytotoxic T-cells.

4. MEMORY “T” CELLS During CMI response, some T-cells turn into MEMORY CELLS



FUNCTION Memory cells protect the body in case of reaction in future.

TYPES OF IMMUNE RESPONSE

The immune system has also the ability to memorize the antigen it has encountered.

Thus upon subsequent exposure to the same pathogen responds in two different ways.

1. Primary Immune Response

2. Secondary Immune Response

1. PRIMARY IMMUNE RESPONSE

DEFINITION The first exposure to an antigen to the immune system elicits formation of clones of

effectors cells to develop specific immunity with in 5 to 10 days. This response of

immune system is termed as Primary Immune response.

CHARACTERISTICS

DELAYED APPEARANCE

WEAK POTENCY

SHORT LIFE

2. SECONDARY IMMUNE RESPONSE

DEFINITION Subsequent exposure of same antigen causes a much more rapid & much more potent

antibody response. This is called Secondary Immune response. It develops to it max.

with in 3-5 days.

CHARACTERISTICS

Rapid & quicker appearance

Far more potent

Longer duration (form antibodies for many months rather than for only a few weeks.)

BASIS OF SECONDARY RESPONSE (IMMUNOLOGICAL MEMORY)

The quicker secondary response is made possible due to ability called

“Immunological Memory” of the immune system. It is based upon the long lasting

memory cells produced with short lived effectors cells of pri immune response. The

development of memory cells may provide life long protection against some diseases

like chicken pox.

ACTIVE & PASSIVE IMMUNITY

ACTIVE IMMUNITY



DEFINITION The immunity which is acquired by own immune response is called active immunity

FUNCTION OF ACTIVE IMMUNITY

Active immunity due to development of immunological memory provide LONG

TERM PROTECTION, even in some diseases (e.g in chicken Pox ) life long

protection is provided.

TYPES OF ACTIVE IMMUNITY

There are two types.

1. Natural active immunity

2. Artificial active Immunity

1. NATURAL ACTIVE IMMUNITY

DEFINITION

When the active immunity is acquired as a consequence of natural infection then it is

called Natural active immunity”

2. ARTIFICIAL ACTIVE IMMUNITY

DEFINITION

Active immunity can be acquired artificially by vaccination. In this case it is said to be

“ARTIFICIAL ACTIVE IMMUNITY”

PASSIVE IMMUNITY

DEFINITION Temporary immunity which is achieved in a person without injecting an antigen, by

transferring the antibodies, activated T-cells or both obtain from another person or

even an animal, is called passive immunity.

FUNCTIONS OF PASSIVE IMMUNITY

Although, acquired passive immunity is short lived (last for 2-3 weeks), it boosts the

immune response of the victim several folds.

TYPES OF PASSIVE IMMUNITY

There are 2 Types:

1. Natural passive Immunity

2. Artificial passive Immunity



1. NATURAL PASSIVE IMMUNITY

DEFINITION

When antibodies are transferred from one person to another of the same species

during natural processes, then such immunity is called Natural passive immunity.

EXAMPLE A pregnant woman passes some of the antibodies to her fetus through placenta. The

first breast feeding, the colostrum, of mother pass certain antibodies to her newly born

infant.

2. ARTIFICIAL PASSIVE IMMUNITY

DEFINITION

PASSIVE IMMUNITY can also be transferred artificially by introducing antibodies

derived from animals or human being who are already actively immunized to that

disease. This is called artificial passive immunity.

EXAMPLE

RABIES is treated in man by injecting antibodies derided from persons who have

been already vaccinated against rabies. This confers the rapid immunity to combat the

rapidly progressing rabies in new victim.

IMMUNIZATION

The process of inducing immunity as a preventive measure against certain infectious

diseases is called immunization.

ADVANTAGES OF IMMUNIZATION

The incidence of number of diseases (e.g Diptheria, Measles) has declined

dramatically since the introduction of effective immunization programmes. Some

dread full diseases (e.g. Tuberclosis) is now under control.

1- CAESAL PINIOIDEAE/CASIA FAMILY

CLASSIFICATION

DIVISION : ANGIOSPERMS

CLASS : DICOTYLEDON

SUBCLASS : POLYPETALAE

SERIES : CALCIFLORAE

ORDER : ROSALES

FAMILY : LEGUMINOSAE



SUB-FAMILY : CAESALPINIOIDEAE OR CAESALPINIACEAE.

GENERAL CHARACTERS

Majority of these plants are trees or shrubs, about 135 genera and 5800 species are

known .

VEGETATIVE CHARACTERS

ROOT Usually, Taproot with nodules and primary, secondary and tertiary divisions.

STEM Usually, Climbing stem or erect herbaceous or woody, Some plants show xerophytic

character.

LEAVES

Usually, Compound leaves bipinnate, stipulate.

INFLORESCENCE

Usually, Racemose.

FLORAL CHARACTER

Usually, Complete, bisexual, perigynous, zygomorphic, pentamerous.

CALYX 5 sepals, polysepalous, imbricate or valvate, Green in colour.

COROLLA 5 petals, poly petalous, imbricate aestivation.

ANDROECIUM Usually, 10 stamens, polyanderous, exerted, extrose.

GYNOECIUM Usually Monocarpillary, perigynous, placentational marginal, unilocular with many

ovules.

FLORAL FORMULA

+ , Q , K(5) , C(5) , A10 , G1/



POLLINATION Usually, Cross pollination by insects (entomophilly)

SEEDS Usually, Both endospermic and non-endospermic.

FRUIT

Legume pod.

ECONOMICAL IMPORTANCE

MEDICINAL PLANS

Amaltas

Kachnar

Tamarindus Indica

Panwar. e.t.c.

ORNAMENTALS

Parkinsonia

Gul-e-mohar

Cacia sophera

DYES AND STAINING Haemotoxylin is obtained from haemotoxylon campechianom.

EDIBLE FRUIT Lomentum (Imli)

FIBER

Suitable fiber for paper making is obtained from parkinsonia Aculeata.

FAMILIAR PLANTS

Botanical name…………Common Name……………Local Names

1-Tamarindus indica………Tamarind……………..Imli

2-Cassia fistula…………Amaltus.

3-Bauninia verigata………Camel’s foot………….Kachnar

4-Poinciana regia………..Flame of Forest ………Gul-e-Mohar

5-Parkinosia roxburgai……VilayatiKikar

FLORAL DIAGRAM

(From Book)



2 MIMOSACEAE

ALTERNATE NAME

It is also known as “Acacia family”.

CLASSIFICATION

DIVISION : ANGIOSPERMS

CLASS : DICOTYLEDON

SUBCLASS: POLYPETALAE

SERIES : CALCIFLORAE

ORDER : ROSALES

FAMILY : LEGUMINOSAE

SUBFAMILY : MIMOSACEAE / ACACIA

GENERAL CHARACTERS

It is the smallest group among the 3 groups of family legume. It contains about 40

genera and 1450 species.

HABITAT

Mostly plants are distributed in tropical and subtropical regions. Great variation

inhabit, usually these trees are perinial or binnial shrubs, some are herbs and climbing.


1. ROOT

Usually, Tap root with side branches, nodules are present.

2. STEM

Usually, Erect and woody stem, rarely herbacious, tannin and gums may also present.

3. LEAVES Usually, Compound, bipinnate, stipule are modified into spines. In many plants leaves

show sleeping movement or after having a shock.

INFLORESCENCE

Mostly, racemose.

FLORAL CHARACTERS

Usually, Complete, bisexual actinomorphic, perigynous, pentamerous.

1. CALYX Usually, 5 sepals, gamosepalous, valvate.



2. COROLLA Usually, 5 petals, polypetalous, valvate aestivation, small size.

3. ANDROCEIUM Usually, numerous stamens, exerted, extrose, basifixed anther.

4. GYNOECIUM

Usually, Monocarpillary, perigynous, unilocular, placentation marginal, many ovules

in locule.

POLLINATION

Usually, cross pollination by insects (entomophilly).

SEEDS Usually, Non-endospermic or with very little endosperm.

FRUIT Usually, It is called legume.

FLORAL FORMULA

+ ,Q , K(5) , C(5) , Aα , G1/


1.WOOD YIELDING PLANTS e.g-prosopis

Acacia species

Albizzia

Xyliaet

2. ORNAMENTALS e.g-Mimosa pudica (chuimoi)

Austratian Acacia

Neptunia

3. FOODER From leaves of prosopis,

Acacia

Dicrostachys e.t.c.



4. SOAP POPS Acacia concinna pods have (soponim), a substance can be used as Soap.

5. CATECHU (KATHA) Piece of hard wood

6. MEDICINAL USE

Katha

Siah Kanta

Entada

Acacia senegal

7. GUMS & DYES

Katha

Safed Babul

Sada Babul

IMPORTANT FAMILY MEMBERS

BOTANICAL NAME…………..COMMON NAME…………….LOCAL NAME

1-Acacia nilotica…………….Gum tree……………..Bauble, Kikar

2-Albizzia lebbek…………….Siris

3-Mimosa pudica……………..Touch-me-not…………..Chhui mui

4-Prosopis glandulosa…………Prosopis……………..Devi

5-Acacia catechu……………..Katha plant

FLORAL DIAGRAM

(FROM BOOK)

3- ROSACEAE

CLASSIFICATION

Division

Class

Subclass

Series

Order

Family: Rosaceae / Rose family.

GENERAL CHARACTERS

It has about 100 genera and 2000 species.

HABITAT



These plants are found growing all over the world 213 species of about 29 genera are

reported from Pakistan.


1. ROOT

Usually, Tap root with its usual branching.

2. STEM

Usually, Green herbaceous, cylindrical, small spines are also present.

3. LEAVES Usually, Simple leaves with or without petiole, Opposite or alternate.

INFLORSCENCE

Usually Racemose

FLORAL CHARACTERS

Usually, Complete, bisexual, actinomorphic, perigynous, pentamerous.

1. CALYX

Usually, Sometime epicalyx may also be present, of variable number, 5 sepals are

present, Gamosepalous, green, pubescent.

2. COROLLA

Usually, 5 petals or multiple of 5 petals, polypetalous, aestivation, imbricate, shape-

rosaceous, full of colour.

3. ANDROCEIUM Usually, Nomerous stamen,ditheous, anther, enerted, extrose, dorsi fixed.

4. GYNOECIUM

Usually, Monocarpillary or multiple capillary with formation of a single compound

pistil. Ovary perigynous, unilocular two or more ovules are present, placentation axile

when the carpels are many and syncarpous

FLORAL FORMULA

+ , Q , K(5) , C(α) , Ax , G1/ (2-5) or x


FRUIT

Economical importance of this family is great in providing the pleasure and welfare of

mankind. Plants of many famous fruits belong to this family for e.g. Apple, pear,



peach, e.t.c. Perhaps they rank 3rd in commercial importance in the temperate, zone

among the families of flowering plants.

ORNAMENTALS A large no. of ornamental plants of this family are grown in parks and gardens the

most widely cultivated plant for this purpose is Rosa. Many others genera are also

grown for their beautiful flowers in homes and gardens.

OTHERS Branches of crataegus and cotoneaster provide excellent walking stick and wood. The

wood of pyruspastia is used for making tobacco pipes. In Asian countries rose petals

are used in making Gul Khand and are also used in extraction of an essential oil, Rose

oil, used as perfume or may be used as eye cleaner in certain diseases.

FAMILIAR PLANTS

BOTANICAL NAME……………….COMMON NAME…………..LOCAL

NAME

Malva silvestis……………………….Apple………………..Seb

Pyrus pyrifolia……………………….Pear…………………Nashpati

Prunus amygdalus………………………Almond………………..Badam

Rosa indica…………………………..Rose………………….Gulab

Prunus persica………………………..Peach…………………Aru

FLORAL DIAGRAM

(FROM BOOK)

4-SOLANACEAE

ALTERNATE NAME

Night shade or Potato family

HABIT AND HABITAT

It is widely distributed in temperate region and very abundant in tropical countries.

The plants are usually herbs or climbing vines but may be shrub.


1-ROOT Tap root and branched

2-STEM Herbacious, erect or underground(Potato)

3-LEAF

Alternate in vegetative and opposite in floral region

FLORAL CHARACTERS



INFLORESCENCE

Cyme sometimes helicoids

1-FLOWER Pentamerous, Bisexual, Regular, Actinomorphic, Hypogynous.

2-CALYX

Five, united sepals

3-COROLLA

Five petals, united, valvate aestivation

4-ANDROCIEUM Five stamens, Inserted on Corolla

5-GYNOECIUM

Bicarpellary, Syncarpous (Carpels fused), Placentaion axile.

6-FRUIT

Capsule Berry or Xanthium.

7-SEED Minute with abundant endosperm.

FLORAL FORMULA

+ , O , K(5) , A5, C(5) ,

ECONOMIC IMPORTANCE

Members of this family provide drugs and food. Some plants are poisonous and other

are ornamental. This family is of great economic importance as it provides food,

fodder, drugs and ornamentals.

1-FOODER

Solanum tuberosum (Potato)

Lycopersicum esculentum (Tomato)

Solanum melongena (Brinjal)

2-CONDIMENTS

Fruit of capsicum

Capsicum frutenscens

3-EDIBLE FRUIT

Physalis (Cherry or Rasbhari)

4-DRUG YIELDING

Atropa belladonna (atropine)

Dotura (Daturine)

Used in severe cold and in eye diseases.

Sap of hanbane is used in dilating the pupils, white cherry is used an nerve tonic.

5-ORNAMENTAL

Cultivated in gardens

Petunaia



Nicotiana

Cestrum Schizanthus

Brunfelsia solanum

6-CIGARETTE MAKING

Nicotiania tobacum (Tobacco)


BOT-NAME……………………COMMON NAME…………………….LOC-

NAME

1-Solanum Tuberosum………………Potato…………………………Aaloo

2-Solanum Melongena………………Bringal………………………..Bengan

3-Lycoperscum Escalentum………….Tomato…………………………Temater

4-Capsicum Annum…………………Red-Pepper……………………..Lal-mirch

5-Petunia Alba…………………..Petunia

6-Solanum Nigrum…………………Black Night shade

7-Datura Alba……………………Thorn apple

8-Nicotiana Tobaccum……………..Tobacco………………………..Tambako

9-Atropa Belladonna………………Deadly night shade

10-Cestrum nocturnum……………..Lady of night…………………..Raat ki Rani

FLORAL DIAGRAM

FROM TEXT BOOK (BIO-XI FAMILY SOLANACEAE )

5-FABACEAE

ALTERNATE NAME

Papilionaceae or Pea family

HABIT AND HABITAT

Plants are herbs, shrubs or trees. Climbers, aquatic plants or xerophytes. World wide

distributed.


1-ROOTS Tap root, branched bearing tubercle containing nitrogen fixing bacteria.

2- STEM Herbecious or woodi, erect or climber.

3-LEAF

Simple or commonly compound alternate, stipulate

FLORAL CHARACTERS



1- INFLORESCENCE Racemose, rarely solitary.

2- FLOWER Bisexual, irregular, zygomorphic, hypogynous.

3- CALYX

Five sepals, united

4- COROLLA

Five petals, usually free.

Corolla is papilionaceous (Butterfly shaped). In this form the petals are 5, one of them

is usually large and clawed. This petal is called standard or “Vexillum” The two

lateral ones, which are free are called as “Wings” and two anterior inner most fuse to

form a boat shaped structure called the “Keel” or “Carina”.

5- ANDROCIEUM

Stamens (9) +1 i.e 9 fuse to form a round sheath around the pistil while tenth is free.

6-GYNOECIUM Monocarpellary, ovary unilocular, ovule numerous on marginal placenta.

7-FRUIT Legume or pod.

8-SEED EX-albuminous.

FLORAL FORMULA

+ , Q , K(5) , C 1+2+(2) , A(9)+1 , G1

ECONOMIC IMPORTANCE

The family is of considerable importance, as a source of high protein food, oil and

forage as well as for ornamental purposes. Chief importance lies in the pulses,

belonging to this family. All types of pulses (Dalls) are actually the seeds of this

family which are rich in protein.

1- FOOD & FORAGE

Cicer arietinum (Gram)

Pisum sativum (Pea)

Lens esculanta (Masure)

Phaseolus aureus (Mung)

Phaseolus mung (Urad/Mash)

Phaseolus vulgaris (kidney bean/Lobia)

Medicago sativa alfalfa (Lusan)

Vicia

Melilotus & Trifolium



2- FURNITURE & BUILDING PURPOSE

Butea

Dilburgia

3- OIL EXTRACTION

Arachis hypogea (Peanut/Moongphali)

4- DYES

Indigofera tinctoria (Neel)

Butea monosperma (Yellow dye)

5-MEDICINAL PURPOSE

Glycyrrhiza glabra (Cough & cold treatment)

Clitoria termatea (Snake bite treatment)

6- ORNAMENTAL PLANTS

Lathyrus

Lupinus

Clitoria

Butea

Abrus precatorious, used by jewellars as weights called “Ratti”.


BOT-NAME……………….COMMON NAME………………..LOCAL-NAME

1- Lathyrus Odoratus………..Sweet pea………………….Matter

2- Arachis Hypogea………….Peanut…………………….Moongphali

3- Cicer Arietinum………….Gram………………………Channa

4- Dalbergia Sisso………….Red-wood…………………..Shesham

5- Pisum Sativum……………Edible pea

6- Sesbania aegyptica……….Sesbania

FLORAL DIAGRAM

FROM TEXT BOOK BIOLOGY-XI Pg # 191

6-POACEAE

ALTERNATE NAME

GRAMINAE/ GRASS FAMILY

HABIT AND HABITAT

The species are most numerous in the tropics but they are also abundant in temperate

region.

This family is monocot (one cotyledon in seed)

Mostly annual or perennial herbs or shrubs.




1- ROOTS Adventitious, fibrous or fascicled.

2- STEM Cylindrical, Conspicuous nodes and hollow, although solid stems are also found as

sugar cane.

3- LEAF Legulate, alternate leaf sheath mostly open sessile, lamina narrow and ribbon shaped.

FLORAL CHARACTERS

1- INFLORESCENCE

Compound spikes.

2- FLOWER Sessile, bracteate, incomplete, bisexual or unisexual and zygomorphic.

3- PERIANTH It is combined structure instead of calyx and corolla. Number 2 or 3 membranous

scales called “ Lodicules”

4- ANDROECIUM Usually 3 stamens, filaments long, free anther versatile.

5- GYNOECIUM Tricarpellary, syncarpous though only one is functional, unilocular, single ovule, style

short 2-3, stigma feather like.

6- FRUIT

Grain or coryposis.

7- SEED

Endospermic, monocotyledonous.

FLORAL FORMULA

+ or O , O or O or O , P2 (lodicules) , A3 or 0 , G1 or 0

ECONOMIC IMPORTANCE

The family poaceae has great importance than any other family of flowering plants.

1- FODDER AND FOOD STUFF

Triticum indicum

Avena sativa

Zea mays

Oryza sativa

Hordeum vulgare

Pennisetum typhoideum

2- SUGAR MAKING

Saccharum officinarum (sugar cane)



3-PAPER MANUFACTURING

Certain species of Grasses

4- VEGETABLES & SOUP DISH

Sugar cane

Bamboo-shoots


BOT-NAME…………………………COM-NAME…………………….LOC-

NAME

Triticum Indicum……………………..Wheat……………………….Gandum

Avena Sativa…………………………Oats

Zea Mays…………………………….Indian corn………………….Makai

Oryza Sativa…………………………Rice………………………..Chawal

Saccharum Officinarum…………………Sugar cane…………………..Ganna

Hordeum Vulgare………………………Barly……………………….Joo

Pennisetum Typhoideum…………………Bajra

Bambusa Arundinacea…………………..Bamboo………………………Banns

Cymbopogon Jawarancuza……………………………………………..Lemon Grass

Cynodon dactylon…………………………………………………..Lawn Grass

FLORAL DIAGRAM

FROM TEXT BOOK BIOLOGY-XI Pg#196)

DOUBLE FERTILIZATION

After pollination, the tube nucleus of the pollen grain forms pollen tube, while

generative nucleus divides into two male (sperm) gametes.

When pollen tube reaches the embryo sac through micropyle, one of the male gametes

fuses w/t egg cell and forms “oospore (zygote)”,it develops into seed. Another male

gamete fuses with definitive nucleus and forms “Endospermic nucleus”, w/c develop

into endosperm of seed or food storage tissue of seed.

Because two times fertilization occurs so it is called “Double fertilization”.

THE FLOWERS

The flower is a modified shoot and meant for sexual reproduction. It is collection of

four different kinds of floral members, arranged in four separate whorls. The upper

two whorls are essential or reproductive whorls whereas lower two are helping or

accessory whorls. The flower is born on an axis which consists of two parts the

pedicel or stalk of flower and the thalamus is swollen end of the axis on which the



floral leaves are inserted. The floral whorls are arranged on the thalamus in a

particular order one just above the other. These four whorls are as follows.

CALYX

It is the first or lower most whorl of the flower, the calyx is generally green is colour.

Each member of calyx is known as sepal. Sometimes sepals become coloured called

petaloid. Such as in gold mohur. The calyx is non essential or accessory part of

flower.

FUNCTIONS

1- Protection of floral bud

2- Assimilation when green in colour

3- Attraction when coloured and showy

4- Modified into papus which helps in dispersal

COROLLA

It is the second non essential floral whorl of flower. It is brightly colored. Each

member of its known as petal. However there is no differentiation of calyx and corolla

in some flowers. It is called perianth.

FUNCTIONS

1- The corolla attracts insects and hence help in pollination.

2- It encloses stamens and carpels.

3- It protect the stamens and carpels from external heat rain and insects attack.

ANDROCIEUM

It is the third essential floral whorl and each member of it is known as stamen. The

stamen is a male reproductive body and consists of filament, anther and connective.

The anther bears four chambers of pollen sacs, each chamber is filled with granular

mass of small cells called pollen grains. Each pollen grain consists of two walls, the

outer exine and inner intine.

FUNCTIONS

It is the male reproductive body and hence possess male gametes which take part in

reproduction.

GYNOECIUM

It is the fourth essential floral whorl and its component parts are called carpals. The

carpel is a female reproductive body, it may be one or more than one, and may be

united or free. Each carpel consists of stigma, style and ovary. The stigma is terminal

end which receives the pollen grain. It may be smooth or hairy and becomes sticky on



maturity, The style is slender projection of ovary, It helps in pollination and later on

dries up. The ovary is swollen basal portion, which encloses minute egg like bodies

called ovules. The ovule possess egg cells.

FUNCTIONS

The gynoecium is a female reproductive body. It possess the egg cells which take

parts in reproduction.

AESTIVATION

It is the arrangement of floral whorls i.e. the sepals or petals in a floral bud, it is of

following types:

(A) VALVATE

The members of a whorl lie close to each other and do not overlap e .g Calatropis.

(B) TWISTED One margin of a floral whorl overlaps that of the next one. It may be clockwise or anti

clockwise e.g. China rose.

(C)VEXILLARY

When petals are five, two internal are overlaped on both margins by two petals, these

two are overlaped by a single largest posterior petal e.g. Pea bean etc.

(D)IMBRICATE

When one of the sepal or petal is internal and other external and each or remaining

one is overlaped on one margin and it overlaps the next one on other margin e.g Gold

mohur .

A. Velvate.

B Twisted

C. Vexillary

D. Imtricate.

INSERTION OF FLORAL LEAVES ON THE THALAMUS

The floral leaves are inserted on the thalamus in a particular order, it is of following

types:

(A) HYPOGYNOUS

In some flowers the thalamus is convex or conical and ovary occupies the highest

position on it. However other floral whorls are inserted below the ovary, such flower

is known as hypogynous and ovary as superior. E.g. Mustard.

(B ) PERIGYNOUS In certain flowers thalamus forms a flattened circular disc due to the fact that sises of

thalamus grows up to the same level. The apex of thalamus is in the middle of the disc

at which gynoecium develops, whereas at the rim or margin sepals, petals and

androecium are inserted. They are round about it and hence are called perigynous,



such as in pea. Sometimes the apex of thalamus grows up in conical shape as in

raspberry. Whereas in some cases the calyx forms a cup shaped structure called calyx

tube such as in wild rose.

(C) EPIGYNOUS In some flowers the concave receptacle surrounds the ovary and is fused with it. The

sepals, petals and stamens apparently arise from the tip of the ovary such ovary is said

to be inferior. E.g. Sunflower, apple, guava, pear etc.

IMPORTANT TERMS TO DESCRIBE A FLOWER

COMPLETE: When all the four floral whorls are present.

INCOMPLETE: When any of the whorl is absents.

BISEXUAL: The stamen and carpel both are present.

UNISEXUAL: The flower possess either stamen or carpel.

STAMINATE: Only stamens are present (male).

PISTILATE: When flower possess only carpels (female).

NEUTER: The stamens and carpels both are absent.

SYMMETRY

+ACTINOMORPHIC

When a flower can be divided into two equal halves by any vertical section passing

through centre.

+ ZYGOMORPHIC

When it can be divided into two similar halves by only one vertical section.

+ IRREGULAR

The flower can not be divided into two similar halves by any vertical plane.

COHESION OF STAMEN

+ MONOADELPHOUS

When filaments are united in a bundle and anthers are free e.g. China rose.

+ DIADELPHOUS

The filaments are united into two bundles and anthers are free e.g. Pea.

+ POLYADELPHOUS

The filaments are united into more than two bundles and anthers are free.

+ SYNGENECIOUS

The anthers are united together and filaments are free e.g. Sunflower.

ADHESION OF STAMENS

+ EPIPETALOUS

The stamens adhere to corolla, wholly or partially by their filaments.

+ GYNANDROUS

When stamens adhere to carpels e.g. Calatropis.



LENGTH OF STAMENS

+DIDYNAMOUS

The stamens are four, two of them short and two long e.g. Nerium.

+TETRADYNAMOUS

The stamens are six but two short and four long e.g. mustard.

GYNOECIUM

+ MONOCARPELLARY

The pistil consists of only one carpel, it is also known as simple pistil e.g. Pea, Bean

+ POLYCARPELLARY

The pistil consists of two or more carpels, it is also known as compound pistil e.g.

Rose.

+ SYNCARPOUS

The carpels are united into one ovary e.g. Mustard.

STIGMA

+ CAPITATE

When stigma is rounded and knob like. Bi, tri or Multified: when stigma is branched

into two , three or many.

+ FEATHERY

When stigma is feather like.

+ FLATTENED

When sitgma is flat.

+ POINTED

When stigma is pointed.

+ LINEAR

When it is long and narrow.

STYLE

+ TERMINAL

When style arise from top of ovary; such as in Mustard.

+ GYNOBASIC

When it arise between the lobes of the ovary from its base;such as in Salvia.

+ PEDICILLATE

When flower is born on a stalk or pedicel. (STALKED)

+ SESSILE

When stalk is absent

+ BRACTEATE

When flower is developed in the axil of a bract

+ EBRACTEATE

When bract is absent.



+ DIMEROUS

When each floral whorl has two floral leaves (Dicot)

+ TRIMEROUS

When floral whorl has three floral leaves (Monocot)

+ TETRAMEROUS

When each floral whorl has four floral leaves; and so the pentamerous Dicots)

CALYX

+ PETALOID

The calyx having other then green colour.

+ CAMPANULATE

Sepals fused to form bell shaped structure.

+ POLYSEPALOUS

When sepals are free from one another.

+ GAMOSEPALOUS

When sepals are fused or united with one another.

PETALS

+SEPALOID

The petals are green in colour.

+CRUCIFORM

Petals are arranged in form of a cross.

+POLYPETALOUS

When petals are free from one another.

+GAMOPETALOUS

When petals are united with one another.

+PERIANTH

When calyx and corolla can not be distinguished with one other due to similar shape

and colour.

PERIANTH

+SEPALOID

When perianth leaves are green.

+POLYPHYLLOUS

When perianth leaves are free from one another.

+GAMOPHYLLOUS

When perianth leaves are fused.

FLORAL FORMULA

The floral formula is represented by various symlols. The symbols used in floral

formula are as follows.



SYMMETRY OF THE FLOWER

Zygomorphic = +

Actinomorphic = O

SEXUALITY

Bisexual = Q+

Unisexual (male)

Unisexual (female)

Neuter =

PERIANTH

Perianth = P

Polyphyllous = Pn n=number of perianth leaves.

Gamophyllous = (n) “ “ “

CALYX

Epicalyx = Epi K

Petals = C

Calyx = K

Polypetalous = Cn,

Polysepalous = Kn, n= number

Gamopetalous = C(n)

Gamosepalous = K (n) of sepals

ANDROECIUM

Androecium = A

Androecium free = An n= number of stamens

Androecium United = A (n)

Epipetalous = C-A

GYNOECIUM

Gynoecium = G

Apocarpous = Gn

Syncarpous = G (n)

Ovary inferior = G

n= number of carpels

Ovary Superior = G

FLORAL DIAGRAM

The features of flower in flora formula are represented by symbols, while in floral

diagram by the diagram of its various floral leaves alongwith actual number and



position.

MOTHER AXIS: It is represented by a Dot above the floral diagram. It actually

shows the position how a flower is born. The position of it can be seen from

upperside. It may be between two adjacent sepals or a single sepal.

PLACENTATION

It is the arrangement of placenta which are cushion like ridges in the ovary, The

placenta bear ovules. In simple ovary placentaion is marginal, whereas in compound

ovary it may be parietal, axile, free central, basal and superficial.

(A) MARGINAL

In a simple ovary or monocarpellary pistil, the ovules are arranged along the fused

margins, these margins forms a cushion like tissue called placenta

(1) PHYLUM PORIFERA

Porous body

CaCO3 Silica Skeleton

Asymmetrical

Amphiblastula larva

Diffuse cellular organization

Spongocoel body cavity

(2) PHYLUM CNIDARIA

Radially symmetrical

Body cavity “Coelentron”

Pnedoblast – Defensive cells

Diploblast (Ecto + Endoderm)

Middle non-cellular layer “Mesoglea”

Larva – Planula Larva

Morphologically

a- Medusa = Umbrella like

b- Polyp = Rod shaped

(3) PHYLUM PLATYHELMINTHES

Flatworms

Totally Parasite

Flat or Ribbon shaped

Excretory organs – Proto nephridia (Flame cells)

Aeoelomate (Absence of body cavity)

It is the first phylum containing triplo blastic animals

Usually Hermaphrodites

Planaria is the only free living member

High fertility rate



Bilaterally Symmetrical

(4) PHYLUM ASCHELMINTHES (NEMATODA – ROUND WORMS)

Totally parasitic including 50 human parasite

Bilaterally symmetrical with cylindrical body

Two openings (Mouth & Anus)

Psudocoelomates

Common diseases – Ascariasis, filiariasis (elephantiasis), hook worm infection.

(5) PHYLUM ANNELIDA (SEGMENTED WORMS)

Metamers (External segmentation)

Septae (Internal segmentation)

Setae (Locomotary organs) or cheata

Digestive, excretory, nervous, reproductive system well developed.

Respiration through diffusion

Blood is red with a closed type of circulatory system (with many pulsatile hearts)

CLASS POLYCHEATA

Setae with Parapodia

Separate sexes

Sabella (Peacock worm), Nereis (Clam worm)

CLASS OLIGOCHEATA

Setae without Parapodia

Pheretima (Earth worm)

CLASS HIRUNDINIA (LEACHES)

Free living, Ecto or Endo parasite

Contains a Enzyme hirudin which prevents blood clotting

(6) PHYLUM MOLLUSCA (SOFT BODIED ANIMAL)

Second largest phylum

Largest invertebrate – Gram squlds

External hard covering calcium carbonate shell

A grinding structure radula is present in the buccal cavity

Thin membraneous covering of the body – mantle

Respiration through gills

Locomotary organ a mascular foot

Larva – Trocophore larva

CLASS GASTROPODA



A phenomenon torsion is present in which the animal body rotates at the angle of

180?

Example: Pila

CLASS BIVALVIA

Second largest class of mollusca

Shell consist of two parts and attached with eachother by hinge joint

Common examples: Unio, mytilus and pearl oysters

CLASS CEPHALOPODA

All members are marine

Locomotary organ foot transformed into suckers which bears tentacles and arms

Example: Sepia (cuttle fish), loligo (squids), octopus (devil fish)

Shell is absent in octopus

(7) PHYLUM ARTHROPODA ( JOINTED LEGS)

Largest phylum

One million species

Metamerically segmented animals

Blood filled cavity hoemocoel is present

Blood without haemoglobin (white)

Respiration: Gills, Trachea or Book lungs

Excretory organs malphigian tubules

Nervous system well developed

Compound erges with sharp vision

Metamorphosis = developmental changes which transforms a larva into its developed

adult form

Incomplete metamorphosis = egg → nymph → adult e.g. cockroach

Complete metamorphosis = ® egg ® larva ® pupa ® adult e.g. Butterfly, common,

housefly and mosquito

Moulting (ecdysis)

Changing over of old exoskeleton and formation of a new one

Apiculture => Farming of honey bees

Sericulture => Farming of silk worms

CLASS MEROSTOMATA

Limulus (king crab)

CLASS ARCHINIDA (SPIDER LIKE)

Group of Spiders & Scorpions

Respiration through book lungs



Four pair of walking legs

CLASS CRUSTACEA

Class of prawns, shrimps, lobsters, crabs

Two pairs of antenae, one pair of mandible and two pair of maxilla

Exoskeleton a large plate of carapase

Sacculina is the only parasitic member

CLASS MYRIAPODA

Class of millipedes and centipedes

Body is divided into similar multiple segments

CLASS INSECTA OR HEXAPODA

Largest class (eight lakhs & 50,000 members)

Study of insects is called entomology

Three pairs of walking legs

Pterygota (insects with wings)

Apterygota (insects without wings)

Social insects: Ants, termites, honey bees

(8) PHYLUM ECHINODERMATA (ANIMAL WITH SPINY SKIN)

Marine animals

Radially symmetrical

Pentamerous body

Water vascular system is present

Locomotary organs are tube feets = External openings of the water vascular system

Exoskeleton is made up of calcarious plates in the form of spines

Power of regemeration is very great

Phylum echinodermata, hemichordata & chordate posses common ancestor

Bipinnaria larva is present

Common e.g. Sea Star (Star fish, Brittle star, Sea dollar, Sea urchins, Sea cucumbers.

(9) PHYLUM HEMICHORDATA (ANIMAL WITH HALF NOTOCHORD)

Notochord in future = Vertebral column + Skull

Dorsal nerve cord = Brain and Spinal cord

Pharengeal gill slits <–>Aquatic animals = gills

-> Terrestrial = Internal neck structures

Only 90 species are present

Larva is tornaria larva

Open circulatory system



(10) PHYLUM CHORDATA

GROUP ACRANIATA

Brain without any covering or skull

SUB-PHYLUM UROCHORDATA

Also known as tunicates

Body is enclosed in a sac tunic

Only embryonical stages show chordate characters

SUB-PHYLUM CEPHALO CHORDATA

Embryonic as well as adult both forms show typical chordate characters

GROUP CRANIATA OR VERTEBRATA

Brain and spinal cord is enclosed in a hard covering skull & vertebral column

respectively

SUB-PHYLUM AGNATHA (ANIMALS WITHOUT JAWS)

Also known as cyclostomes or jawless fishes

Totally parasitic

Teeth are present in the form of rings

Common e.g. Hag fishes, lamprey

SUB–PHYLUM GNATHOSTOMATA (ANIMAL WITH JAWS)

Teeth may be present or absent

Amphibians and bird lack teeth

Fishes, reptiles, mammals do have teeth

1. SUPER – CLASS PICSES (FISHES)

Study of fish is known as echthylogy

SUB – CLASS CHONDRICHTHYES (CARTILAGENOUS FISHES)

Endo skeleton is cartilaginous (soft boned)

Exoskeleton – Placoid scales

Fins are heterocircle (different size and shaped)

Gills without any covering

Common example (Sharks, Squids, torpedo, electric ray)

Scolidoen (dog fish) – Small Shark

SUB – CLASS OSTEOCHYTHES (BONY FISHES)

Exoskeleton cycloid or ctenoid scales

Operculum is present (covering of gills)



Fins are homocircle (Same size and shape)

Lung fishes are included in order dipnoi.

2. SUPER CLASS TETRAPODA

1. CLASS AMPHIBIA

Exoskeleton is absent

Respiration by lungs, gills or skin

Fertilization is external

Cold blooded

Having the characteristics of hibernation & aestivation

Common e.g. Toads, frogs, salamanders etc.

2. CLASS REPTILIA

Included in group amniota due to the presence of amnion in eggs

Fertilization is internal

Exoskeleton is made up of thick horny scales

Important members are snakes, turtles, lizards, crocodiles and alligators

Venom → Snake poison

Fangs → sharped and curved teeth of snake

3. CLASS AVES (BIRDS)

Study of birds is called ornithology

They posses hollow bones (Pneumatic bones)

Sound producing organ “Syrinx” is present instead of larynx.

Teeth totally absent.

SUB CLASS RETITA (FLIGHT LESS BIRDS)

E.g. Penguin, Kiwi, Ostrich.

Ostrich → Largest Bird.

SUB CLASS CARNIATAE (FLYING BIRDS)

Wings with interlocking system.

Common e.g. Peacock, Seagulls, Kites, Falcon etc.

Archeopetryx → Intermediate specie between reptiles and birds.

4. CLASS MAMMALIA

Presence of mammary glands and hairs.

A muscular organ diaphragm, which separates thoracic cavity from abdominal cavity.

Teeth are present with different size and shape (heterodont).

a- Incissors → for biting and cutting purpose

b- Canives → Tearing purpose



c- Pre-Molars -> For grinding and holding purpose

d- Molars -> For grinding and holding purpose

SUB CLASS PROTOTHERA (EGG LAYING MAMMALS)

Also called monotremous.

Two genera with 3 species

Oviparous.

Common urogenital opening Cloaca is present.

External ear is absent.

It is a connecting link between reptiles and true mammals. e.g. spiny anteater, duck

billed platypus.

SUB CLASS METATHERIA (POUCHED MAMMALS)

Marsupials

Give birth to live young ones.

Special pouch like bag is present in the ventral side of female.

This pouch is known as marsupial.

Common e.g. Kangaroo, Kuala bear, Opossums.

SUB CLASS EUTHERIA (PLACENTAL ANIMALS)

95% of mammals are included in this group.

Viviparous.

Placenta → connecting link between mother and fetus.

Common e.g. Camel, donkey, elephant, bat, whale, dolphin.

Markhor is the national animal of Pakistan also known as Wild goat

INTRODUCTION

Includes all eukaryotic multicellular and chlorophyllous living organisms, which have

cell wall made up of true cellulose.

Majority of members are autotrophic but few are parasite e.g.: “Cuscuta”

They have localized growth, regions of growth lying primarily at the extremities that

is root and stem apices.

CLASSIFICATION OF KINGDOM PLANTAE

Kingdom planatae is divided into tow sub-kingdom on the basis of presence or

absence of vascular tissue (xylem and phloem).

A – SUB-DIVISION – BRYOPHYTES (NON-VASCULAR)

Class Hepatica (Liverworts)

Class Musci (Mosses)

Class Anthroccrota (Hornworts)



B- SUB-DIVISION – TRACHEOPHYTES

Class Psilopsida (Psilopsids)

Class Lycopsida (Club Mosses)

Class Sphenopsida (Horse Tails)

Class Pteropsida (Ferns)

ClassSpermopsida (Seed Plants)

SUB –DIVISION BRYOPHYTA (AMPHIBIAN PLANTS) OR (NON-

VASCULAR PLANTS)

Absence of lignin-fortified tissue to support tall plants on land.

Members of this sub-division usually sprawl horizontally as mats over a large surface.

Always have a low profile (1-2cm-20cm tall).

Regular heteromorphic alternation of generation is present w/t gametophytes

dominancy (Gametophytes large and long lived).

Sporophyte stage of bryophytes is generally smaller and shorter lived, and it depends

on gametophyte for water and nutrients.

The diploid sporophyte produces haploid spores via meiosis in a structure called

“sporangium”

The tiny, spores, protected by sporopollenim, disperse and give rise to new

gametophytes.

All members of bryophytes need water to reproduce.

Gametes produce within reproductive structures “Gametangia” (Male-Antheridia and

Female-Archer-gonium)

Antheridium produces flagellated sperm while female archegonium contains one egg

(ovum).

Fertilization occurs w/t in the archegonium

Zygote develops into an embryo within the protective jacket of Archegonium.

Windblown spores disperse the speies.

All bryophytes belong to Silurian/Devonian period (345-395Million yrs. Ago.)

ADAPTATION OF BRYOPHYTES TO LAND HABITAT

All Bryophytes show amphibious form of land plants. Following are main adaptations

exhibited by them.

a. Rhizoid for water absorption

b. Conservation of water

c. Absorption of CO 2

d. Heterogamy

e. Protection of reproductive cells

f. Formation of embryos

CLASSES OF BRYOPHYTES



1-MUSCI (MOSSES)

Plants grow in a tight pack, in the form of mat, in order to hold one another up.

Mat of moss possess spongy quality and enables it to absorb and retain water.

Rhizoids are elongated cells or cellular filaments of mats which grip the substratum.

Photosynthesis occurs in upper part of the plant w/c has many small stem like and leaf

like appendages. E.g Funaria.

2-HEPATICAE (LIVERWORTS)

Usually present in tropical areas

Plant body is divided into lobes somewhat of the lobed liver, of an animal.

These plants are less fimiliar than Mosses.

E.g Marchantia

3- ANTHROCERATAE:- (HORNWORTS)

These plants resemble w/t liverworts, but are differentiated by their sporophytes

plants.

Sporophyte are elongated capsules that grow like horn from mat like gametophyte.

Sporophyte has stomata and chloroplast, performs photosynthesis

Sporophyte plant can survive even often the death of gametophyte due to presence of

Meristem.

Meristem is a specialized tissue, which keeps on adding new cells in sporophyte plant.

Hornworts are the most advanced members of bryophytes.

E.g Arthroceros

SUB-DIVISION TRACHEOPHYTA (VASCULAR PLANTS)

Main characters are as follow,

Conducting vessels Xylem and Phloem are present in plant body.

A protective layer of sterile “Jacket” cells around reproductive organs are present.

Multicellular embryos retained within the archegonia.

On aerial parts protective covering “Cuticles” is present w/c prevents excessive loss of

water during hot climate.

In life cycle Sporophyte stage is dominant.

CLASSES OF TRACHEOPHYTES

1-PSILOPSIDA

These are the fossil representatives of the vascular plants, belonging to “Silurain

period” and “Devonian Period”

Sporophytes are simple dichotomously branching plants.

True leaves and true roots absent.



Underground stems that contain unicellular rhizoid similar to root hairs.

The aerial stems are green and carry out photosynthesis.

Lacking secondary growth due to absence of “Cambium”

Reproductive structure “Sporangia” develop at the tips of some of the aerial branches.

Meiosis produces haploid spores, within the sporangia.

E.g. Rhynia, Psilotum Temesipteris

A) RHYNIA (FIRST VASCULAR PLANT)

One of the most primitive vascular plant

It is an extinct genus, was named often the village “Rhynia of Scotland where the first

fossils of Rhynia were discovered.

It belongs to Devonian period, which started about 400 million years ago.

The fossils of this plant are so well preserved that the stomata are still intact.

STRUCTURE

The plant body (Sporophyte) was simple.

It consisted of slender, dichotomously branched creeping rhizome, bearing erect,

dichotomously branched aerial stem.

Instead of roots, rhizoids were given out from rhizome.

The aerial branches were leaf-less having terminal fusiform naked sporangia.

MICROSCOPIC STRUCTURE

The internal structure of branches show a solid central core of vascular tissues

surrounded by Cortex.

The outer most layer is Epidermis having stomata.

The vascular tissue is differentiated into centrally placed xylem and surrounded

phloem

(FIGURE 9.06(a) Reconstruction of Rhunia) TEXT BOOK BIO-XI Pg# 170

B) PSILOTUM AND TEMESIPTERIS (LIVING SPECIES OF PSILOPSIDA)

Sporophyte plant produce spores, which give rise to minute subterranean

gametophytes.

Each gametophyte bears both female reproductive organ Archegonia and male

reproductive organ Antheridia w/c produce both egg and sperm respectively.

As a result of fertilization a diploid zygote is formed which develops into sporophyte

plant.

Sporophyte stage of life cycle is dominant, but haploid gametoplyte stage is still

relatively large.

EVOLUTION OF LEAF

The leaf is the most important organ of a green plant because of its photosynthetic

activity. Leaves are of tow types



1. Single veined leaves- Contain only one vein

2. Poly veined leaves- Contain two or more veins

1- EVOLUTION OF SINGLE-VEINED LEAF

It is assuming that a thorn like out growth emerged on the surface of the naked stem.

With an increase in size of the leaf, the vascular tissues were also formed for the

supply of water and support to the leaf.

Another possibility is that a single veined leaf originated by a reduction in size of a

part of the leafless branching system of the primitive vascular plants.

2-EVOLUTION OF POLY-VEINED LEAF

These are the evolutionary modifications of the forked branching in the primitive

plants.

The first step in the evolution of this leaf was the restriction of forked branches to a

single plane.

The branching system become flat.

The next step in the evolution was filling the space b/w the branching and the vascular

tissues.

The leaf so formed looked like the webfoot of a duck.

(Fig#9.7-9.8From Text. Book)

2-LYCOPSIDA(THE CLUB MOSSES)

These plants belong to middle Devonian and carboniferous periods.

They were very large trees that formed the earth’s first forests.

Only five living genera of this group are present.

Two members, selaginella and lycopodium are common in many areas of Pakistan

These plants have true branched underground roots.

True leaves also present w/c have arisen as simple scale like outgrowth (emergence)

from the outer tissues of the stem.

Specialized reproductive leaves bearing sporangia on their surfaces, are present, such

type of leaves are known as “Sporophylls”.

In some members, the sporophylls are collected on a short length of stem and form

cone like structure “Strobilus”.

The cone is rather club-shaped; hence name “Club-Mosses” for the lycopsids.

Gametophytes plant may be homosporous or heterosporous .

A) HOMOSPOROUS GAMETOPHYTES

Spores produced by sporophyte plant are all alike, and each give rise to a

gametophytes that bear both archegonia (female reproductive structure) and antheridia

(male reproductive structure)

Example Lycopodium (Running pine or ground pine)

B) HETEROSPOROUS GAMETOPHYTES



Sporophyte (2n) plant produces two types of sporangia, which produced different

kinds of spores.

One type of sporangium produces very large spores called “Megaspores,” which

develop in female gametophytes bearing archegonia.

Other type of sporangium produces small spores called “Microspores, which develop

into male gametophytes bearing antheridia.

That’s mean sexes are separate in the gametophytes generation (Heterosporous).

Example: Selaginella.

EVOLUTION OF SEED

Seeds are evolved from primitive spores.

STEPS OF EVOLUTION

1. PRIMITIVE SPORES

All spores of specie are nearly identical in size, structure and function.

2. HETEROSPORES

There are many vascular plants that form two kinds of spores, these plants are said to

be “Heterosporous” and spores are called “Heterospores.”

These spores on germination give rise to two different types of plants.

A) MALE SPORE: It produces sperm forming gametophyte plant.

B) FEMALE SPORE: It grows into egg forming gametophyte.

3. PROTECTION OF HETEROSPORES

The two different kinds of spores are formed in two different kinds of sporangia.

Various enveloping structures develop in order to protect these spores.

Certain fern like plants first developed seed like structures, each of their sporangia,

containing one or more female spores, was surrounded by little branch like out growth

structure forming “Integument.”

4. PERSISTANCE OF FEMALE SPORES

Instead of being shed from the sporangium, the female spores are retained and

protected inside the integument.

The female spore develops into a tiny female gametophyte protected by the

integuments.

5. FORMATION AND STRUCTURE OF SEED

Seed is formed as the result of fertilization of male spore with this protected female

spore.

Immature seed is called “Ovule.”

Ovule is protected by integuments and it contains great quantities of food.



Ovule not only protects the female gametophyte from the environment but also

provides food for the new off springs that is produced when the seed matures and

germinate. The development of seed has given the vascular plants better adaptations

to their environment.

3. SPHENOPSIDA (THE HORSE TAILS)

These plants belong to late Devonian and Carboniferous period.

Only one living member “Equisetum” commonly called “Horse-tail” exists today.

Ancient sphenopsids were large trees but now most of these are small (Less than one

meter).

Coal deposits of today was formed from the dead bodies of those plants.

These plants possess true roots, stems and leaves.

Stems are hollow and are jointed, whorls of leaves occur at each joint.

Secondary growth absent, because modern species do not possess cambium.

Spore are born in terminal cones (Strobili) and all are alike (i.e. plants are

homosporous) and give rise to small gametophytes that bear both archegonia and

antheridia (i.e. the sexes are not separate).

4. PTEROPSIDA (THE FERNS)

These plants belong to Devonian and Carboneferous Period and then decline in

Paleozoid Period.

They are very well developed plants having vascular system with true roots, stem and

leaves.

Leaves are probably arisen from flattened web branched stems. They are large and

provide much greater surface area for photosynthesis.

Leaves of Ferns are sometimes simple, but more often they are compound, being

divided into numerous leaflets.

In most modern ferns of temperate regions, the stems are prostrate on or in the soil,

and the large leaves are only part normally seen.

SPOROPHYTIC STAGE

The large leafy plant (fern) is diploid sporophytic phase.

Spores are produced in sporangia (Reproductive structure) located in clusters on the

underside of some modified leaves “Sporophyll.”

Most modern ferns are homosporous i.e. all these spores are alike.

Vascular sporophytes can live in drier places and grow bigger.

GAMETOPHYTE STAGE

After germination, the spores develop into gametophytes that bear both archegonia

and antheridia.



These gametophytes are tiny (less than one centimeter wide), thin and often more or

less heart-shaped.

Free-living, non-vascularized gametophytes can survive only in moist places, their

sperms are flagellated and water is required for fertilization.Young sporophyte

develops directly from the zygote without passing through any protected seed like

stage.

(LIFE CYCLE OF FERN-TEXT BOOK PAGE # 166 NEW ADDITION)

ALTERNATION OF GENERATION

In Kingdom Plantae, life cycle of many plants is completed in two stages or

generations known as Gametophyte and Sporophyte.

The two generations normally differ from each other in morphology, reproduction and

number of chromosomes.

The gametophyte is haploid and reproduces sexually by forming the gametes, while

the sporophyte is diploid and reproduces a-sexually by forming the spores.

The two generations regularly alternate with each other and therefore, the

phenomenon is called “Alternation of generation” (Heteromorphic).

In Bryophytes, the main plant itself is the Gametophyte while the sporophyte is

reduced.

In Tracheophytes, the main plant is “Sporophyte” and the “Gametophyte” is reduced.

5. SPERMOSIDA (THE SEED PLANTS)

First appeared in late Devonian and became dominant in Carboniferous Period.

Gametophyte stage is even more reduced than in the ferns, and non-photosynthetic or

free-living.

The sperms of most modern species are not independent free-swimming flagellated

cells.

Young embryo, is enclosed within a seed coat and can remain dormant for long

periods.

Spermosida can be divided into two main sub-groups, which are as follows:

i) Gymnosperms

ii) Angiosperms

I) GYMNOSPERM These plants have naked seed because ovules are not covered by ovary i.e. fruit is

absent.

Sub-divisions of Gymnosperms are

a) Cycads

b) Gnetae

c) Ginkgo

d) Conifers



A) CYCADS’

They have arisen from the seed ferns.

These plants appeared in “Permian Period” and Mesozoic Period and declined in

Cretaceous Period.

They possessed large palm like leaves with short height stems.

Living species commonly found in tropical regions and also known as “Sago Palms.”

Nine living genera with over a hundred species exist today.

Cycads and its relatives.

B) GINKGOAE

Mostly contains extinct species, only one living specie, “the Ginkgo” which is also

known as “Maiden Hair Tree.”

Ginkgo often planted as lawn tree.

E.g: Ginkgo Biloba.

C) CONIFERS

Most familiar and best-known group of gymnosperms.

Leaves are small evergreen needles or scales with an internal arrangement of tissues.

Reproductive organs are cone like modified leaves.

E.g: Pinus.

PINUS

This plant belongs to Gymnosperms. It includes about 90 species.

HABIT AND HABITAT

It is distributed world-wide mostly in northern hemisphere. 30 species are found in the

Himalayas. Some are reported in the planes of Punjab.

MORPHOLOGY

The pinus plant belongs to the “Sporophytic Phase.”

It is a tall tree, pyramidal in form and gives a conical appearance and therefore

commonly grouped under “Conifers.”

It is well differentiated into stem, root and leaves.

STEM

It is erect, cylindrical, solid and covered with thick, rough and brownish bark. The

branches are dimorphic,

Branches of unlimited growth or long shoot.

Branches of limited growth or dwarf shoot.

ROOTS

Underground root system is formed by “Tap Roots” which disappear early and only

lateral roots persist later on.



LEAVES

It bears two types of leaves (dimorphic condition)

a) Scale leaves

b) Foliage leaves

A) SCALE LEAVES

Thin, membranous small scale like structures.

Provide protection and do not help in photosynthesis.

B) FOLIAGE LEAVES

Only develop on dwarf shoots.

Number of foliage leaves is fixed for particular specie.

Each leave is needle shaped, simple green therefore also known as “Needles.”

They have smooth surface and are evergreen and persistent.

LIFE CYCLE OF PINUS

The adult plant of Pinus represents the “Sporophytic Phase” of life cycle.

The sporophytic plant body of pinus reproduces asexually by means of spores and

after passing through “Gametophytic Phase” of the life cycle again produce

Sporophytic plant, showing distinct Alternation of Generation.

1. SPOROPHYTIC PHASE

The sporophytic plants of Pinus are mostly monoecious i.e. male and female cones are

found on same plant.

Special reproductive organs called “Cones,” developed on it.

A) MALE CONE OR O-STROBILUS

The male cones occur in clusters near the end of long branches at the place of dwarf

shoot. (Dwarf shoots are replaced by male cone).

Each male cone is simple ovoid structure 3-4 cm in length.

It has got single centrally located cone axis around which are arranged spirally, many

scaly microsporophylls (60-135).

Each microsporophyll has an expanded triangular central part and a stalk like base.

Each microsporangium, which is born on the lower side bears numerous “Pollen grain

mother cells.”

When the microsporangium matures, on its lower side a horizontal slit is formed

through which numerous Pollen grains are liberated and dispersed by wind.

Each pollen grain is winged structure and yellow in colour.

B) FEMALE CONE OR O-STROBILUS

The female cones are developed laterally in the axis of scale leaves.



The female cones are much bigger, woody, dry and hard structure.

The young female cone is reddish green structure. Each female cone consists of a

central axis to which are attached the “Megasporophyll.”

Each megasporophyll on its surface has two ovules.

Each ovule is orthosporous and consists of a central mass of tissue, surrounded by a

single integument, made up of 3 layers.

The integument bears a wide gap, the microphyle.

Within the megasporangium, megaspore mother cells are present, which undergoes

reduction division to produce a “Megaspore.”

Only one megaspore is functional, however the other three degenerate.

2. GAMETOPHYTE PHASE

The spores are the units of gametophytic phase of life cycle.

In case of Pinus the spores are of two types, microspores and megaspores.

A) MALE GAMETOPHYTES

Microspore is a unit of male gametophyte.

Each microspore or pollen grain is a unicellular body, covered with an outer layer,

“Exine,” thick and heavily culticularized, while the inner layer, the “Intine” is very

thin.

The Exine forms the balloon shaped wings on either side, which help in pollination.

The microspore is at this, four celled stage (consisting of one generative cell and two

prothalial cells and a tube cell).

B) FEMALE GAMETOPHYTE

The Megaspore is the first cell of female gametophyte.

The functional megaspore increases in size and forms a complete cellular female

gametophyte, also known as “Endosperm.”

The “Archegonia” are formed towards micropylar side.

The cells of the endosperm or Archegonia initial cell divides and forms the central

cell.

The central cell forms the venter canal cell and a large egg cell.

POLLINATION

In case of Pinus, Pollination is effected by wind (Anemophyllous).

FERTILIZATION

1. The pollen grains reach the apex of the Archegonium.

2. The pollen tube carrying the two male gametes and the tube nuclei comes in contact

with the archegonium.

3. The tip ruptures, discharging its contents into the egg.



4. One of the male gamete fuses with the egg nucleus and unites forming the oospore

or zygote.

5. The second male gamete along with the tube and tube nuclei disintegrate.

PINUS SEED

Fertilized ovules get transformed into seeds.

Seeds are small elongated and winged.

GERMINATION OF SEED

The seed undergoes into a condition of dormancy when the conditions are favourable,

the seed absorbs moisture and the embryo resume growth.

STRUCTURE OF OVULE

Ovules are female part of flower, form seed after fertilization.

Microscopic study of an ovule reveals following structural features of an ovule.

1. FUNICLE

It is slender stalk of ovule through which it attaches to the placenta.

2. HILUM

It is the point of attachment of the body of the ovule to its funicle.

3. RAPHE

In the inverted ovule, the funicle continues beyond the hilum along side of the body of

the ovule forming a sort of ridge, which is called the “Raphe.”

4. CHALAZA

The distal end of the raphe, which is the junction of integuments and the nucellus is

called the “Chalaza.”

5. NUCELLUS

It is the main body of ovule.

6. INTEGUMENTS

Nucellus is surrounded by two coats called the “Integuments.”

7. MICROPYLE

It is the small opening at the apex of integuments.

8. EMBRYO-SAC



It is a large, oval cell lying embedded in the nucellus towards the micropyle end. It is

the most important part of the ovule as it bears the embryo. It is further developed,

and in the mature embryo sac following cells can be seen:

A) EGG APPARATUS

It is the group of three cells lying towads the micropyle.

One cell of the group is the female gamete, the ovum/egg, and the other two are called

“Synergids.”

The ovum or egg-cell on fertilization gives the embryo, synergids get disorganized

soon after fertilization.

B) ANTIPODAL CELLS This is the group of three cells lying at the opposite end of egg apparatus. These have

no definite function.

C) DEFINITIVE NUCLEUS

In the middle of the embryo-sac there is a distinct nucleus known as a definitive

nucleus, which is the fused product of the two polar nuclei.

STRUCTURE OF POLLEN GRAIN

Pollen grains are male part of flowers, and are contained in the “Pollen-Sac.”

They are very small in size, usually varying from 10 to 200 μm.

Microscopic study of a pollen grain shows following features:

1. EXINE

It is the outer coat of the pollen grain.

It is tough, cutinized layer, which is often provided with spinous out growths or

markings of different patterns, sometimes smooth.

It has one or more weak slits or pores called “Germopores.”

2. INTINE

It is the inner coat of the pollen grain.

It is thin, delicate, cellulose layer lying internal to the exine.

During fertilization in time grows to form pollen-tube.

3. INTERNAL STRUCTURE

Each pollen grain contains a bit of cytoplasm on a nucleus.

During germination of pollen grain nucleus further divides to form a “Tube Nucleus,”

and a smaller one the “Generative Nucleus.”

The generative nucleus soon divides into two male gametes.

MAIN FUNCTION OF LYMPHATIC SYSTEM



All body tissues are bathed in a watery fluid derived from the blood stream. This

intercellular or tissue fluid is formed when blood passes trough the capillaries. The

capillary walls are permeable to all components of blood except the R.B.C’s & blood

proteins. The fluid passes from the capillary into the intercellular spaces as the inter-

cellular or tissue fluid. About 85% of the tissue fluid returns into the blood at the

venous end of capillary. The rest 15 % of tissue fluid drains into lymphatic capillaries

as lymph along with W.B.C’s, cell debris & micro organism like Bacteria , are

transported back to the heart through lymphatic system.

COMPONENTS OF LYMPHATIC SYSTEM

Lymphatic System Consists of

1. Lymph

2. Lymphatic tissues

3. Lymphatic vessels or Lymphatics

4. Lymph nodes (type of lymphatic tissue)

DETAILS OF COMPONENTS

1. LYMPH

DEFINITION “Lymph is the name given to the tissue fluid once it has entered a lymphatic vessel.

OR It can be defined as “Colour less body fluid that contains lymphocytes (agranular

WBC’S), small proteins & fats”.

EXPLANATION Lymph is a medium of exchange between blood & body cells. It takes the fluid

substances from cell of tissues & intercellular spaces, which cannot penetrate the

blood capillaries.

2.LYMPHATIC TISSUES

DEFINITION “Lymphatic tissues are a type of connective tissues that contain large no. of

lymphocytes”

ORGANS THAT CONTAIN LYMPHATIC TISSUES

Lymphatic tissue is organized into following structures (organs).

Lymph nodes

Thymus

Spleen

Tonsils

Some of the patches of tissues in vermiform appendix & in small intestine.



FUNCTION

Lymphatic tissue is essential for immunologic defenses of the body against viruses &

bacteria.

3. LYMPHATICS

DEFINITION

Lymphatic vessels or lymphatics are blind tubes that assist the cardiovascular system

in removal of tissue fluid from tissues spaces of the body, the vessels then return the

fluid to the blood.

AREAS WHERE LYMPHATIC ARE NOT PRESENT Lymphatics are present in all tissues & organs of the body except.

Central Nervous System

The eye ball

Internal Ear

Epidermis of Skin

Cartilage & bone

TYPES Two Types of Lymphatics are there:-

SMALL - LYMPH CAPILLARIES

LARGE - LYMPH VESSELS.

1. LYMPH CAPILLARIES

DEFINITION “Lymph capillaries are a network of thin walled, anastomosing, microscopic vessels

which are closed towards the tissue sinuses & drain the Lymph from tissues.”

2. LYMPH VESSELS

DEFINATION

The capillaries are in turn drained by lymph tubes having larger diameters & beaded

appearance, called the Lymph vessels.

These vessels contain smooth muscles in them as well as Internal valves to prevent the

back flow of Lymph. The Lymph circulates through the Lymph vessels by the

contraction of surrounding skeletal muscles in one direction (towards the heart). These

vessels converge into collecting ducts i.e right

Lymphatic duct & thoracic duct that drain into large veins at the root of neck.

4. LYMPH NODES



DEFINITION “Lymph nodes are lymphoid tissue which are present through out the course of

Lymphatics, through which the lymph must passes”

INTERNAL STRUCTURE

Each node consists of a thin, fibrous, outer capsule & an inner mass of lymphoid

tissue.

AFFERENT VESSELS Several small Lymphatics which carry the lymph into the lymph node are referred to

as “Afferent vessels.”

EFFERENT VESSEL

A single large vessel which carry the lymph away from the node is called “Efferent

vessel”

FUNCTION Lymph nodes act as filters that trap the microorganisms & other foreign bodies in the

lymph. The Lymphocytes & macro-phages present here, neutralize & engulf the

microorganisms, respectively.

MAJOR FUNCTIONS OF LYMPHATIC SYSTEM.

From Text Book Pg. 379.

EDEMA

DEFINITION “Whenever the tissue fluid accumulates rather than being drained into the blood by

the lymphatic system, tissue & body cavities become swollen. This condition is

known as “Edema”.

TYPES OF EDEMA

There are two types of Edema.

1. INTRACELLULAR

2. EXTRACELLULAR

1. INTRACELLULAR EDEMA

“Accumulation of excess of fluid within the cells causing cellular swelling is called

“Intra cellular Edema. It usually occurs after severe extracellular Edema.

2. EXTRACELLULAR EDEMA

“Excess fluid accumulation in extra cellular spaces is called Extracellular Edema. ”

It is the most commonly occurring form of Edema.



FACTORS CAUSING EDEMA

Any factor that increases the tissue fluid high enough than normal value can cause

excess tissue fluid volume causing edema. Some of these factor are as follows.

High blood pressure

Kidney failure

Hart failure & etc.

CAUSES OF EDEMA

Following are three main causes of Edema.

1. HYPOPROTEINEMIA (SEVERE DIETARY PROTEIN DEFICIENCY) When body is starving for Amino acids, it consumes its own blood proteins. This

reduces the osmotic potential of the blood causing tissue fluid to accumulate in body

tissues rather than being drawn back into capillaries, resulting in Edema.

2. LYMPHATIC OBSTRUCITON (COMMONEST CAUSE –FILARIASIS ) Another cause of edema is lymphatic obstruction, which results in more & more

protein collection in the local tissue fluid hence, the increased volume. Commonest

cause of lymphatic obstruction is FILARIASIS (infection by NEMOTODES) such

condition is also called as “Elephantiasis” (because of swollen legs).

3. INCREASED PERMEABILITY OF CAPILLARIES (CAUSES-BURNS &

ALLERGIC REACTIONS)

Sometimes the permeability of capillaries increase due to burns or allergic reactions,

so blood proteins & plasma come out of capillaries & enter the tissue fluid thus

causing Edema.

CLASSIFICATION ON THE BASIS OF MODE OF NUTRITION

Plants can be divided into two groups on the basis of their mode of nutrition.

1. AUTOTROPHIC

2. HETEROTROPHIC

1. AUTOTROPHIC NUTRITION

DEFINITION

“Autotrophic nutrition is the type of nutrition in which organic compounds are

manufactured from available inorganic raw material taking from surroundings”.

In autotrophic nutrition, the nutrients do not require to be pretreated or digested before

taking them into their cells.

TWO METHODS OF AUTOTROPHIC NUTRITION



On the basis of source of energy, autotrophic nutrition can be sub-divided into

following sub-types.

(I) Phototrophic nutrition

(II) Chemotrophic nutrition

I. PHOTOTROPHIC NUTRITION

DEFINITION “The type of autotrophic nutrition is which organic molecules are manufactured from

simple inorganic molecules by using light energy as a source is called Phototrophic

Nutrition”.

EXAMPLE

a. Green Plants

b. Photosynthetic Bacteria

(I-A) PHOTOTROPHIC NUTRITION IN GREEN PLANTS

Green plants are very prominent example of phototrophic nutrition. They prepare the

food by the process of photosynthesis.

RAW MATERIAL

The raw material needed by these organisms are

(1) CO2 AND H20

They provide carbon, hydrogen and oxygen for the synthesis of organic molecules.

(2) MINERALS The minerals like Nitrogen, Phosphorus and Sulphur and Magnesium are also

required.

(3) GREEN PIGMENTS

The green pigments i.e. Chlorophyll a, b, or others are also required to absorb the

energy from universal source of light.

(4) LIGHT

In the presence of sun light nutrients are used to synthesis the energy rich

compounded (CHO) This process is called “PHOTOSYNTHESIS”.

This process can be represented by equation as follows.

6CO2 + 12H2O -> C6H12O6 + 6O2 + 6H2O

(I-B) PHOTOTROPHIC NUTRITION IN PHOTOSYNTHETIC BACTERIA

Photosynthetic bacteria are unique because they are the only organisms which are

capable of synthesizing the carbohydrate food without chlorophyll “a”.



DIFFERENCES BETWEEN PHOTOSYNTHETIC BACTERIA AND GREEN

PLANTS

Photosynthesis in bacteria is different from green plants. Some differences are

Photosynthetic bacteria usually grow in sulphide spring where H2S is normally

present.

Hydrogen is provided by H2S instead of H2O.

Free oxygen is not released as a by product in bacterial photosynthesis.

The process takes place at low expenditure of energy.

TWO TYPES OF PHOTOSYNTHETIC BACTERIA

There are two types of photosynthetic bacteria.

(1) THOSE IN WHICH “S” IS RELEASED AS BY PRODUCT These bacteria use H2S as donor of hydrogen. Light splits hydrogen sulphide.

Hydrogen combines with CO2 to form H2O.

2H2S + CO2 -> (CH2O)n + H2O + 2S

EXAMPLES

Purple Sulphur Bacteria ® which use BACTERIO CHLOROPHIL & CARETENOID

as photosynthetic pigments.

(2) THOSE IN WHICH “S” IS NOT RELEASED AS BY PRODUCT These bacteria use H2S as Hydrogen donor where as sulphur is not the by product in

their case.

EXAMPLES PURPLE NON-SULPHUR BACTERIA

BROWN NON-SULPHUR BACTERIA

Both of these contain “BACTERIO CHLORPHYLL” as photosynthetic pigments.

(II) CHEMOTROPHIC NUTRITION

DEFINITION

“The mode of autotrophic nutrition in which organic molecules are manufactured

from simple inorganic molecules by using energy produced by the oxidation of certain

inorganic substances such as ammonia, nitrates, nitrites, ferrous ions, H2S and etc.

This type of nutrition is called CHEMOTROPHIC NUTRITION and process of

manufacturing food is called CHEMOSYNTHESIS.”

Mainly Bacteria are

AMMONIA USING BACTERIA

They derive their energy by oxidation of Ammonia.

NH4+ + O2 -> 2NO2 + 2H2O + 4H+ + energy



BACTERIA CONVERTING NITRITES TO NITRATES

2NO2 + O2 -> 2NO3- + energy

IMPORTANCE OF CHEMOSYNTHETIC BACTERIA

The chemosynthetic bacteria that act on nitrogen compounds do play an important

role in the maintenance of nitrogen balance in the life system.

2. HETEROTROPHIC NUTRITION IN PLANTS

DEFINITION

“Plants which are not capable of manufacturing their own organic molecules entirely

or partially depend for these organic molecular are called “HETEROTROPHIC

PLANTS”

CLASSIFICATION OF HETEROTROPHIC PLANTS

On the basis of type of organisms on which heterotrophic plants depend, they can be

classified into following two classes.

1. PARASITC PLANTS OR PARASITES

2. SAPROPHYTIC PLANTS OR SAPROPHYTES

1. PARASITES

DEFINITION

“Those heterotrophic plants which depend on living plants and animals for their

nutritional requirements are known as PARASITES.”

TYPES OF PARASITES

Parasitic plants can be divided into following types.

A. Obligate or total parasites.

B. Facultative or partial parasites.

1.A TOTAL PARASITES

DEFINITION

Those parasites which depend for their nutrition entirely on other living organisms

CLASSIFICATION OF TOTAL PARASITIC ANGIOSPERMS

Total or obligate parasitic angiosperms are broadly classified into

1. Total stem parasite

2. Total root parasite

1. TOTAL STEM PARASITES



DEFINITION

“Those parasitic plants which depend entirely on the stems of other plants are called

“Total stem Parasites”

EXPLANATION

These plants send HAUSTORIA (specialized structures for absorbing nutrients in

parasitic plants) inside the tissue of host. The xylem of parasite comes in contact with

xylem of host and phloem of parasite to phloem of host. Through xylem it sucks the

water and nutrients, through phloem prepared organic material. The host plant

eventually dies off due to exhaustion.

EXAMPLE CUSCUTA (AMER-BAIL)

2. TOTAL ROOT PARASITES

DEFINITION “Those parasitic plants which suck their nutritional requirements from the roots of

host are called “Total root parasites”.

EXAMPLES

OROBANCHE -> attacks the roots of the plants belonging to families Cruciferae and

Solanaceae

CISTANCHE -> Parasitizes on the roots of Calatropis.

STRIGA -> Found as parasite on the roots of sugar cane

(1.B)PARTIAL PARASITES

DEFINITION

“Those parasite plants which depend for their nutritional requirements partially on

other living organisms are called Falcultave or partial parasites.”

CLASSIFICATION OF PARTIAL PARASITIC ANGIOSPERMS

Partial parasitic angiosperms can be broadly classified into

1. PARTIAL STEM PARASITE

2. PARTIAL ROOT PARASITE

1. PARTIAL STEM PARASITES



DEFINITION Those partial parasites whose haustoria penetrate in the stem of the host and suck their

nutrition from vascular tissues of stem are called PARTIAL STEM PARASITE

EXPLANATION

LORANTHUS, is a partial stem parasite. It has thick green leaves, a woody stem and

elaborated haustorial system. It can manufacture some of its food with the help of

nutrients and water absorbed from host plants. The seeds get stuck upto the stem of

host plant and germinates sending its haustoria in the tissues of the host.

EXAMPLES

LORANTHUS -> found on shrubs, roseaceous tree, Bauhinia and mango

VISCUM -> produce haustorial branches for an internal suckling system.

CASSYTHA FILLIFORMIS -> found in tropics

2. PARTIAL ROOT PARASITES

EXAMPLE

The examples of this category are rare.

One important example is

SANDLE WOOD TREE

SAPROPHYTES

DEFINITION

“Those plants which depend for their nutrition on dead or rotten organic remains of

plants or animals are called as SAPROPHYTES”

or

“Plants which break up complex dead food material into simple compounds and use

them for their growth and development are called as SAPROPHYTES.”

TYPES OF SAPROPHYTES

Saprophytes can be divided into two types:

1. Total Saprophytes

2. Partial Saprophytes

1. TOTAL SAPROPHYTES

DEFINITION

“Those plants which depend entirely for their nutrition on dead organic matter are

called Total Saprophytes.



2. PARTIAL SAPROPHYTES

DEFINITION “Those plants which depend partially on dead organic matter are called Partial

Saprophytes.”

EXAMPLES OF SAPROPHYTES

There are some examples of Saprophytes among flowering plants.

1. Neothia (bird’s net or orchid)

2. Monotrapa (Indian Pipe)

In both of these cases, the roots of plant form a Mycorhizzal Association with fungal

mycelium to help in absorption process.

SPECIAL MODE OF NUTRITION

CARNIVOROUS OR INSECTIVOROUS PLANTS

DEFINITION “The plants which have as their prey, insects and small birds are called Carnivorous

plants. It is a special mode of nutrition in partially autotrophic and partially

heterotrophic plants.”

EXPLANATION

Partially autotrophic and partially heterotrophic plants are carnivorous, which possess

the green pigments and can manufacture CHO but are not capable of synthesizing

nitrogenous compounds and proteins. For their nitrogen requirement, carnivorous

plants have to depend on insects, which they catch and digest by specific devices

developed in them. J.D. Hooker suggested that the digestion of carnivorous plants is

like that of animals.

COMMON AREAS WHERE THESE PLANTS GROW

These plants commonly grow in areas where nitrogen is deficient due to unfavourable

atmosphere for nitrifying bacteria but favourable atmosphere for denitrifying bacteria.

SOME COMMON EXAMPLES

1. PITCHER PLANT In Pitcher plant leaf is modified into pitcher like structure which is insect trapping

organ.

EXAMPLES

Common examples are :

Nepenthes

Sarracenia



Cephalotus

Neliamphora

Darling tonia

2. DORSERA INTERMEDIA OR SUNDEW

This plant has half a dozen prostrate radiating leaves, which bear hair like tentacles

each with gland at its tip. The insects attracted by plant odour are digested.

3. DIONAEA MUSCIPULA OR VENOUS FLY TRAP Most well known of all carnivorous plants. It has a resette of prostrate radiating leaves

with inflorescence in the centre. The petiole of leaf is winged and lamina has two

halves, with mid-rib in the centre. Each half has 12-20 teeth. In the centre of dorsal

surface of lamina are numerous secretory glands, three hairs projecting out, which are

sensitive to touch.

4.ALDROVANDA (WATER FLY TRAP)

It is a root less aquatic plant with floating stem. It has ressettes of modified leaves,

which have two lobed mobile lamina having teeth at the margin and sensitive jointed

hairs and glands on the surface.

5. UTRICULARIA OR BLADDER WORT

It is a root less plant having branched slender stem. Leaves are also much divided and

some leaflets are modified into bladder like traps of about 1/16 to 1/8 inches in

diameter.

MAIN CHARACTERS

NATURE

Annelida are triploblastic, symmetrical, coelomata and segmented metozoa.

HABIT AND HABITAT

Annelida are mostly aquatic, marine or fresh water, burrowing or living in tubes, some

free living forms.

EXTERNAL FEATURES

The most important feature of annelida is their metameric segmentation. (External

segmentation)

Segmentation is indicated externally by circular constrictions or grooves on the body

wall.

Outer covering of the body is cuticle secreted by the underlying epidermis.

Appendages, when present are un jointed.



Locomotory organs are segmentally arranged, paired setae or chaetae.

INTERNAL FEATURES

Body wall is contractile, consists of an outer epidermis, circular and longitudinal

muscles.

The gut, longitudinal blood vessels and the nerve cord extend throughout the body

length, whereas other structures are repeated in each segment.

Important character of annelida is the development of series of coelomic

compartments in their body between the gut and the body wall.

The Coelom is a cavity, which develop within the mesoderm and is lined by

mesodermal cells.

Segmented musculature plays an important part in locomotion of Annelids.

SYSTEMS OF BODY

Alimentary canal is tube like extending straight from mouth to anus.

Respiration through general body surface, by gills in some forms.

Blood vascular system is closed type.

Blood is red due to haemoglobin.

Excretory organs are Nephridia usually one pair in each segment.

Nervous system consists of dorsal brain and longitudinal ventral nerve cord.

Sexes may be united or separate.

Development is direct when sexes are united and indirect when sexes are separate.

EXAMPLES

Nereis, Earthworm and Leeches etc.

CLASSIFICATION OF PHYLUM ANNELIDA

Phylum Annelida is divided into four classes:

1. Polychaeta

2. Oligochaeta

3. Hirudinea

4. Archiannelida

1.POLYCHAETA

LOCOMOTORY ORGANS

The Polychaetes possess paired parapodia functioning as locomotry appendages, are

present only in the class Polychaeta.

PROSTOMIUM Usually there is a distinct head or Prostomium bearing sensory and feeding

appendages.



MODE OF LIFE

The Polychaetes may be carnivorous, scavengers, or filter feeders.

REPRODUCTION

The sexes are separate and fertilization of eggs takes place outside body. Their free

swimming larva is called Trochophore.

RESPIRATION The respiration takes place through the body surface in many but in some gills may be

present as respiratory organs.

EXAMPLES

Some well-known examples of marine polychaetes are Nereis, Arenicola and Sabella.

Nereis lives beneath stones and in crakes of rocks.

2.CLASS OLIGOCHAETA

LOCOMOTORY ORGANS The Oligochaetes possess fewer numbers of Setae as compared to the Polychaetes.

The setae help the earth worms in crawling.

SENSE ORGANS There anterior end lacks eyes, or sensory appendages.

CLITELLUM At sexual maturity, all of the oligochaetes develop in several segment, glandular

epithelium, called clitellum.

MODE OF LIFE

Oligochaetes live either in fresh water or on land.

There is no free swimming larval stage in their development

Majority of oligochaetes are scavengers, feeding on decomposing organic matter.

Some fresh water species feed on algae.

Burrowers like earth worm ingest a large quantity of soil, digest the organic matter

and the living fauna.

RESPIRATION

Respiration takes place through their general body surface. Some aquatic species

possess anal gills.



ECONOMIC IMPORTANCE Earthworms increase the fertility of soil by physically over turning it. They ingest the

soil, break it down and deposit it in the form of casts. The over turned soil is relatively

in proportions of total nitrogen, organic carbon, calcium, magnesium and phosphorus.

3.CLASS HIRUDINEA

BODY SEGMENTS Unlike polychaetes and oligochaetes, the number of body segment in leeches is fixed

at 34.

SUCKERS The anterior and posterior body segments are fused to form suckers.

LOCOMOTION Leeches either swim or crawl.

RESPIRATION

Respiration generally takes place through the body surface. Leaf like gills may be

present.

PARASITIC NATURE

Most leeches feed by sucking blood of aquatic invertebrates and vertebrates.

4.ARCHIANNELIDA

It is a small group of marine worms.

They are not segmented externally and don’t have bristles.

They live in the sea and show annelid characteristics to a minor extent.

Their development is also characterized by Trochophore Larva.

EXAMPLES Nerilla

Dinophilus

MAIN CHARACTERS

HABIT AND HABITAT

Nematoda have a very wide distribution and they seem to have mastered almost every

habitat.

Free living nematodes are found in the sea, fresh water or in the soil in all kinds of

environment.

There are also many Parasitic nematodes found in all groups of Plants and animals.



The Saprophagous species live in decomposing plant and animal bodies and in rotting

fruits.

NATURE

They have a bilaterally symmetrical, cylindrical body, glistening smooth surface.

They are triploblastic.

EXTERNAL FEATURES

They show no trace of segmentation.

Most of the free living nematodes are less then a millimeter length.

Some of the parasitic species attain a length of several meters e.g. Guinea worm

(Dracunculus medinensis).

They are usually long, round, tapered at both ends showing very little morphological

diversity from species to species.

The mouth of nematodes is modified for various modes of feeding such as cutting,

tearing, piercing and sucking fluids from the host.

Body is covered by cuticle, which moults only during the period of growth.

INTERNAL FEATURES

The organs are packed in parenchyma when young, but later on it disappears in adult.

So that organs lie in a fluid filled cavity. This cavity is termed as PSEUDOCOEL and

it has not peritoneum.

Muscles are only longitudinal.

Excretory system has no flame cells.

Alimentary canal is straight with ectodermal fore and hind gut and an endodermal mid

gut.

REPRODUCTION

Sexes are generally separate.

Gonades are tubular and continues with their ducts.

Female organs are usually paired and open by vulva.

Male organs are single and open into a cloaca.

The life cycle of Parasitic species involves one, two or more hosts

EXAMPLES

Ascaris (Round worms), Hookworms and Thread worms etc.

GENERAL CHARACTERS

1. NOTOCHORD



It is an elastic, solid, skeletal rod lying below the nerve cord and above the alimentary

canal.

It serves as a primitive internal skeleton and acts as a rigid axis.

It may persist throughout life or it may be replaced partially or completely by a

backbone or vertebral column.

2. DORSAL HOLLOW NERVOUS SYSTEM

There is a dorsal, hollow, fluid filled nerve cord.

It is formed by enfolding of a mid-dorsal strip of ectoderm and it generally sinks

below the surface.

It lies above the notochord and outside the coelom.

It persists throughout life in most chordates, but in a few it degenerates before

maturity.

3. GILL CLEFTS

These are paired openings leading from the Pharynx to the exterior.

Such gill clefts appear during the development of every chordate, but in many aquatic

forms they are lined with vascular lemallae, which forms gills for respiration.

In terrestrial chordates, which never breath by gills, gill clefts are present during early

development but later on, they disappear.

4. PHA-RYNGEAL POUCHES

All the chordates have paired pharyngeal pouches at some stage of their life cycle.

These extend from laterally from the anterior part of the digestive tract towards the

body wall.

OTHER FEATURES

Chordates are triploblastic.

They are bilaterally symmetrical.

True coelom is found.

They are found in almost all the habitats of the World.

CLASSIFICATION OF PHYLUM CHORDATA

The Phylum Chordata is divided into two groups which are:

1. Acraniata (Protochordata)

2. Craniata (Vertebrata)

1. GROUP ACRANIATA (PROTOCHORDATA)

They are first or simple Chordates.

Brain box (Cranium) is absent and hence brain is not prominent.

Notochord does not transform into vertebral column.



This group is further divided into two sub-phyla, which are as follows:

a) Sub-Phylum Urochordata (Notochord in tail)

b) Sub-Phylum Cephalochordata (Notochord head to tail)

A) SUB-PHYLUM UROCHORDATA (NOTOCHORD IN TAIL)

They are also known as “Tunicates” because their body is enclosed in a sac called

“Tunic.”

All members are marine and sessile.

Body possesses two openings, an incurrent or buccal siphon and an excurrent or Atrial

siphon, through these openings exchange of gases and food or waste material take

place.

As a result of “Retrogressive metamorphosis” the larva loses its tail and most of

chordate characters and converts into an adult.

E.g: Ascidia, Herdmania etc.

B) SUB-PHYLUM CEPHALOCHORDATA (NOTOCHORD FROM HEAD TO

TAIL)

This is a small group of marine animals, body with pointed ends.

Usually live buried in sand, in shallow water with anterior end protruded out.

They show all typical chordate characters (hollow dorsal nerve chord, pharyngeal gill

slits and notochord).

Only two genera are present around the world.

E.g: Branchiostoma (Amphioxus) etc

2. GROUP CRANIATA (VERTEBRATA)

In these chordates brain is protected inside a skeletal brain box called “CRANIUM.”

Also known as “Vertebrates” because notochord is replaced by a vertebral column.

This group is sub-divided into two sub-phyla, which are as follows:

a) Sub-Phylum Agnatha (Mouth without Jaws)

b) Sub-Phylum Gnathostomata (Mouth with Jaws)

A) SUB-PHYLUM AGNATHA (MOUTH WITHOUT JAWS)

This is a small group of marine vertebrates also known as “Cyclostomes.”

Superficially they resemble the fish but lack the jaw so they are often known as

“Jawless Fishes.”

They have rounded suctorial mouth with many rings of teeth.

Paired fins and scales on body.

Usually parasitic in nature.

E.g: Hag Fish, Lamprey etc.

B) SUB-PHYLUM GNATHOSTOMATA (MOUTH WITH JAWS)

It is a large group of vertebrates with both upper and lower jaw.

Teeth may be present or absent.

Gnathostomata are divided into two super classes, which are as follows:

i) Pisces (Fishes)

ii) Tetrapoda



I) SUPER CLASS PISCES (FISHES)

This is the largest group of chordates, which includes half of the chordate (25,000

species).

Study of fishes is called “Ichthyology.”

Body is streamlined with paired fins and covered over by dermal scales.

Super class Pisces is divided into two classes, which are:

i-a) Chondrichthyes (Cartilage Fishes)

i-b) Osteiochthyes (Bony Fishes)

I-A) CLASS CHONDRICHTHYES (CARTILAGE FISHES)

Alternate name is “Class Elasmobranchi.”

Usually includes marine fishes with endoskeleton of cartilage (soft bone).

Skin contains sharp tiny enamel coated denticles called “Placoid Scales,” which form

exoskeleton.

Mouth is ventral in position and tail fin is “Heterocercal.”

Five exposed gill slits, which are not covered over by a gill cover.

Common examples are Skates, Sharks, Rays and Scoliodon (Dog Fish)- a small Shark

etc.

I-B) CLASS OSTEIOCHTHYES (BONY FISHES)

Alternate name is “Teleostom,” actually the largest class of chordates.

Includes marine and fresh water fishes.

Mouth is present at anterior tip.

Endoskeleton in these fishes is made up of hard bone while exoskeleton is made up of

thin bony plates, which are known as “Cycloid” or “Ctenoid scales.”

Gills are covered over on each side by a gill cover called “Operculum.”

An air bladder is present which acts as a hydrostatic organ.

Tail fin is usually “Homocercal or Diphycercal.”

Common e.g are Eel, Sea-Horse, Flying Fish, Globe Fish etc

LUNG FISHES

Zoogeographically important fishes, belonging to group “Dipnoi, included in Class

Osteiochthyes.

Only three living genera.

They respire by gills and by lungs during drought period (Lungs-Modified air

bladder).

Limited distribution in South America, Africa and Australia.

E.g: Protopterus (African Lung Fish)

II) SUPER CLASS TETRAPODA

It includes following classes:

a) Class Amphibia



b) Class Reptilia

c) Class Aves

d) Class Mammalia

A) CLASS AMPHIBIA

This class includes the animals that came out of the water and established a successful

life on land.

They took advantages of the improved possibilities by remaining close to water, by

keeping a soft and moist skin, by developing lungs and by evolving a bony skeleton

with a strong vertebral column and four legs.

They cope with seasonal changes by burrowing during extreme cold and save water

by sealing themselves in a mucous envelop on dry land.

The bony endoskeleton is the main body support.

The notochord is absorbed during development

Breathing is mostly by means of skin and also lung, and also by lining of buccal

cavity.

In larva the breathing is mostly by means of external or internal gills.

The circulatory system shows a three chambered heart, with two atria and one

ventricle.

The amphibians are “Cold Blooded” (Poikilothermic) that is having internal

temperature that very with the environment.

Eggs and sperms are laid in water and fertilization is external.

E.g: Frog and Toads, Salamanders, Newts, Mud puppies etc.

B) CLASS REPTILIA

GENERAL CHARCTERS

The earliest reptiles evolved from the amphibians.

HABIT AND HABITAT Reptiles are generally well adapted to life on land, in semi-dry, completely dry and

even desert habitat.

NATURE

All reptiles lay their eggs on land.

They are cold-blooded animals and are less active during low temperature.

STRUCTURAL FEATURES

They possess dry skin covered with epidermal scales.

In some lizards and crocodiles, small bony plates develop below the epidermal scales.

The skeleton is built on the same plane as that of amphibians, but is much stronger to

support their body weight.

Respiration takes place exclusively through lungs.



Heart is three chambered, two auricles and one incompletely divided ventricle. (In

Crocodiles, the ventricle is completely divided into two chambers.)

The excretion takes place through kidneys. The reptiles secrete much of their waste

products in form of non-toxic “Uric-Acid.”

REPRODUCTION

In most reptiles fertilization is internal.

Eggs are provided with a shell and are laid on land.

The early development of embryo takes place on the large quantities of yolk and

albumin present in the egg.

Due to the presence of a protective membrane called “AMNION” in the egg, reptiles

are included in the “Amniota Group” of Vertebrates.

EXAMPLE

Alligators, Crocodile, Snake, Turtle and Gecko etc.

C) CLASS AVES (BIRDS)

EVOLUTION

Aves have evolved from reptiles.

As they acquired the capability of true flight they were able to exploit the aerial

environment and became the largest class of terrestrial vertebrates.

CHARACTERS OF CLASS AVES

HABIT AND HABITAT

The birds live from pole to pole in all type of ecological zones. They all breed

on land.

FLIGHT AND ADAPTATION

Feathers differentiate birds from all other vertebrates.

Feathers originated as extraordinary development of Reptilian scales.

Instead of growing all over the body and spreading evenly, the feathers grow in

definite tracts.

The feathers play an important role in the thermoregulation of birds. They trap air,

which is a bad conductor of heat and so prevent loss of body heat.

To fly efficiently the birds have reduced their body weight in a variety of ways.

Many bones become hollow, thin and light.

Synsacrum and pygostyle are formed by the fusion of vertebrae and give strength to

skeleton.

Birds possess strong muscles to control the use of wing in flight.



ADAPTATION FOR COMMUNICATION

They possess large eyes with well-developed sight.

The birds communicate with members of their species with sound signals for which

the sense of hearing is well developed.

STRUCTURAL FEATURES

The great mobility of neck is helpful in feeding, nest building, preening and defence.

There are developed a number of types of bills according to their feeding habits.

The digestive system of birds is compact and can accommodate large quantity of food.

The food is stored for a short period in the crop.

“Gizzard” possess thick muscular wall with horny lining, small stones swallowed by

birds are passed on the gizzard for grinding the food.

The “Syrinx” or sound-producing organ is found in no other vertebrate except the

birds. It is located at the junction between the trachea and the paired bronchi.

The lungs of birds are small, solid, spongy and slightly distensible. They are in

contact with a number of air sacs.

MIGRATION IN BIRDS

A large number of species of birds exhibit a deep-rooted phenomenon of migration,

during which they travel long distances from their summer breeding homes towards

areas of warm climate.

SUB-CLASSES OF AVES

There are two main sub-classes of aves, which are:

i) Sub-Class Ratitae (Flightless Birds)

ii) Sub-Class Carinatae (Free-Flying Birds)

I) SUB CLASS RATITAE (FLIGHTLESS BIRDS)

This sub-class includes modern big sized flight less birds.

They comparatively have heavy weight and their wings are either vestigial or

rudimentary.

They have a flat sternum without keel.

Their flight muscles are poorly developed.

The distribution of these birds is restricted to few areas of the World.

E.g: Ostrich, Rhea, Emu, Cassowary, Kiwi and Penguin.

II) SUB-CLASS CARINATAE (FREE FLYING BIRDS)

In this sub-class modern flying birds are included.

They are usually small, light weight birds with highly developed wings and feathers

with interlocking system.

They possess sternum with a crest like keel to accommodate the hightly developed

pectoral flight muscles.

The flying birds are distributed all around the World.



E.g: Sparrow, Pigeons, Myna, Bulbul, Hoopoes, Crow, Doves, Parrots, Fowls,

Cuckoo and Ducks etc.

D) CLASS MAMMALIA

GENERAL CHARACTERS

Early mammals are originated from reptiles. The distinctive characteristic of

mammals are at the highest grade of development in animal kingdom.

HABIT AND HABITAT

Mostly terrestrial, a few aquatic.

NATURE

They are warm-blooded animals.

They can maintain a fairly high body temperature and so can successfully survive in

colder areas of the world.

TEMPERATURE REGULATION

Heat is generated by high metabolic rate of their body and is lost by increasing blood

circulation in the skin and evaporation of sweat.

The mammalian body temperature is maintained at 35?C-40?C.

APPARENT FEATURE

All mammals possess hair on skin.

Sweat glands and sebaccous glands are present on skin.

Mammary glands secrete milk in females.

External ears (Pinna) are present.

Teeth are heterodont i.e. not uniform. The different types of teeth are: Incisors,

Canine, Premolars, Molars.

SKELETAL SYSTEM

Skull with two occipital condyles is present.

Lower jaw is composed of single bone on each side.

Vertebrae are “Gastrocentrous,” composed of three pieces i.e. the centrum and two

epiphyses.

Digits of fore and hind limbs are usually five.

Cervical (Neck) vertebrae are seven.

INTERNAL FEATURES

A thick muscular septum “Diaphram” is present between abdomen and thoracic

cavity.

Heart is four-chambered.

R.B.Cs are non-nucleated.

Brain with four optic lobes.

Kidney is metanephrous.



The stomach is simple sac but rarely complicated.

REPRODUCTION

Mammals give birth to young ones (Viviparous), which are nourished by parents.

Except Prototherians that lay eggs.

Fertilization is internal.

Development of eggs occurs in the uterus of female, where the developing embryo

develops relationship with mother (Placenta).

After the birth of the child, the mother nourished her young ones.

CLASSIFICATION OF CLASS MAMMALIA

Mammals are divided into three sub-class:

1. SUB-CLASS PROTOTHERIA

Includes the egg laying mammals. For example Duck billed, Echidna (Spiny anteater).

2. SUB-CLASS METATHERIA

Includes the pouched mammals, also known as “Marsupial mammals.” For example

Kangaroo, Koala Bear and Opossums etc.

3. SUB-CLASS EUTHERIA

Includes the placental mammals. For example Monkey, Cow, Elephant, Cat, Dog, Bat,

Whale and Human being etc.

Chapter-4

CELL

It is the basic structural and functional unit of life, which is able to carry out all the

life processes.

CELL THEORY

The cell theory was collectively proposed by “Schleiden(1838), Schawnn(1839) and

Virchow (1858).

IMPORTANT POSTULATES

The fundamental points of the cell theory are:

(a) The cell is the structural and functional unit of all living organism.

(b) All organisms are composed of one or more cells.

(c) New cells can arise only by division of pre-existing cells.



Thus cell theory established the concept that the function of an organism is the result

of activities and interaction of the cell units.

MICROSCOPE

DEFINITION

An instrument with the help of which we see small, tiny and minute objects which

can’t be observe by naked human eye.

TYPES OF MICROSCOPE

There are three main types of microscope.

1. LIGHT MICRO SCOPE

In this microscope visible light is used as source of illumination.

2. X-RAY MICROSCOPE

X-Rays are used as source of illumination.

3. ELECTRON MICROSCOPE Electron beam is used as source of illumination.

There are further two sub-types of electron microscope which are:

(A)TRANSMISSION ELECTRON MICROSCOPE

In this type resultant image is obtained on a fluorescent screen or photographic film.

(B)SCANNING ELECTRON MICROSCOPE In this type resultant image is obtained on a television screen.

MAGNIFICATION OF MICROSCOPE

Ability of microscope to increase the shape and size of the objects image. It can be

calculated by multiplying the power of its eye pieces with its magnifying power of its

objective.

RESOLUTION OF MICROSCOPE

The capacity of microscope to separate adjacent forms or object. Also known as

“Minimum Resolved Distance”.

CONTRAST

It is important to distinguishing one part of cell from another.

(Difference between light and electron microscope – From Text page #57)

Prokaryotes and eukaryotes – From Text page #58)

CELL MEMBRANE

Each cell is covered by an asymmetrical, porous, thin, semi permeable sheet called

cell membrane or plasmalemma.

CHARACTERISTICS OF CELL MEMBRANE



Living part of the cell, consist of lipid + protein.

1.5 micron in thickness.

Consist of two layers of lipid.

Lipid of plasma membrane are,

1. Phospho-lipids

2. Glycolipids

3. Sterol

4. Cholesterol.

STRUCTURE OF CELL MEMBRANE

Cell membrane made up of phospho-lipids bilayer and each layer consists of ,

1. Head (hydrophilic end)

2. Tail (hydrophobic end)

1. HEAD (HYDROPHILIC/POLAR END) Present towards the surface and formed of phosphates.

2. TAIL (HYDROPHOBIC/NON-POLAR END)

Present towards the center and formed of fatty acids.

The non-polar ends of phospho lipids face each other, whereas their polar ends are in

association with protein or carbohydrates between every two phospo lipids molecule

lies a molecule of “Cholesterol”.

FLUID MOSAIC MODEL

INTRODUCTION The fluid mosaic, bilayer model was proposed by “Singer and Nicolson (1972).

POSTULATES OF FLUID MOSAIC MODEL

Important postulates of this model are,

(a) The cell membrane consists of lipid bilayer, in which a variety of proteins are

present.

(b) These proteins float in the fluid matrix of lipid (as ice bergs in the sea)

(FIGURE 4.4 Page #61)

ARRANGEMENT OF PROTEINS

According to the fluid mosaic model proteins are:

1. INTRINSIC/INTEGRAL PROTEINS

These proteins peneterate the membrane surface and enter the lipid layers (partially or

wholly)

2. EXTRINSIC/PERIPHERAL PROTEINS

These are located adjacent to outer and inner surface of membrane and float like ice-

berg in the sea.



ARRANGEMENT OF LIPIDS The non-polar end face each other while their polar ends are towards the surface.

SIGNIFICANCE OF MODEL

Cell membrane is flexible.

Can change shape (because the protein and lipid of the membrane can move).

FUNCTION OF MEMBRANE PROTEIN

Certain proteins themselves act as enzymes.

Some protein act as carrier for active transport.

Provide elasticity to membrane.

Pores are lined by the proteins.

FUNCTION OF LIPIDS PRESENT IN MEMBRANE

The lipids give rigidity to cell membrane.

They lower the surface tension.

FUNCTIONS OF CELL MEMBRANE

It performs the two main function.

Protection of Protoplasm.

Regulation of material (In and Out of cell) through its permeabality.

PERMEABILITY OF MEMBRANE

The permeability of membrane is regulated by two processes.

(1) Passive Transport (Osmosis and Diffusion)

(2) Active Transport (Endocytosis, Exocytosis)

1. PASSIVE TRANSPORT Such type of molecules transport which does not require energy. It is further divided

into,

DIFFUSION

Spreading and free movement of molecules (or ions) from the region of higher

concentration to the region of lower concentration (till equilibrium state)

SIGNIFICANCE

Movement of oxygen and digested food (glucose, amino acids, fatty acids) into the

cell.

Movement of excretory waste out of cell.

OSMOSIS

Diffusion of water by semipermeable membrane or the movement of solvent

molecules from higher to lower concentration across semi permeable membrane.



SIGNIFICANCE

Liquids, primarily water molecules enter and leave the cell by Osmosis.

It helps to maintain a balance (osmotic pressure) in and out of cell.

2. ACTIVE TRANSPORT

Such type of molecule transport which require energy. Or Movement of molecules

against the concentration by the expenditure of energy through a carrier (i.e.

movement of molecules from the region of lower concentration to higher

concentration by protein using ATP as energy.

SIGNIFICANCE

Absorption of excess food (glucose), ions (K+ and Na+) takes place by Active

transport.

CONDITIONS

It is unidirectional.

ATP provides energy.

Protein act as carrier.

Active transport is further subdivided into,

(1) Phagocytosis and Pinocytosis (Endocytosis).

(2) Exocytosis.

PHAGOCYTOSIS

Process of picking and ingestion of large solid particle by plasma membrane (which

can not enter by diffusion, osmosis or active transport).

SIGNIFICANCE

Ingestion of solid food particles.

WBCs pick foreign particles (certain bacteria)

PINOCYTOSIS Process of fluid intake, for absorbing fluid by forming pinocytic vesicle (the fluid

which cannot be absorbed by osmosis, enters through it)

SIGNIFICANCE

Helps in absorption of harmones, lipids etc.

CELL WALL

The cell wall is the outer most covering of a plant cell. It is composed of cellulose (a

carbohydrate) and some other chemical substances.

This hard covering gives form, firmness and strength to the plant cell.

In a young cell it is thin and delicate but in a mature cell it becomes thick due to the

deposition of various chemical substances on its inner surface.

There are three layer of cell wall.



1. MIDDLE (LAMELLA)

First formed cell plate.

Cementing layer between two daughter cells.

Composed of Ca++ and Mg++ pectate.

Cells are separated when this layer is dissolved.

2. PRIMARY WALL

First product of cell synthesized by protoplast.

In young cells it is thin and elastic while it becomes thick and rigid on maturity.

Made up of Hemicellulose (50%), cellulose (25%) and pectate substances.

3. SECONDARY WALL

Composed of cellulose.

Present inside the primary wall.

Can be modified through the deposition of lignin and other substances.

NUCLEUS

It control all the activities of the cell and was discovered by Robert Brown in 1831.

It consist of the following parts,

(1) Nuclear Membrane.

(2) Nucleoplasm or Karyoplasm.

(3) Nucleolus.

(4) Chromatin Network.

1. NUCLEAR MEMBRANE

The nucleus is bounded by a double layered membrane which bears pores and is

known as “Nuclear Membrane”

2. NUCLEOPLASM

Inside the nuclear membrane is a structure less fluid called “Nucleoplasm” and highly

rich with proteins.

3. NUCLEOLUS

It is a patch work of granules rich in R.N.A formed in the nucleus. They may be more

than one in a single nucleus. It contains mRNA formed from DNA, later mRNA

comes out of nucleus to control protein formation.

4. CHROMATIN NETWORK

There is a network of threads dispersed in the karyoplasm called (Chromatin network)

Each individual thread is called (Chromosomes).



These are made up of DNA and are carrier of genes.

NOTE:(Types of Chromosomes from Book Page# 66)

MEMBRANE BOUND ORGANELLES

(1) ENDOPLASMIC RETUCULUM

It is a complex series of tubules in the cytoplasm. Endoplasmic reticulum are of two

types,

(1) Agranular or Smooth EPR.

(2) Granular or Rough EPR.

SMOOTH EPR

It has no attached ribosome’s.

Function is to synthesis lipid.

ROUGH EPR

It has ribosome’s attached to its outer surface.

Synthesize protein and also transport material within the cell.

(2) MITOCHONDRIA

An oval body bounded by a double membrane. The inner membrane is folded to form

shelves/incomplete partitions. Which are known as “Crista”, here oxidative enzyme

are present. They are sites for aerobic cellular respiration and the energy is produced.

Therefore also known as “Power house of cell”

(3) GOLGI APPARATUS(DICTYOSOMES)

These are thin, plate like structures and are usually located near the nucleus. These are

the site of formation of lysosomes and also conjugate protein, modify structure of

substances, synthesized by EPR to form lysosomes and secretary vesides. Golgi

bodies of plants and lower animals (mostly invertebrates) are known as

“Dictyosomes”.

(4) LYSOSOMES

They are large, some what irregular structure formed in the cytoplasm formed by

golgi-bodies. They contain hydrolytic enzymes which destroys foreign particles. They

are also known as “Suicide Sacs” because after secreting the enzymes they digese

their own proteins (Autophagy).

NOTE:(Lysosomal Storage Diseases From Text Page # 71)

(5) PLASTIDS



They are specialized organelles of plant cell that contain pigment or they synthesize

reserve substances.

They are of three kinds,

(A) LEUKOPLAST leuco = white

Leukoplast are colourless and store nutrient material.

(B)CHLOROPLAST

Chloroplast are green having chlorophyll that performs photosynthesis.

(C) CHROMOPLAST Chromo = Colour

Chromoplast contain different coloured (red, yellow, orange or other than green)

pigments. They are found in the cells of different coloured flowers and fruits.

(6) MICRO BODIES

It includes peroxisome and glyoxysome.

(A) PEROXISOME

These are the single membrane bounded microbodies contain enzymes for transferring

hydrogen atom to oxygen i.e. forming hydrogen peroxide.

Hydrogen peroxide is very toxic to the cell therefore it is immediately break down to

water by enzyme catalyst.

These microbodies help in detoxyfication of alcohal and mostly present in liver cells.

(B) GLYOXYSOME

It is a single layered membrane bound structure containing enzymes which metabolize

some molecules in photosynthesis and respiration.

They also cause oxidation of fatty acids.

CYTOSKELETON

Cytoskeleton means skeleton of the cell, which is mostly composed of microtubules,

microfilaments and intermediate filaments.

(A) MICRO TUBULES

Microtubules are hollow cylinders with an outerdiameter of 25nm.

They are made up of a special type of globular protein tubulin.

In single microtubule consist of hundredth of thousands of tubulin sub units, which

are usually arranged in 13 columns called Protofilaments.

Microtubules are arranged in assemble and disassemble manner.

In animal cells and lower plants they also form centriole, cilia and flagella.

(B) MICROFILAMENTS

Microfilaments are solid structures, thread like with a diameter of 7nm.

They are also composed of globular proteins.



Each microfilament consist of two actin (Protein) chains that inter wing in a helical

fashion.

(C) INTERMEDIATE FILAMENTS

They are intermediate in size having a diameter of 8nm to 11nm.

They are rope like polymers of Fibrous protein.

In skin and hair these filaments are made up of protein keratin.

They provide mechanical strength to the cell and support the nuclear envelope.

NON MEMBRANE BOUND CYTOPLASMIC ORGENELLE

(1)RIBOSOMES

These are small structures concerned with protein synthesis in all type of the cells i.e.

Prokaryotic as well as Eukaryote.

They are freely dispersed in cytoplasm of Prokaryotic cell but in Eukaryotic cells they

may be free or attached with endoplasmic reticulum.

More than 50 type of proteins are present in ribosome structure and they contain high

quantity of RNA.

Under the direction of Nucleus ribosome produce the protein made it by the cell.

Each Ribosome consist of two unequal parts.

These are the smallest and most vital cellular components, manufactured in the

nucleolus.

(2) CENTRIOLE

They are only present in animal cells and certain lower plants.

Mostly near the nucleus.

Each centriole consist of two cylinders lying perpendicular to one another.

Each cylinder consist of nine parallel triplets of hollow cylindrical microtubules.

During the cell division they replicate and move towards opposite poles of the cell.

In mitosis and meiosis they form thread like fibers which rediate from each centriole

are known as mitotic apparatus.

(3)VACUOLES

These are non-protoplasmic fluid filled cavities in the cytoplasm.

Their membrane is known as Tonoplast.

They are more prominent in mature cells.

In plant cells vacuoles are filled with cell sap and act as store, house.

They also play an important role in plant defence.

In animal cells vacuole contain hydrolytic enzymes (i.e. lysosomes)

Chapter -5

BASIS OF CLASSIFICATION OF LIVING ORGANISMS



The living organisms are classified on the basis of Homology, comparative

Biochemistry cytology and Genetics.

(a)Homology

(b)Cytology.

(c)Bio-chemistry.

(d)Genetics

(A)HOMOLOGY

The organisms placed in a particular group, all have many fundamental similarities in

their structure.

EXAMPLE

The flipper, wing and arm are, all build on the same pattern but during the course of

evolution, each has been modified from its basic pattern to serve a particular and

usually highly specialized function, due to its adaptation different to environment or

habitate. (Structures that are similar because of their common origin but may differ

functionally is known as Homologus)

(B)BIOCHEMISTRY

It is particularly useful, when we classify organism like bacteria, which may all look

alike and have an identical cellular structure with the help of chromatography and

electrophoresis we can compare the amino acid sequence in the protein of different

organisms or the order of bases in their DNA.

(C)CYTOLOGY

Microscopic observations of cell structure are also used to make a fundamental split in

the classification of living things. They can be useful at the level of generic and

species level. This sort of technique can show delicate difference between species or

sub-species, which are identical in many other respects. Specie → Genus → Family

→ Order → Class → Division → Kingdom

(D)GENETICS

All the morphological, Bio-chemical properties and cytological aspects of an

individual, or of a species depend on its genetic constitution. Hence the final tool

helping in classifying an organism is Genetics.

TAXONOMIC HIERARCHY

The basic unit of the biological classification is specie. Closely related species are

grouped-together into Genera. Genera are grouped into Families, families into order,

orders into classes, classes into phyla and phyla or divisions into kingdoms. Each

grouping of organisms with in the hierarchy is called taxon and each taxon has a rank

and a name. For example class “mammalia” or Genus “Homo”. This ascending series

of successively larger, more inclusive groups make up the “Taxonomic Hierarchy”.

CHANGES PROPOSED BY MARGUILES AND SCHWARTZ IN THE FIVE-



KINGDOM SYSTEM

Marguiles and schwartz were American Biologist, put forward a modification of

Robert Whittaker’s scheme. According to this modification.

The multicellular alga should be removed from the plant kingdom and placed along

with all unicellular organisms, in a new kingdom called “PROTOCTIST” which

would replace Whittaker’s Protista kingdom.

This modification made the plant kingdom a more natural group.

Due to this modification the kingdom Protoctista became a kingdom that contains all

those organisms, which cannot be fitted into any of the other kingdom.

VIRUS

Virus are very minute non cellular bodies considered between living and non-living

organisms.

DISCOVERY OF VIRUS

The word virus is derived from a Latin word meaning “Poison”. A Russian Biologist

Iwanosky in 1892 discovered Virus.

CHARACTERISTICS OF VIRUS

1. Viruses are non-cellular parasitic entities (obligate parasite)

2. Viruses cannot live and reproduce outside the living cells because they lack the

machinery to do so by themselves.

3. The size of the viruses in range 20nm-250nm.

4. Viruses are either virulent destroying the cell in which they occur. While temperate

Viruses become integrated into their host genome and remain stable for long period of

time.

STRUCTURE OF VIRUS

1. The viruses may be small sphere like or golf balls, like rod shape tadpole and

polyhedral.

2. They mainly consist of viral genome, capsids, envelopes and tail Fibers.

(A)GENOME

Viral genomes may consist of a single or several molecules of DNA or RNA.

(B)PROTEIN CAPSID (PROTEIN CORE) The protein coat that encloses the viral genome is called Protein capsid. It may be of

different shapes and mainly made up of proteins sub units called “capsomeres”

(C)VIRAL ENVELOPES In some viruses accessory structure called Viral Envelopes are present that help them

in infecting their host. They are membranes that enclose the protein core.



TAILS AND TAIL FIBRES

Many viruses possesses thread like long tail and tail fibers. These structures help in

infecting the host. FIGURE / 5.5 (THE STRUCTURE OF BACTERIOPHAGE)

PAGE # 91

CLASSIFICATION OF VIRUSES

(A)ON THE BASIS OF MORPHOLOGY Viruses are generally classified on the basis of Morphology and nucleic acids they

contain. e.g. On the basis of morphology, Viruses are classified into rod shape (TMV),

spherical (Polio Virus) and Tadpole (Bacteriophage Virus).

(B) ON THE BASIS OF MODES OF ORIGIN Viruses can be classified on the basis of their mode of origin, which provide a

systematic idea of some of their diversity. Following are the main characteristics of

these groups:

1. Unenveloped plus strand viruses.

2. Enveloped plus strand RNAViruses.

3. Minus strand RNA Viruses.

4. Viroids

5. Double strand RNA Viruses.

6. Small genome DNA Viruses.

7. Medium genome and large genome DNA Viruses.

8. Bacteriophage.

LIFE CYCLE OF THE BACTERIOPHAGE

The virus that infects the bacteria (mostly E.coli) is known as “Bacteriophage”

Bacteriophage can reproduce by two alternative mechanisms.

1.The lytic cycle

2.The Lysogenic cycle.

(1)THE LYTIC CYCLE

The life cycle of the bacteriophage that eventually ends in death of the host cell is

known as “A LYTIC CYCLE”

The following are the stages of lytic cycle.

1. Initially the bacteriophage uses his tail fibers to stick to specific receptor present on

the outer surface of E-coli bacteria.

2. The sheath of the viral tail contracts, thrusting a hollow core through the bacterial

wall and membrane of the bacterial cell and then phage injects its DNA into the cell.

3. The empty capsid of the phage is left outside the cell.



4. The bacterial cell’s DNA is destroyed (hydrolyzed).

5. The phage DNA takes control over the bacterial metabolic machinery and uses it to

produce phage proteins and viral nucleotide.

6. Copies of the phage genome are developed and different parts of the phage come

together forming daughter phages.

7. In the last stage of lytic cycle the daughter phages released, hydrolytic enzymes

“lysozymes”, which digest the bacterial cell wall.

8. Due to osmosis, bacterial cell swells and finally burst releasing 100-200 daughter

phage particles.

FIGURE 5.6 (THE LYTIC CYCLE OF PHAGE-T4) PAGE # 94

2. THE LYSOGENIC CYCLE The life cycle of the Bacteriophage in which the viral genome replicates without

destroying the host cell is known as lysogenic cycle.

Viruses that are capable of using both modes of reproduction with in a bacterium are

called “Temperate Viruses”.

The following are the stages of lysogenic cycle.

(1) In this cycle infection of the E-coli cell begins when the phage binds to the surface

of cell and injects its DNA.

(2) With in the host cell, the phage DNA molecule forms a circle.

(3) The DNA molecules of Viruses incorporated by genetic recombination into a

specific site on the host cell’s chromosome. Now it is known as “Prophage cycle”

(4) The phage genome is mostly silent with in the bacterium.

(5) When E-coli cell prepares to divide, it replicates the phage DNA also, and passes

the viral copies to the daughter cells.

(6) This mechanism enables the virus to propagate with out killing the host cell upon

which it depends.

At some point, prophage give rise to the active phages that lyses their host cells. It is

usually an environmental trigger such as radiations, or the presence of certain

chemicals that convert the virus from the lysogenic to the lytic mode.

FIGURE 5.7 PAGE # 95

VIRAL DISEASES

1.ANIMAL DISEASES

(1) Poliomyelitis.

(2) Colds

(3) Encephalitis.

(4) Dengue fever.

(5) Yellow fever.

(6) AIDS



(7) Rabies.

(8) Measles.

(9) Mumps.

(10) Hepatitis.

2. PLANT DISEASES

(1) Tobacco Mosaic Virus (TMV) (Tobacco leaves disease) or (Tobacco Mosaic

Disease)

AIDS

CAUSITIVE AGENT

AIDS is stand for Acquired Immuno-Deficiency Syndrome, caused by Human

Immune Deficiency Virus (HIDV)

SYMPTOMS

(1) Short flu like illness.

(2) Pneumonia like conditions.

(3) Disfiguring form of Skin Cancer (Kaposi’s Sarcoma)

(4) Weight loss and fever.

(5) Dementia (loss of thoughts)

(6) Diarrhea (loose motion with increasing frequency)

(7) Septicemia (Blood Poisoning)

Severity of the Immuno-Deficiency varies and bouts of illness may persist for years.

HIV mostly infects lymphocytes and causes brain cell damage, in more than 50% of

cases. Irreversible dementia and eventual death occurs.

TRANSMISSION

(1) The HIV virus can only survive in the body fluids and transmitted by blood or

semen.

(2) In 90% of cases the transmission occurs by sexual contact. Some other modes of

transmission are as follow:

Unsterilized syringes and needles mostly in intravenous drug abusers.

By giving blood or blood products already infected with HIV.

Close contact between infected and non-infected people.

From an infected pregnant women to her baby through placenta or through breast

milk.

CONTROL AND TREATMENT

No particular drug is available for treatment of AIDS but there are some drugs, which

are effective against this disease like Azidothymadine, Zidovudine and sumarin.



PREVENTION

Use of the clean needles and sterilize syringes.

Education and public awareness about the disease and restricted sexual contacts with

preventive measures.

Tranfusion of screened blood and blood products.

HEPATITIS

Hepatitis is an inflammation of the liver cells caused by viral infections, toxic agents

or drugs.

SIGNS AND SYMPTOMS

Jaundice.

Abdominal pain.

Liver enlargement.

Fatigue and fever.

TYPES OF HEPATITIS

There are various types of Hepatitis few of them are as follow:

(1)HEPATITIS “A”

Cause by non-enveloped RNA virus.

Transmitted by contact with faeces from infected individual.

Most common form of Hepatitis world wide.

(2)HEPATITIS “B” (SERUM HEPATITIS)

Caused by DNA viruses.

More common in Asians, Africans and male homosexuals.

Often persist in carrier form without causing any symptoms.

Transmission mostly occurs through skin contacts, blood transfusion and other

medical procedures. (Surgery, NG tube, Catheters)

The virus of this disease can cause liver cancer mostly in carriers.

TREATMENT AND PREVENTION

New vaccines against the virus have been produced which are of great importance

especially for person who required frequent blood transfusion.

(3)HEPATITIS “C”

Transmission occurs through mother to child during pregnancy.

By sexual contacts.

Most common transfusion associated Hepatitis.

It causes liver cancers more often than HBV.



Chapter-6

BACTERIA

DISCOVERY

Bacteria was discovered by A.V. Leuwenhoek in 1676.

STRUCTURE OF BACTERIA

Bacteria are smallest and simplest living organism measures from 0.2m to 2 micron in

breadth and 2 to 10 micron in length. They are strictly unicellular but some species

remain associated with each other after cell division and form colonies.

A generalized bacterial cell consists of following structures.

(1)FLAGELLA They are extremely thin appendages, which originate from basal body, a structure in

the cytoplasm beneath cell membrane. Flagella help in bacterial locomotion.

(2)PILLI

They are hollow, filamentous flagella like appendages, which help in conjugation but

not in locomotion.

(3)CAPSULE

It is a protective sheath made up of polysaccharides and proteins. It provides greater

pathogenicity and protects bacteria against phagocytosis.

(4) CELL WALL Bacterial cell wall mostly made up of amino acids, sugar and chitin. It surrounds the

cell membrane, determine shape and protects bacteria from osmotic lyses. Most

bacteria have a unique macromolecule called Peptidoglycan in addition to it. Sugar

molecules, teichoic acid, glyco proteins and lipo polysaccharide are also present.

(5)CELL MEMBRANE

It is present inside the cell wall attached to it at few places containing many pores.

It is made up of lipids and proteins.

It acts as a respiratory structure.

(6)CYTOPLASM Bacterial cytoplasm is granular containing many small vacuoles, glycogen particles

and ribosomes.

(7)MESOSOMES



These are the invaginations of the cell membrane into the cytoplasm.

They are in the form of vesicles, tubules or lamella.

They help in the DNA replication, cell division, respiration and export of enzyme.

(8)BACTERIAL HEREDITARY MATERIAL

Bacterial hereditary material DNA is found as concentrated structures called Bacterial

chromosomes or chromatin bodies. It is mostly scattered in the cytoplasm.

A small fragment of extra chromosomal circular DNA, called Plasmid is also present.

FIGURE 6.1 (FROM TEXT BOOK)

CLASSIFICATION OF BACTERIA

ON THE BASIS OF SHAPE

On the basis of shape bacteria can be divided into four categories.

(1)COCCI

These are spherical or rounded bacteria presents in the form of mono, diplo or

streptococcus form.

They are non-flagellated and cannot move from one place to another place.

FIGURE (FROM TEXT BOOK)

(2)BACILLI

Bacilli are rod shaped bacteria, can be present in the form of diplo or streplobacilli.

They may be flagellated and can move from one place to another.


(3)SPIRILLA

These are spiral or cork, screw shape bacteria also known as spirochetes.

It includes chlamydia and rekettia.


(4)VIBRIO OR COMMA

These are slightly curved bacteria like vibrio cholera.

They may be flagellated and can move.

ON THE BASIS OF RESPIRATION

On the basis of respiration bacteria can be divided into two main types.



(1)AEROBES Require oxygen for respiration.

(2)ANAEROBES Respire with out oxygen

Sub-classes of this classification are as follow:

(A)FACULTATIVE BACTERIA Respire with or without oxygen.

(B)MICRO AEROPHILIC BACTERIA

Require low concentration of oxygen for growth

(C)OBLIGATE ANAEROBES These bacteria only survive in absence of oxygen.

(D)FACULTATIVE ANAEROBES These bacteria use oxygen but can respire with out it .

bThese bacteria only survive in the presence of oxygen.

ON THE BASIS OF NUTRITION

Bacteria can be divided into four main types on the basis of nutrition. Which are as

follow.

(1)SAPROTROPHIC BACTERIA

These bacteria depend on the dead organic matter for their nutrition.

They are mostly present in the humus of soil and posses large number of enzymes that

convert complex substances of humus to simpler compounds.

(2)SYMBIOTIC BACTERIA

These bacteria are found associated with other living organism.

They obtain their food from the host without harming it. E.g. Rizobium redicicola

(Symbionts in the root nodules of pea family plants).

(3)PARASITIC BACTERIA

These bacteria grow inside the tissues of other living organism

They obtain food at the expense of their host.

These bacteria lack certain complex system of enzymes therefore they usually depend

upon host cell. E.g. Pneumococcus, Mycobacterium tuberculosis, Salmonella typhi.



(4)AUTOTROPHIC BACTERIA

These bacteria can sythesize organic compound from simple inorganic substances.

Autotrophic bacteria can be divided into photosynthetic or chemosynthetic.

(A)PHOTOSYNTHETIC

These bacteria contain green pigment chlorophyll, which is known as bacterial

chlorophyll, or chlorobium chlorophyll.

These pigments are present in mesosomes (invagination of the cell membrane in the

cytoplasm)

These bacteria utilize H2S during photosynthesis instead of water and liberate sulphur

instead of oxygen.

sunlight

(B) CHEMOSYNTHETIC

These bacteria obtain their energy from oxidation of some inorganic substances like

iron, hydrogen, nitrogen and sulphur compounds.

LOCOMOTION IN BACTERIA

Some bacteria can move from one place to another with the help of a wipe like

structure flagella.

Flagella allow bacteria to disperse into new habitats, to migrate towards nutrients and

to leave unfavorable environment.

Flagellated bacteria show orientation towards various stimuli, a behavior called Taxis.

Some bacteria are chemo tactic, phototectic or magnetotatic.

GROWTH IN BACTERIA

In favorable conditions bacteria can grow, very rapidly. There are some factors

affecting growth of bacteria such as Temperature, nutrient availability, PH and ion

concentration. Bacterial growth can be divided into four main phases, which are as

follows

(1)LAG PHASE

It is inactive phase during which bacteria prepare them for division.

(2)LOG PHASE

In this phase bacteria grow and multiply very rapidly.

(3)STATIONARY PHASE

In this phase bacterial multiplication is equal to bacteria death rate.



(4)DECLINE/DEATH PHASE In this phase death is more rapid then multiplication rate.

REPRODUCTION IN BACTERIA

Usually asexual reproduction is present in bacteria which is as follow

FISSION

Fission is the fastest mode of bacterial asexual reproduction (Binary Fission)

It usually takes place in favorable conditions.

Hereditary material DNA in the form of chromatin body replicates.

After the replication of hereditary material a constriction appears in the middle of the

cell, which later splits it into two parts.

Newly form bacterial cells grow in size and form nature bacterial cells.

The single fission takes place in 20-30 minutes.

ENDOSPORE FORMATION

It is the method of bacterial survival under unfavorable conditions. Following are the

main characters of this process.

During this process, the whole protoplasmic content gets shrink into a small mass.

A cyst is formed inside the parental wall around constricted protoplasm to form

endospore.

On the return of favorable conditions parental wall raptures due to decay and

endospore is set free.

In the end, this endospore enlarges to form a mature bacterial cell.

FIGURE 6.4 (BINARY FISSION IN BACTERIA)

FIGURE 6.5 (FORMATION OF ENDOSPORE)

GENETIC RECOMBINATION IN BACTERIA

Genetic changes with the help of which bacteria adopt new characteristics (drugs

resistance pathogenic ability) is known as Genetic recombination

Three types of genetic recombination are present in bacteria, which are given as

follow.

1.CONJUGATION

Simple process of genetic recombination in which genetic material is transferred from

one bacteria to another through a conjugating tube. Conjugation in bacteria was

discovered by Joshua Lederburg and Edward L.Tatum in 1946



EXPERIMENT J.laderberg and E.Tatum performed an interesting experiment in order to prove

conjugation in bacteria. Following are the main steps of this experiment.

1. They selected a wild type bacteria (E-coli) and obtain (triple nutritional mutants)

different from one another.

2. Wild-type was capable of synthesizing six substances symbolized as A, B, C, D, E

and F.

3. Mutant type I was capable of synthesizing three substances symbolized as A, B and

C but not D, E and F.

4. Mutant type II was capable of synthesizing three substances D,E and F but not A,B

and C.

5. These mutant type I and II were grown together in the growth medium having all

the six substances A, B, C, D, E and F.

6. After several hours, three types of bacteria were detected after nutritional test which

were,

i. Both mutant I and mutant II types.

ii. Wild type bacteria synthesizing all the six substances.

iii. A new type of bacterial strain requiring all the six substances for growth.

In this experiment, appearance of wild type and one new type is an evidence that

conjugation had taken place.

2. TRANSDUCTION

It is the mode of genetic recombination in which genetic material is transferred from

one bacteria to another by a third party, which is usually bacteriophage.

This process was experimentally carried out by Lederberg and Zinder in 1952.

EXPERIMENT

1. In this experiment, a bacteriophage is made to attack a bacterium known as “donor”

(D).

2. The injected DNA of bacteriophage multiply to form a large number of daughter

phages.

3. The donor bacterium (D) gives some of its genetic material “D” to the multiplying

particles.

4. The phages released from this donor bacterium contain the genetic material of

phage plus a little piece of the donor genetic material “D”.

5. These new phages then made to attack a new bacterium known as “Recipient” (R).

6. These recipient bacterium is not destroyed like the donor in order to reproduce

normally. In this way, genetic material of the donor bacterium is carried to the

recipient bacterium by a bacteriophage and this process is known as Transduction.



3. TRANSFORMATION

In this process, genetic information transfers from one bacteria to another by

producing a change it (undergo a change).

This type of genetic recombination was first proved by Fred Griffith in 1928.

EXPERIMENT Griffithi injected a small quantity of R-type bacteria and a large quantity of heat killed

S-type bacteria into the same mouse.

This treatment proved fatal as mouse surprisingly suffered from Pneumonia and died.

The autopsy of the mouse revealed the presence of living S-type bacteria in the mouse

in addition to R-type.

From this experiment Griffith concluded that,

The live R-type bacteria had been transformed into live S-type bacteria due to transfer

of some material from dead S-type, cells.

Thus this transformation occurred due to genetic recombination in R-type bacteria.

In his experiment, he had been working on two strains of bacteria “Pnemococcus”.

One strain is known as smooth type (Virulent and causes Pneumonia) while the

second strain is known as (Rough type (Non-Virulent and does not cause pneumonia).

NOTE: (IMPORTANCE OF BACTERIA (USEFUL AND HARMFUL

BACTERIA)FROM BOOK PAGE # 116 (OLD BOOK – 2003)

VACCINATION

DEFINITION

Inoculation of host with inactive or weaken pathogens or pathogenic products to

stimulate protective immunity.

In case of subsequent natural infection with the same pathogen the immune system

easily recognized the invader and comfortably managed to overcome the pathogen.

A vaccine can taken orally (Polio vaccine) or injected into the body (Tetanus

Vaccine).

IMMUNIZATION

DEFINITION It is a process of induction of specific immunity by injecting antigens, antibodies or

immune cells.

Immunity can be protective or curative in nature.

It promotes increased immunity against specific diseases.

CYNOBACTERIA (BLUE GREEN ALGAE)

MAIN CHARACTERISTICS OF CYNOBACTERIA



They are prokaryotic unicellular autotrophic organisms mostly occur in colony form.

They posses double layered cell wall.

The protoplasm differentiated into an outer colored region chromoplasm, which

contain various pigments in which chlorophyll “a” and phycocyanin are more

important.

Inner colorless region of the protoplasm is known as centroplasm.

They are mostly aquatic (fresh water)

Sexual reproduction is absent.

Asexual reproduction takes place by means of Harmogonia, zoospores, akinates and

fragmentation.

NOSTOC

Nostoc is a typical example of blue green algae.

STRUCTURE

Nostoc is a filamentous prokaryotic algae in which filaments are intermixed in a

glatinous mass-forming ball like structure known as coenobium.

A single filament look like a chain of beads.

Each filament is unbranched and has a single row of rounded or oval cells.

Each cell has double layered wall, outer thick wall is made up of cellulose mixed up

with pectic compounds. While inner thin layer is made up of cellulose only.

The protoplasm is differentiated into an outer colored region (chromoplasm) and an

inner colorless region (centroplasm).

The chromoplasm various pigments like chlorophyll, axanthophylls, carotene,

phycocyanin and phycoerythrin.

Ribosome’s, pseudovacuoe and reserve food in the form of cynophyceae starch are

present.

Hereditary material is present in cytoplasm with out the nuclear membrane.

In Nostoc filaments slightly larger, colorless cells with thick walled known as

“Heterocyst” are present. The function o Heterocyst is nitrogen fixation, food storage

and multiplication of filament during unfavorable conditions.

NUTRITION

It is an autotroph and prepares its food in the presence of sunlight.

It also capable of fixing atmospheric nitrogen and converts it into nitrates in order to

prepare amino acids and proteins, this activity takes place in Heterocysts.

REPRODUCTION

Only asexual reproduction is present which takes place by following methods.

(1)HORMOGONIA



A portion of the filaments between two heterocysts is known as Hormogonia.

During favorable conditions, filaments break up at the junction of each Heterocyst.

The end cells of each homogonous divide to form long filaments of Nostoc.

(2)AKINETES

It is the method of survival during unfavorable conditions.

These are non-motile spores, formed from certain vegetative cells.

Each akinete contains an outer layer “exospore” and inner layer “endospores”.

On the return of favorable conditions, each akinete germinates by rupturing exospore

and formed independent filaments by simple cell division.

IMPORTANCE OF CYNOBACTERIA

They release oxygen as a by-product during photosynthesis.

Many are capable of fixing atmospheric nitrogen.

They are first colonizers of moist soil.

Nostoc anabena is used as nitrogen fertilizer in agriculture due to its nitrogen fixing

ability.

MONERA

Discovery of bacteria A.V.Leuventoek.

Size of bacteria = 0.2-2 micron (breadth)

= 2-10 micron (length).

Cell wall of bacteria made up of peptidoglycan.

Arch bacteria do not contain peptidoglycan.

Bacterial replications, cell division, respiration, export of enzymes = By means of

mesosomes (invaginations of cell membrane)

Saprophytic bacteria form humus (important component of soil)

Photosynthetic bacteria = use H2S in photosynthesis instead of water.

Chlorobium chlorophyll or bacterial chlorophyll discovered by Von Nell 1930.

DIVERSITY OF LIFE

Father of taxonomy = Charles Linneus.

Genetics = final tool in classifying living organism.

Basic unit of Biological classification = species.

Five kingdom system of Robert Whittaker = 1969.

Discovery of Virus = Iwanosky 1892.

TMV Virus discover by Wendell Stanley in 1935.

Size of Virus = 20nm-250nm.

AIDS is caused by Human Immune Deficiency Virus (HIV)

As a result of lytic cycle of bacterio phage 100-200 daughter phage viruses are

produced.



Chapter-7

PLANT LIKE PROTOCTIST

ULVA: (SEA-LETTUCE)

OCCURANCE

Ulva, commonly called Sea Lettuce, is a marine green alga.

It is found attached to rocks, along the sea coast in intertidal zones (the area between

the high tide and low tide mark)

In Karachi, it is found on Manora coast.

STRUCTURE

Ulva exhibits primitive simple multicellular organization.

The plant body is a thallus, which is flat, erect , wrinkled and sheet like structure

having a length of about 30 cm (1ft).

The thallus is very thin and internally it is composed of two vertical rows of cells

only.

Its lower part forms a “hold fast”, consisting of long thread like cells for attachment to

the substratum.

REPRODUCTION

Ulva can reproduce sexually as well as asexually.

(1)SEXUAL REPRODUCTION

Sexual reproduction is isogamous and takes place in sexual plants or gametophyte,

which are haploid (n).

Each cell of the gametophyte produces many biflagellate gametes, which are released

in seawater.

The gametes are morphologically similar or isogametes but the fusion takes place

between gametes produce by two different gametophyte plants, which are termed as

positive strain and the negative strain.

Thus, ulva plant exhibits heterothallism (two type of plant body i.e. gametophyte (n)

and sporophyte (2n) ulva).

After fusion a diploid quadri flagellate zygote is formed.

Zygote swims for some time then loses its flagella, secretes a wall around itself and

undergoes a period of rest.

Finally the zygote germinates and develops into a new diploid ulva plant, which is

called asexual plant or sporophyte.

(2)ASEXUAL REPRODUCTION

Asexual reproduction takes place by formation of quadri flagellate zoospores in

diploid asexual plant or sporophyte, which is morphologically similar to gametophyte.



Each cell (except the basal cells) of the sporophyte (2n) undergoes meioses or

reduction division and forms 8-16 zoospores, which are released in water.

After swimming they lose flagella and undergo a period of rest.

Each zoospore ultimately developes and forms haploid sexual plant i.e. gametophyte,

thus completing the life cycle.

ALTERNATION OF GENERATION

A distinct regular alternation of generations between the haploid gametophytes

(sexual plant) and diploid sporophyte (asexual plant) is present. Since the two plants

are morphologically similar so this process is known as “Alternation of generation

(isomorphic)”

CHLORELLA

FIGURE 7.2 PAGE # 127.

OCCURANCE

Chlorella is a fresh water alga found floating in stagnant water of ponds, pools and

ditches.

It is easily cultured and has been used an experimental organism in research in

photosynthesis.

STRUCTURE

The body of chlorella is one celled, spherical in outline and solitary.

It contains a single nucleus and a cup-shaped chloroplast usually with out pyrenoid.

REPRODUCTION (ASEXUAL REPRODUCTION)

Reproduction takes place by aplanospore formation, which involves the division of

protoplast into 8-16 daughter protoplast.

Each daughter protoplast secrets a wall to produce a non-motile aplanospore.

On release from the parent cell, each aplanospore forms a new vegetative cell.

IMPORTANCE

Recently an antibiotic known as “Chlorellin” useful for the control of bacterial

diseases has been prepared from the plant.

FUNGI LIKE PROTOCTIST

SLIME MOLD (PLASMODIUM STAGE)

In initial stages of life cycle, slime mold are creeping masses of living substances,

having the consistency of an unboiled egg white and the colour of the yolk.

It sends out protoplasmic arms that engulf and digest bacteria from the surface of

rotten rock or leaves.

This amoeboid stage of slime mold is called plasmodium stage.



The plasmodium consists of the cytoplasm in which are embedded many nuclei, food

vacuoles and undigested food particles.

Plasmodia can move along the forest floor, on to dead leaves that are bathed in

sunlight.

FRUITING BODY

In dry warm environment metamorphosis in Plasmodia takes place and it changes into

cluster of fruiting bodies.

Depending on the species the fruiting bodies look like golf balls, feathers, bird cages

or worm like and in a great variety of colours.

REPRODUCTION

Each fruiting body produces a large number of microscopic asexual reproductive cells

known as spores.

Each spore has a single nucleus and a thick protective wall.

Germination of the spore occurs when there is plenty of water and suitable

temperature.

When a slime mold’s spore germinates, it produces one or more tiny cells.

Each cell has a pair of flagella that propel it through the film of water, which is

necessary for its germination.

These flagellated cells some times function as gametes (sex cells) and fuse in pairs.

This is true sexual reproduction.

Fusion of the gametes forms zygote, which become amoeboid and form a new

plasmodium i.e. multinucleated slime mold

PHYTOPTHORA INFESTANS(WATER MOLD)

This fungi like protoctist belongs to family Oomycotes.

It is a pathogenic organism causing. “late blight of potato”

STRUCTURE

The mycellium consist of Hyphae which are endophytic, branched, aseptate

coenocytic, hyaline and nodulated.

The rounded or branched hustoria are found which absorb food material from the host

cells.

REPRODUCTION

Sexual as well as asexual reproductions are present.

(A)ASEXUAL REPRODUCTION

Asexual reproduction takes place by means of biflagellate zoospores produce inside

the productive structure Sporangia.

The spores are produced on the branched Sporangiophore in favorable condition.



Sporangiophore coming out through the stomata, in groups on the lower surface of

infected leaves.

The sporangia are produced on the branches of sporangiophore.

On maturation, the sporangia the detached from sporangiophore.

On maturation the protoplasm of the sporangium converts into uninucleate,

vacuolated and naked zoospores.

When mature sporangium burst the zoospores liberate in the film.

(B)SEXUAL REPRODUCTION

Sexual reproduction is zoogamous.

The female sex organ is oogonium. while the male sex organ is antheridium.

The antherialium develops first and the oosgonium later.

Both sex organ may develop on he same Hyphae or on two adjacent Hyphae lying

side by side.

The oogonium hyphae penetrates the antheridium.

The oogonium is pear shaped and contains a single female nucleus in it.

The fertilization takes place when the male and the female nuclei fuse in the egg after

penetration of the oogonium in the antheridium.

There is no fertilization tube and after fertilization the thick walled zoospore

developed, which is present inside the oogonium.

The oospore germinates in favorable conditions and produce new mycellium.

Reduction division occurs during germinates of oospore.

ECONOMIC IMPORTANCE

The Water Mold causes a disease in potato crop known as “late blight of potato”

This disease effects both aerial and underground parts and whole plant becomes

blighted in severe conditions.

The disease appears in the form of brown spread patches on leaves and rapidly

increases to the whole leaf surface.

The tuber converts into a rotten pulpy mass emitting foul smell and remains small in

size.

A great danger to potato crop and causes sufficient damage of Potato crop.

EUGLENA

Euglena is an unicellular, flagellated organism. It belongs to the division

“Euglenophyta”

OCCURANCE

Euglena commonly found in drains, ponds and is also present in soil, blackish water

and even salt water.



DUEL NATURE

Euglena has characteristics of both animals and plants.

It is more evolved than green Algae.

STRUCTURE

1. It is somewhat elongated animal, almost pointed at both ends.

2. It has definite and easily stainable nucleus.

3. It has well defined chloroplast as in higher plants.

4. All the Euglena have two flagella usually one of them is long and the other one

short by which they can swim activity.

5. They lack the outer cellulose cell wall, instead the protoplasm is bounded by a

grooved layer called the “Pellicle”.

6. Euglena has a gullet near the base of the flagella and an eyespot containing a

pigment called “Astaxanthin”.

7. Reproduction is usually asexuality by simple division.

TAXONOMIC POSITION OF EUGLENA

One of the examples of Eukaryotes is Euglena.

Belongs to group kingdom Protactista.

PLANT LIKE CHARACTERS IN EUGLENA

1. Presence of Chloroplast.

2. Undergoes physiological, biochemical process of photosynthesis.

3. Behaves as natural autotroph in presence of sunlight.

ANIMAL LIKE CHARACTERS IN EUGLENA

1. Absence of a cell wall.

2. Presence of a mouth with cytopharynx.

3. Eyespot containing animals pigment called “Astaxanthin”.

4. Presence of reservoir.

5. Can easily be converted into heterotopy after the loss of chloroplast.

ANIMAL LIKE PROTOCTISTA

PHYLUM PROTOZOA

GENERAL CHARACTERS

1. Protozoa are microscopic, unicellular (as single cell performs all vital activities)

organisms.

2. These organisms are asymmetrical.

3. The body of organism may be naked or covered by pellicle to maintain the shape.



4. Cytoplasm of protozoans is usually divided into outer, ectoplasm and inner granular

endoplasm.

5. Cell may be uninucleate or multinucleate. Nuclei are covered by nuclear

membrane.

6. Protozoan may be solitary or colonial.

7. They are aquatic and are found in both fresh and marine water.

8. Nutrition may be holozoic (animal like), halophytic (plant like) or saprozoic

(subsisting in dead organic matter) or parasitic.

9. Digestion is intracellular and is accomplished inside the food vacuole.

10. Locomotion takes place by flagella, cilia or psendopodia.

11. Respiration takes place through general body surface.

12. One or more contractile vacuoles are present for osmo-regulation.

13. Reproduction takes place by both asexual and sexual methods.

14. The asexual methods include binary fission, multiple fission and budding.

15. Sexual reproductive methods include gamete formation (Isogamies and

Anisogamous) or by conjugation.

CLASSIFICATION

About 30,000 species of protozoa are divided into five classes, which differ in their

means of locomotion.

1. Class flagellate (Mastigophora).

2. Class sarcodina (Rhizopoda).

3. Class ciliate (Ciliophora).

4. Class suctoria.

5. Class sporozaa.

(1)CLASS FLAGELLATA 1. Locomotary organs are long hair like “Flagella” with are one or two in number.

2. Body is enclosed in a thin covering of “Pellicle”.

3. Asexual reproduction takes place by longitudinal fission.

4. Class Flagella is divided into sub classes.

(A)SUB-CLASS PHYTOFLAGELLATA (PHYTOMASTIGMA)

Contain chlorophyll and perform process of photosynthesis.

Examples: Euglena and Volvax.

(B)SUB-CLASS ZOOFLAGELLATA (ZOOMASTIGMA)

Does not contain chlorophyll and are heterotrophic.

Examples: Trypanosome and Leis mania.

Some flagellates are parasites. For example: Trypanosome is a blood parasite human

and causes African sleeping sickness. Its carrier is “Tse Tse fly”.

(2)CLASS SARCODINA (RHIZOPODA)



1. Locomotion takes place by “Psendopodium”.

2. Body shape is not definite and keep on changing because the pellicle is absent.

Some have external sheats or skeletons.

3. Nutrition is mostly holozoic, some are parasite. E.g. Entamoeba, histolytic can

cause human dysentery.

4. Example:

i. Entamoeba histolytic is a parasite living in intestine of man. ii. Foraminifera is a

group including shelled sarcodimians. E.g. Polystomella. iii. Heliozoa is a group

including fresh water organisms having fine, stiff and ray like psendopodia e.g.

Actinophrys.

(3)CLASS CILIATA 1. Locomotory organs are cilia which are short, thin, protoplasmic structure, covering

the body surface.

2. Body shape is definite and maintained by pellicle.

3. Many ciliates have a groove or depression called “Gullet” into which food can be

brought.

This class is divided into two sub-classes.

(i) SUB-CLASS PROTOCILIATA

Cilia all of equal size and uniformly distributed.

Cytosomes absent.

Nuclei two to many but all of one type e.g. Opalina

(ii) SUB-CLASS ENCILIATE

Cilia of different types and not uniformly distributed.

Cytosomes usually present.

Nuclei of two types types Micronucleus and Meganucleus e.g. Paramecium,

Balantidium.

(4)CLASS SUCTORIA 1. They are closely related to ciliates, therefore both are includes in same sub-phylum

i.e. sub phylum Ciliphora.

2. Young individual have cilia and swim about but the adults are sedentary and have

stalks by which they are attached to the substrate.

3. Body bears a group of delicate cytoplasmic tentacles, some of which are pointed to

pierce their prey, where as others are tripped with rounded adhesive, knobs to catch

and hold the prey.

4. The tentacles secrete a toxic material which may paralyze the prey.

5. Suctorians have two nuclei i.e. meganucleus and micronucleus.

6. Reproduction is by asexual budding. E.g. Acineta, Ephelota.



(5)CLASS SPOROZOA 1. All are parasites.

2. Lomotary organs are absent.

3. Body covered by a thick cuticle.

4. Asexual reproduction is by multiple fission or sporulation.

5. Sexual reproduction is isogamies or anisogamous.

6. Examples.

i) Plasmodium is a human blood parasite enters the human blood when an infected

female Anopheles mosquito bites humans. Plasmodium reproduces asexually in man

and sexually in the body of mosquito.

ii) Monocytis lives as a parasites in seminal vesicles of earthworm.

MALARIA

INTRODUCTION

“Malaria is an infectious disease marked by attacks of chills fever, sweating occurring

at intervals that depends on the time required for the development of a new generation

of parasites in the body”.

CAUSATIVE AGENT

Malaria is caused by a protozoan parasite of the genus PLASMODIUM. It was

discovered by LAVERAN in 1878.

TRANSMITTING AGENT

Malaria is transmitted into the blood of man by the bite of an infected “FEMALE

AND PHELES MOSQUITO”. It was discovered by KING in 1717.

SYMPTOMS OF MALARIA

The symptoms of malaria first appear after several days of infection in man. He time

taken by parasite before it appears in the blood is called INCUBATION PERIOD.

SYMPTOMS DURING INCUBATION PERIOD

The symptoms that appears in incubation period:

Nausea.

Loss of appetite.

Constipation.

Insomnia.

Headache.

Muscular pain.

Aches in joint develops.



USUAL SYMPTOMS OF MALARIA

Onset of malarial fever

Shauking chills

Sweating

Rise in body temp. (may be up 106?)

MALARIA – A BIOLOGICAL PROBLEM

Malaria has been one of the man’s most important biological problems. Millions of

people have been killed only because of his disease. To solve this problem, various

biological methods were applied to find out in details. Experiments were performed,

observation and data were collected, and finally the complete life cycle of the malarial

parasite was studied.

STUDYING MALARIA EXPERIMENTALLY

In the experimental study of malaria, several HYPOTHESIS were presented and

deductions were made for each of them. Experiments were performed to test the

deduction and observations are recorded. If the deductions are proved true, the

hypothesis regarded as correct.

HYPOTHESIS (1)

A hypothesis was made about the malarial parasite plasmodium that: “Plasmodium is

the cause of malaria”

DEDUCTION To test the above hypothesis, the following deductions were made: “If the

plasmodium is the cause of malaria, then the patients suffering from malaria should

have malarial parasite in their blood”.

EXPERIMENT Experiment were carried out by examining blood samples from malarial patients that

showed positive result. To prove it further experiments were repeated whenever

malaria accured.

RESULT

In this way the hypothesis that the “Plasmodium is the cause of malaria” was found to

be true.

HYPOTHESIS (II)

It was noted that people living around the marshy places were usually have the attack

of malaria. Thus the hypothesis was stated “Malaria is associated with marshes”



DEDUCTION To test the statements, a deduction was made that “If marshes are eliminated”.

EXPERIMENT On experimental basis, marshes were eliminated and as a result the role of infection of

malaria was greatly much reduced.

RESULT

It was this proved that malaria is associated with marshes. Thus the hypothesis stands

true. Thus, it is new understood that accurate methods are essential to understood

biological problems.

LIFE – CYCLE OF MALARIAL PARASITE

DISCOVERY

Life cycle of plasmodium in ANOPHELES MOSQUITO was first discovered in

1898.

PHASES OF LIFE CYCLE

The life cycle of plasmodium is digenetic involving two phases is two hosts for

completion.

1. ASEXUAL PHASE IN MAN (PRIMARY HOST)

2. SEXUAL PHASE IN MOSQUITO (SECONDARY HOST)

1. ASEXUAL CYCLE IN MAN (SCHIZOGONY)

INTRODUCTION

The life cycle of plasmodium in mass is Asexual and is called SCHIZOGONY,

because “SCHIZONTS” are produced.

PHASES OF SCHIZOGONY

According to Graham (1948), the life cycle of plasmodium can be divided into four

phases;

1. PRE-ERYTHROCYTIC PHASE (LIVER SCHIZOGONY).

2. ERYTHROCYTIC PHASE.

3. POST-ERYTHROCYTIC PHASE.

4. GAMORONY OR GAMETOCYTIC PHASE.

EXPLANATION OF SCHIZOGONY

INFECTION

A healthy person acquires infection when a female Anopheles mosquito, containing

infective stages (SPOROZOITES) of parasite is its salivary gland, bites him for

sucking his blood.



(1)PRE-ERYTHROCYTIC PHASE

Once with in the human blood, the sporozoites circulate in the blood for about half an

hour.

INVASION OF LIVER

After circulation in the blood, the sporozoites get into liver to invade the hepatic cells.

SCHIZONT FORMATION

After penetrating the liver cells, each sporozoite grows for no. of days and becomes a

SCHIZONT.

CRYPTOZOITE FORMATION

SCHIZONT divides to form a large number of uninucleate CRYPTOZOITES, which

are liberated when the liver cell burst.

METACRYPTOZOITE FORMATION

The released cryptozoites invade the fresh liver cells and multiply producing

enormous no. of metacryptozoites.

(2) ERYTHROCYTIC PHASE

TROPHOZOITE FORMATION

The metacryptozoites after escaping into the blood stream, invade the red blood

corpuscles. Each become rounded and is called TROPHOZOITE.

SIGNET RING STAGE

When trophozoite grows in size, the nucleus is pushed to one side into the peripheral

cytoplasm. It resembles a signet ring and is preferred to an SIGNET RING STAGE.

MEROZOITE FORMATION

The trophozoite ingesis a large amount of cytoplasm of the R.B.C. The blood H6 is

broken down into its protein components, which is used by trophozoite develops into

an active amoeboid trophozoite. After active feeding, it becomes rounded and grows

in size and become and SCHIZONT. It now undergoes SCHIZOGONY and produces

MEROZOITES.

RELEASE OF MEROZOITES IN BLOOD

With the rupture of RBC’S, the merozoites are liberated into the blood plasma. These

invade fresh corpuscles to repeat the cycle. The time taken to complete one

erythrocytic cycle depends upon the species of Rasnodium.

(3) POST-ERYTHROCYTIC PHASE

Some merozoites produced in erythrocytic phase reach the liver cells and undergo

schizonic development. This is known as Post-Erythrocytic Phase.

(4) GAMOGONY

FORMATION OF GAMETOCYTES

When successful asexual multiplication is achieved, the merozoites donot proceed



further with the erythrocytic phase but, after entering the RBC, increase in size to

form Gamocytes.

TYPES OF GAMETOCYTES

Gametocytes are of two types:

1. Male Microgamo Cycle

2. Female Macrogamo Cycle

The Gametocytes do not divide, but remain within the host blood until they are

injected by the vendor, in which they continue their sexual development.

SEXUAL CYCLE IN MOSQUITO

INTRODUCTION Sexual life cycle of Plasmodium is completed in the gut of Female Anopheles

Mosquito resulting in infective Sporozoites. This cycle is completed in 12-23 days.

PHASES OF SEXUAL CYCLE

This cycle comprises of following stages:

1. Gametogony

2. Syngamy or Fertilization

3. Sporogony

EXPLANATION OF SEXUAL CYCLE

(1) GAMETOGONY

Gametogony refers to the Formation of Gametes. The gamocytes are taken up along

with the blood into the stomach of the mosquito and develop into gametes.

FEMALE MACROGAMETE

The female gamocytes soon become macrogamete, which is larger in size and ready to

fertilize.

MALE MICROGAMETE

Each male gamocyte forms 6 to 8 sperms like microgametes by a process of

Exflagellation.

(2) SYNGANY OR FERTILIZATION

ZYGOT FORMATION

Within the gut of mosquito the two gametes of opposite sexes fuse together to form a

zygot. This process is called Syngamy.

OKINETE FORMATION

After fertilization zygot differentiates into motile worm-like ookinete.

OOCYST FORMATION

Ookinete penetrates the stomach wall to settle down just under the mid gut. Here after



observing nutrients, it develops a cyst around it and becomes spherical. This encysted

is called Oocyst.

(3) SPOROGONY The oocyst then enters a phase of asexual multiplication, the Sporogony.

SPOROBLAST FORMATION

In 6 to 7 days, the nucleus of oocyst divides into several nuclei and cytoplasm

envelops each one of them and thus hundreds of oval shaped Sporoblasts are formed.

SPOROZOITE FORMATION

The sporoblast nucleus again divides and forms hundreds of filamentous, uninucleated

Sporozoites. The cyst bursts and liberated sporozoites migrates to the Salivary Gland

where they await to penetrate to a human host.

Chapter-8

KINGDOM FUNGI

“Fungi are a group of unicellular to multicellular, thalloid, heterotrophic, eukaryotic

living organisms having a body called MYCELLIUM, made up of HYPHAE which

are non-chlorophyllous & have cell wall (made up of chitin). Reproduction is usually

ASEXUAL by means of spores”.

FUNGI ARE NEITHER COMPLETELY PLANTS NOR ANIMALS

Previously fungi were regarded as plants as they resemble the plants in many

characteristics. But in addition fungi have many qualities just like the animals. So they

are regarded in the midway between plants and animals.

PLANT LIKE CHARACTERISTICS OF FUNGI

Fungi resemble the plants in

Having Cell Wall

Lacking Centrioles

Being non-motile

ANIMAL LIKE CHARACTERISTICS OF FUNGI

But Fungi also resemble with animals as they are

Heterotrophic

Lack cellulose in their cell wall

Presence of chitin

It means that

Fungi are neither completely plants nor animals.



CONFIRMATION

Detail studies also confirm that Fungi are different from all other organisms.

NUCLEAR MITOSIS

They have a characteristic mitosis called Nuclear-mitosis, during which nuclear

membrane does not break & spindle is formed with in the nucleus.

SOME REPRESENTATIVES OF KINGDOM FUNGI

Some imp. Examples are as follows:-

YEAST

MUSHROOMS

PENICILLIUM

MOLD

MUCOR

RHIZOPUS

STRUCTURE OF BODY OF FUNGUS

MYCELIUM

The complete multicellular body of fungus is called MYCELIUM, which is composed

of white fluffy mass of branched hyphae.

HYPHAE

A few of true fungi are unicellular (such as yeast) but most have multicellular body

(mycelium) consisting of long, slender, branched, tubular, thread like filaments called

as Hyphae which spread extensively over the surface of substrate.

HYPHAE

TYPES OF HYPHAE

Hyphae can be divided in to two types:

1. Septate or Multicellular Hyphae

2. Non-septate or multinuclear or coenocytic hyphae.

1.SEPTATE HYPHAE

DEFINITION

“Those hyphae which are separated by cross-walls called “septa” into individual cells

containing one or more nuclei , are called “Septate Hyphae”

EXAMPLE: Mushrooms



2. NON-SEPTATE HYPHAE

DEFINITION Those hyphae, which lack septa & are not divided into individual cells, instead these

are in the form of long, multinucleated large cells are called Non-septate or

Coenocytic Hyphae.

EXAMPLE Mucor & Rhizopus

CELL WALL OF HYPHAE

CHITIN is the chief component present in the cell wall of most fungi, Because it is

more resistant to decay than are the Cellulose & lignin which make up plant cell wall.

CYTOPLASM OF HYPHAE

In septate Hyphae —– Cytoplasm flows through the pores of septa from cell to cell,

carrying the materials to growing tips & enabling the hyphae to grow rapidly, under

favorable conditions. In non-septate hyphae —— cytoplasm moves effectively,

distributing the materials throughout.

NUCLEI OF HYPHAE

All fungal nuclei are HAPLOID except for transient diploid zygote that forms during

sexual reproduction.

MAIN FUNCTION OF HYPHAE

Extensive spreading system of Hyphae provides enormous surface area for absorption.

NUTRITION IN FUNGI

ABSORPTIVE HETEROTROPHS

All fungi lack chlorophyll & are heterotrophs ( obtain carbon & energy from organic

matter, They obtain their food by direct absorption from immediate environment &

are thus “ABSORPTIVE HETEROTROPHS”.

DIFFERENT MODES OF HETEROTROPHIC NUTRITION IN FUNGI

Being Heterotrophic, fungi can exist as

1- Saprotrophs or saprobes ( Decomposers )

2- Parasites

3- Predators

4- Mutualists



1. SAPROBIC OR SAPROTROPHIC FUNGI ( DECOMPOSERS)

Saprobic fungi along with bacteria, are the major decomposers of biosphere,

contributing to the recycling of the elements (C,N,P,O,H & etc) used by living things.

DEFINITION

“Those fungi which obtain their food (energy, carbon & nitrogen), directly by

digesting the dead organic matter are called “SAPROBIC FUNGI” OR

“DECOMPOSERS”

MECHANISM OF ABSORBING FOOD (DEVELOPMENT OF RHIZOIDS)

These fungi anchor to the substrate by modified hyphae, the RHIZOID, which provide

enormous surface area for absorptive mode of nutrition.

SECRETION OF DIGESTIVE JUICES Saprobic fungi secrete digestive juices, which digest organic matter & the organic

molecules thus produced are absorbed, back into the fungus.

2. PARASITIC FUNGI

DEFINITION Those fungi which absorb nutrients directly from living host cytoplasm are called

PARASITIC FUNGI.

MECHANISM

For obtaining, their food requirements, these fungi develop specialized hyphal tips

called as HAUSTORIA which penetrate the host tissues for absorbing nutrients.

TYPES OR PARASITIC FUNGI

Parasitic fungi may be of two types

A. OBLIGATE PARASITES

B. FACULTATIVE PARASITES.

(A) OBLIGATE PARASITES

DEFINITION

Those parasitic fungi which can grow only in their living host & cannot be grown on

available defined growth culture medium, are called “ Obligate Parasites”.

EXAMPLES Many mildews

Most of Rust species.



(B) FACULTATIVE PARASITES

DEFINITION “Those parasitic fungi which can grow parasitically on their host as well as by

themselves on artificial growth media, are called “ Facultative Parasites”.

3. PREDATORY FUNGI

DEFINITION

“Those fungi which obtain their food by killing other living organisms are called

PREDATORY FUNGUS

EXAMPLES 1. Oyster Mushrooms ( Pleurotus astreatus ).

2. Some species of Arthrobotrys.

MECHANISM OF OBTAINING FOOD

1. IN OYSTER MUSHROOMS Oyster mushroom is a carnivorous fungus. It Paralyses the nematodes (that feed on

this fungus), penetrate them & absorb their nutritional contents, primarily to fulfill

nitrogen requirements. It fulfill it glucose requirements by breaking the woods.

2. IN ARTHROBOTRYS Constrictor ring development

Some species of Arthrobotrys trap soil nemotodes by forming CONSTRICTING

RING, their hyphae invading & digesting the unlucky victim.

4. MUTUALISTIC FUNGI

DEFINITION

“Those fungi which form such symbiotic associations with other living organisms in

which both partners of association get benefit from each other are called

MUTUALISTIC FUNGI & Such association are called as “MUTUALISTIC

SYMBIOTIC ASSOCIATIONS”

TWO MUTUALISTIC SYMBIOTIC ASSOCIATIONS FORMED BY FUNGI

Fungi form two key mutualistic symbiotic associations. These are:

1. LICHENS

2.MYCORRHIZAE



1. LICHENS

SYMBIOTIC PARTNERS IN LICHENS Lichens are mutualistc & have symbiotic associations b/w certain fungi (mostly

Ascomycetes) & imperfect fungi & few Basidiomycetes (about 20 out of 15000

species of lichens) & certain photoautotroph either green algae or cynobacterium or

sometimes both.

MUTUAL BENEFIT In lichens, fungi protect the algal partner from strong light & desiccation & itself gets

food through the courtesy of alga.

AREAS WHERE LICHENS GROW

Lichens can grow at such places such as bare rocks & etc, where neither of the

components alone can grow.

ECOLOGICAL IMPORTANCE OF LICHENS From ecological point of view, lichens are very important because they serve as BIO

INDICATORS of AIR POLLUTION.

2. MYCORRHIZAE

SYMBIOTIC PARTNERS

Mycorrhizae are mutualistic association b/w certain fungi & roots of vascular plants

(about 95% of all kinds of vascular plants).

MUTUAL BENEFIT The fungal hyphae dramatically increase the amount of soil contact & total surface

area for absorption & help in direct absorption of nutrients from soil. The plant on the

other hand, supplies organic carbon to fungal hyphae.

TYPES OF MYCORRHIZAE There are two main types of mycorrhizae.

1. Endomycorrhizae

2. Ectomycorrhizae

1. ENDOMYCORRHIZAE

In Endomycorrhizae, the fungal hyphae penetrate the outer cells of plant root, forming

coils, swellings & minute branches, & also extend out into surrounding soil.

2.ECTOMYCORRHIZAE In Ectomycorshizae the hyphae surround & extend between the cell but don’t

penetrate the cell walls of roots.



EXAMPLE

Mutualistic association between fungi & pines & firs

REPRODUCTION IN FUNGI

Two kinds of reproduction are usually found in Fungi

1. ASEXUAL REPRODUCTION

2. SEXUAL REPRODUCTION

Except In perfect Fungi in which sexual reproduction has not been observed.

1. ASEXUAL REPRODUCTION

DEFINITIION

The most common means of reproduction in fungi which does not involve sexes,

reduction division & fertilization is called A SEXUAL REPRODUCTION

DIFFERENT MODES OF ASEXUAL REPRODUCTION

In fungi , asexual reproduction take place by following ways:

1- SPORE FORMATION

2- CONIDIA FORMATION

3- FRAGMENTATION

4- BUDDING.

1- SPORE FORMATION

INTRODUCTION It is the most common type of asexual reproduction in fungi in which large no of

spores are developed with in the sporangia. Each spore on generation produces

another mycelium.

EXPLANATION OF THE PROCESS

SPORES

Spores may be produced by sexual or asexual process, are haploid, thick walled, non-

motile & not needing water for their dispersal, They are very small & produced in

very large no. with in the SPORANGIUM.

SPORANGIUM

Spores are produced inside the reproductive structures called SPORANGIA, which

develop as swellings at the tips of SPORANGIOPHORES.

SEPARATION OF SPORANGIUM FROM HYPHAE

After the formation of spores, sporangium becomes separated from hypae by a

complete septa.

BREAKAGE OF SPORANGIAL WALL

On maturity of the spores, the outer wall of sporangium breaks down & spores are

dispersed.



DISPERSION OF SPORES

Spores are usually dispersed by air currents to great distances & cause wide

distribution of many kinds of fungi. They may also be dispersed by small animals &

insects & by rain splashes.

GERMINATION OF SPORES

In a favorable condition, on a proper substrate, the spore germinates giving rise to new

fungal hyphae.

2.CONIDIA FORMATION

INTRODUCTION

The type of asexual reproduction in fungi in which large number of asexual spores

called “CONIDIA are formed, each on germination giving rise to new mycelium is

known as CONIDIAL REPRODUCTION.

EXPLANATION

CONIDIA

Conidia are non-motile, asexual spores which may be produced in very large number

& can survive for weeks, causing rapid colonization on new food.

CONIDIOPHORES

Conidia are not developed inside the sporangium but they are usually cut off at the

end of modified hyphae called CONIDIOPHORES, commonly in chains or clusters.

EXAMPLE Asexual reproduction by conidia formation is very common in ASCOMYCETES.

3.FRAGMENTATION

It is the type of asexual reproduction in which mycelium of some fungal hyphae

breaks into pieces or fragments. Each fragment develops into a new mycelium.

4. BUDDING

INTRODUCTION Budding is an asymmetric asexual division in which tiny outgrowth or bud is

produced which may separate & grow by simple relatively equal cell division into

new mycelium.

EXAMPLE Unicellular yeasts reproduce by budding

SEXUAL REPRODUCTION

INTRODUCTION

Details of sexual reproduction very in different groups of fungi on the basis of which



fungi can be divided into four major phyla, However the fusion of haploid nuclei &

meiosis are common to all.

EXPLANATION Sexual reproduction in fungi takes place through several stages, which are as follows.

PLASMOGAMY

When fungi reproduce sexually, hyphae of two genetically different but compatible

mating types come together & their cytoplasm fuse. This process is called

PLASMOGAMY, This step is common in all types of fungi.

IN ZYGOMYCOTA

In Zygomycota after Plasmogamy following steps occur.

KARYOGAMY

In zygomycetes, Plasmogamy is followed by fusion of nuclei, called as

KARYOGAMY

ZYGOT FOMATION & MEIOSIS

In ZYGOMYCETES, fusion of nuclei, leads directly to the formation of zygot, which

divides by meiosis when it germinates.

IN ASCOMYCOTA AND BASIDIOMYCOTA

In these groups of fungi, following steps after plasmogamy.

FORMATION OF DIKARYOTIC NYPHAE

In these groups, the two genetic types of haploid nuclei from two individuals my

coexist & divide in the same hyphae for most of the life of fungus. Such as fungal

hyphae is called DIKARYOTIC OR HETEROKARYOTIC HYPHA/CELL.

FORMATION OF FRUITING BODIES

Extensive growth of dikaryotic hyphae may lead to the formation of massive

structures of interwoven hyphae called as Fruiting Bodies, such as

Basidia/ Basidiocarps

Asci/ Ascocarps

SYNGAMY & MEIOSIS

Fusion of two haploid nuclei occurs with in the fruiting bodies forming a zygote, This

is called as SYNGAMY, followed immediately by meiosis.



FORMATION OF HAPLOID SEXUAL SPORES

Each zygote divides immediately by meiosis to form four haploid spores, which when

release are dispersed, some of them giving rise to new hyphae.

CLASSIFICATION OF FUNGI

There are four major divisions of fungi, which are divided on the basis of their sexual

reproduction.

1- ZYGOMYCOTA

2- ASCOMYCOTA

3- BASIDIOMYCOTA

4- DEUTEROMYCOTA

1- ZYGOMYCOTA

INTRODUCTION Zygomycota are by far the smallest of four groups of fungi, with only about 600

named species. This group includes more frequently bread molds as well as a variety

of other microscopic fungi found on decaying organic material.

CHARACTERISTIC FEATURE The group is named after a characteristic feature of the life cycle of its member, the

production of temporalily dormant structures called ZYGOSPORES.

The zygomycetes lack septa in their hyphae i.e coenocytic hyphae, except when they

form sporangia or gametangia.

LIFE CYCLE OF ZYGOMYCOTA

In the life cycle of zygomycota, two types of reproduction occurs:

A- SEXUAL REPRODUCTION IN ZYGOMYCOTA

B- ASEXUAL REPRODUCTION IN ZYGOMYCOTA

(A) SEXUAL REPRODUCTION IN ZYGOMYCOTA Sexual reproduction takes place by fusion of GAMETANGIA in following steps:

FORMATION OF PROGAMETANGIUM

When two hyphae came in contact with each other, each of them gives a lateral

progametangium, facing each other.

DIFFERENTIATION OF PROGAMETANGIA INTO GAMETANGIA &

SUSPENSORS

Later on, each of the progametangium differentiates into two parts

Apical swollen part called GAMETANGIUM, containing numerous nuclei

Basal hollow part called SUSPENSOR.



GAMETANGIAL COPULATION The gametangia may be formed on hyphae of different mating types or on a single

hyphae. If different mating types are involved, fusion between pairs of haploid nuclei

occurs immediately.

ZYGOT FORMATION Fusion of haploid nuclei results in formation of diploid zygote nuclei, Except for the

zygote nuclei, all nuclei of zygomycota are haploid.

ZYGOSPORE FORMATION

After the formation of diploid zygote nuclei, the fused portion of hyphae develops into

ZYGOSPORES.

GERMINATION OF ZYGOSPORE

Under favorable condition zygospore germinates & giving rise to new mycelium.

Meiosis occurs during germination.

(B) ASEXUAL REPRODUCTION IN ZYGOMYCOTA (BY SPORE

FORMATION )

Asexual reproduction occurs much more frequently than sexual reproduction in the

zygomycetes.

EXPLANATION

As previously discussed in spore formation

EXAMPLES OF ZYGOMYCETES

1- MUCOR

2- RHIZOPUS STOLONIPER

2-ASCOMYCOTA

INTRODUCTION The second division of fungi, the ASCOMYCOTA is a very large group of about

30,000 named species with many more being discovered each year.

CHARACTERISTIC FEATURE The ascomycota are named for their characteristic reproductive structure, the

microscopic, club shaped ASCUS.

TYPE OF HYPHAE

The hyphae of ascomycetes are divided by septa i.e septate hyphae, but the septa are

perforated & the cytoplasm flows along the length of each hyphae. The septa that cut



off the asci & conidia are initially perforated like all other septa, but later they often

become blocked.

LIFE CYCLE OF ASCOMYCOTA

In life cycle of ascomycota, Both sexual & asexual reproduction occurs.

(A) SEXUAL REPRODUCTION IN ASCOMYCOTA

Sexual reproduction occurs through following steps.

1-FORMATION OF MALE GAMETANGIUM OR ANTHERIDIUM

The hyphae of ascomycetes may be either homokaryotic & heterokaryotic. The cells

of these hyphae usually contain from several to many nuclei. These cells form

Antheridium or male gametangium.

2-FEMALE GAMETANGIUM OR ASCOGONIUM The gametangium which develop beak like out growth called as TRICHOGYNE, is

called female gametangium or Ascogonium.

3-FUSION OF MALE & FEMALE GAMETANGIUM When antheridium is formed , it fuses with trichogyne of an adjacent ascogonium.

Fusion of cytoplasm or plasmogamy occurs.

4-PAIRING OF NUCLEI After plasmogamy, nuclei from antheridium then migrate through the trichogyne into

the ascogonium, & pair with nuclei of opposite mating types.

5-FORMATION OF DIKARYOTIC HYPHAE & DIKARYOTICY

Dikarytic hyphae then arise from the area of fusion. Throughout such hyphae, nuclei

that represent the two different original mating types occur ( DIKARYOTICY ) Such

hyphae are also called as HETEROKARYOTIC HYPHAE.

6-FORMATION OF ASCOCARPS OR FRUITING BODIES

Excessive growth of monokaryotic or dikaryotic hyphae results in formation of

massive structures of tightly interwoven hyphae, called as FRUITING BODIES OF

ASCOCARPS, which corresponds to the visible portions of a morel or cup fungus.

7- ASCI FORMATION Asci are special reproductive structures which are formed on special fertile layers of

dikaryotic hyphae with in the Ascocarps.



8- SEPARATION OF ASCI -+The asci are cut off by the formation of septa at the tips of heterokaryotic hyphae.

9- SYNGAMY There are two haploid nuclei with in each ascus one of each of which belongs to

different mating type. Fusion of these two nuclei occurs within each ascus called as

SYNGAMY.

10-ZYGOT FORMATION Syngamy results in zygote formation, which divides immediately by meiosis, forming

four haploid daughter cells.

11- FORMATION OF ASCOSPORES Four haploid daughter nuclei, usually divide again by mitosis , producing 8 haploid

nuclei that become walled & called ASCOSPORES.

12-BURSTING OF ASCUS

In most Ascomycetes, the ascus becomes highly turgid at maturity and ultimately

bursts, often at a perforated area, which may be pore or slit or lid

13- DESPERSION & GERMINATION OF ASCOSPORES After bursting, the ascospores may be thrown as far as 30 cm. Under favorable

circumstances they germinate giving new hyphae.

TYPES OF ASCOCARPS IN ASCOMYCETES

According to their shape, Ascocarps are of following three types:

1- OPOTHECIUM

The ascocarps of cup fungi & the morels are open, with the asci lining the open cups

called OPOTHECIUM.

2- CLEISTOTHECIUM Some ascocarps are closed & called as ‘CLESTOTHECIUM’

3- PERITHECIUM Some ascocarps have small opening at the apex called as PERITHECIUM. Ascocarps

of NEUROSPORA are of this type.

(B) ASEXUAL REPRODUCTION IN ASCOMYCOTA (BY CONDIA

FORMATION)

INTRODUCTION

The type of asexual reproduction in fungi in which large number of asexual spores



called “CONIDIA are formed, each on germination giving rise to new mycelium is

known as CONIDIAL REPRODUCTION.

EXPLANATION

CONIDIA

Conidia are non-motile, asexual spores which may be produced in very large number

& can survive for weeks, causing rapid colonization on new food.

CONIDIOPHORES

Conidia are not developed inside the sporangium but they are usually cut off at the

end of modified hyphae called CONIDIOPHORES, commonly in chains or clusters.

EXAMPLE Asexual reproduction by conidia formation is very common in ASCOMYCETES.

3.BASIDIOMYCOTA

INTRODUCTION

The basidiomycetes, third division of fungi have about 16,000 named species. More is

known about some members of this group than about any other fungi.

CHARACTERISTIC FEATURE Basidiomycetes are named for their characteristic sexual reproductive structures, the

BASIDIUM, which is club shaped like as ascus.

LIFE CYCLE OF BASIDIOMYCOTA

In life cycle of Basidiomycota, reproduction is usually sexual. Asexual reproduction is

not very important.

(A) SEXUAL REPRODUCTION IN BASIDIOMYCOTA The life cycle of basidiomycetes begin with the production of hyphae which may be

of two types.

1- Homokaryotic hyphae giving rise to primary mycelium.

2- Heterokaryotic hyphae giving rise to secondary mycelium.

PRIMARY OR MONOKARYOTIC MYCELIUM Homokaryotic or monokaryotic hyphae lack septa at first. Eventually, However, septa

are formed between nuclei of these hyphae. A basidiomycete mycelium made up of

monokaryotic hyphae is called PRIMARY MYCELIUM.

SECONDARY OR DIKARYOTIC MYCELIUM Mycelium of basidiomycetes, with two nuclei, representing the two different mating

types b/w each pair of septa, is called SECONDARY OR DIKARYOTIC



MYCELIUM. Most of the mycelium of basidiomycetes that occur in nature is

dikaryotic & often only dikaryotic mycelium is able to form basidiocarps.

FORMATION OF BASIDIOCARP OR FRUITING BODY

Dikaryotic mycelium is responsible for the formation of FRUITING BODY in

Basidiomycetes called as BASIDIOCARP, made up of tightly interwoven dikaryotic

hyphae.

FORMATION OF BASIDIUM

Basidium is characteristic reproductive structure of Basidiomycetes, which is club

shaped & formed with in the Basidiocarp. This produces slender projection at the end

called as STERIGMATA, in this way.

SYNGAMY & ZYGOT FORMATION Nuclear fusion or syangamy occurs in Basidium, giving rise to diploid zygote, the

only diploid cell of the life cycle.

MEIOSIS & BASIDIOSPORE FORMATION

Meiosis occurs immediately after the formation of zygot, resulting in the formation of

four haploid nuclei, which are incorporated in Basidiospores. In most member of this

division basidiospores are borne at the sterignata

DISPERSION AND GERMINATION

Same as in Ascomycetes

(B) ASEXUAL REPRODUCTION IN IN BASIDIOMYCOTA

In contrast to their effective sexual reproduction, asexual reproduction is rare in most

basidiomycetes.

EXAMPLES OF BASIDIOMYCETES

MUSHROOMS

TOAD STOOLS

PUFF BALLS

JELLY FUNGI

SHELF FUNGI

PLANT PATHOGENS CALLED RUSTS & SMUTS,

4.DEUTEROMYCOTA (FUGI IMPERFECTI)

INTRODUCTION “The fungi that are classified is this group, are simply those in which the sexual

reproductive stages have not been observed. In other words, most of the Fungi

Imperfecti are as ascomycota that have lost the ability to reproduce sexually. There

are some 17000 described species of this group.”



CHARACTERISTIC FEATURE

Sexual reproduction is absent among Fungi Imperfecti

LIFE CYCLE OF DEUTEROMYCOTA

Although in life cycle of deuteromycetes or Fungi Imperfecti, true sexual reproduction

is absent, but there is certain type of GENETIC RECOMBINATION which seems to

be responsible for some of the production of new pathogenic strains of wheat rust.

GENETIC RECOMBINATION IN FUNGI IMPERFECTI PARASEXUALITY

In parasexuality, exchange of portions of chromosomes between the genetically

distinct nuclei with in a common hyphae takes place. This is the special type of

genetic recombination occurs in fungi Imperfecti.

EXAMPLES OF FUNGI IMPERFECTI Among the economically important genera of Fungi Imperfecti are

1-PENICILLIUM

2- ASPERGILLUS

3- Most of the fungi that cause skin diseases in humans, including athlete’s foot &

ring worm are also fungi imperfecti.

ECONOMIC IMPORTANCE OF FUNGI

Fungi play a vast role in economic field they show both harmful & useful activities to

human beings.

USEFUL FUNGI

Following are some of the beneficial effects of fungi.

FOOD

Many kinds of edible fungi are in the form of mushrooms, are a source of nourishing

& delicious food dishes. But not all the mushrooms are edible. Some of them are

poisonous & called as toad stools or death stool. Yeast, another kind of fungi, are

utilized in baking industry.

MEDICINES

Nearly two dozens antibiotics have been isolated from different types of fungi &

bacteria, like

Penicilliun from penecillium notatum

Neomycin

Chloromycetin

Tetramycin & etc.



FOOD PRODUCTION Many kinds of Yeast are used in the production of bakery & brewery products. Some

species of genus PENICILLIUM give characteristic flavors & aromas to the cheese.

FERMENTATION

Species of Aspergillus, are used for fermenting soya sauce & soya paste. Citric Acid

is produced commercially with members of this genus under highly acidic condition.

SOIL FERTILITY Fungi maintain the soil fertility by decomposing the dead organic matter e.g

Mycorhizal fungi.

PRODUCTION OF ORGANIC COMPOUNDS

May species of fungi are used in the production of organic compound such as

vitamins, proteins & fats. Saccharomyces, synthesizes a range of vitamin B group.

HARMFUL FUNGI

Following are some of the harmful effects of fungi,

FOOD SPOILAGE Saprophytic fungi cause tremendous amounts of spoilage of food stuff. 15-20% of

worlds fruit is lost each year due to fungal attack.

SPOILAGE OF WOOD & LEATHER ARTICLES Many fungi spoil leather goods, woods, wool, books, timber, cotton & etc. WOOD-

ROTTING FUNGI destroy not only living trees but also structural timber.

BRACKET/SHELF FUNGI cause lot of damage to store cut lumber as well as stands

of timber of living trees.

TOXINS

Many fungi are poisonous . AMANITA VERNA is a mushroom, which produces

deadly poisonous substance known as AMANITIN, which causes serious problems in

respiratory system & blood circulatory system.

FOOD POISONING Some fungi during decomposing food release certain poisonous substances

collectively known as MYCOTOXINS. Mycotoxins are the major source of food

poisoning.

DISEASES Fungi cause a number of diseases in plants as well as in human beings.



PLANT DISEASES CAUSED BY FUNGI Fungi destroy many agricultural crops, fruits, ornamentals & other kinds of plants

because they produce several enzymes that can breakdown cellulose, Lignin and even

cutin. Following are some of the serious plant disease caused by Fungi.

RUST & SMUT DISEASES Rust & smut diseases are serious diseases of WHEAT, RICE, CORN &other cerial

crops. They cause extensive damage.

POTATO BLIGHT

A serious disease of potato caused by a fungus known as PHYTOPTHORA

INFESTANS. Other plant disease are.

Powdery mildews ( on grapes, rose, wheat & etc).

Ergot of rye

Red rot of sugar cane

Potato will

Cotton root rot

Apple scab

Brown rot of peaches, plums, apricots & cherries.

ANIMAL DISEASES CAUSED BY FUNGI

Following are some of the fungal diseases in man.

SKIN DISEASES

RING WORM & ATHELETE’S FOOT are superficial fungal infection caused by

certain Fungi Inperfecti

ORAL THRUSH CANIDIA ALBICANS, a yeast causes oral & Vaginal thrush.

ASPERGILLOSIS Aspergillosis is the disease of ear & lungs caused by ASPERGILLUS. It occurs only

in person with defective immune system such as AIDS & cause death.

CANCER Some strains of ASPERGILLUS FLAVUS produce one of the most carcinogenic (

cancer causing ) mycotoxins called AFLATOXINS.

ERGOTISM

Ergotism is caused by eating bread made from PUROLE ERGOT- Contaminated

flour. The poisonous material in the ergot causes nervous spasm, convulsions,

psychotic delusion & even gangrene.



HISTOPLASMOSIS

Histoplasmosis is a serious disease of lungs caused by inhaling spores of a fungus,

which is common in soil contaminated with bird’s feces.

Chapter-10

MAIN CHARACTERISTICS

Animals of this phylum show following important characters.

NATURE

Most simple multicellular organisms. From evolutionary point of view they occupy a

position between protozoa and true metazoa

HABIT AND HABITAT

Mostly marine but few in fresh water habitat.

They are sessile, living attached to rocks, coral and other hard surfaces

SHAPE AND STRUCTURE

Their shape may be cylindrical, branching, globular, flat, bell shaped or cup shaped.

Some are dull in colour and most are brightly coloured.

The body is perforated by pores and canals.

MICROSCOPIC STRUCTURE

Most of sponges contain following types of cell:

(A) PINACOCYTES

Forming the epidermis.

(B) POROCYTES

Form pores of the body wall

(C) CHOANOCYTES

These are flagellated cells, form the internal lining of the body. These cells are

strikingly similar to the choano flagellates.

Much of the body is composed of jelly like matrix containing a skeleton made of

Protein, CaCO3 or silica.

Sponges are organized on cellular level, instead of a single cell carring on all the life

activities.

Sponges show cellular differentiation but little or no coordination of cells to form

tissues.

They usually have an endoskeleton of separate spicules.



They do not posses a head, an interior end, a mouth or gut cavity.

They are sedentary organisms ranging in size from 1 to 200cm.

DIGESTION

Digestion takes place with in the cell. (Intracellular)

PROCESS OF FEEDING, EXCRETION AND RESPIRATION

Sponges feed by filtering out bacteria and fine particles of organic matter from water.

The flagella of “Choanocytes” beat and create a current of water.

The water current also helps in respiration, removal of waste products and dispersal of

gametes.

REPRODUCTION

Reproduction is of both type asexual and sexual

Asexual reproduction is by means of “Buds” and “Gemmules formation”.

Sexual reproduction is by means of sperm and ova.

All sponges appear to be diploid and have the usual metazoan process of “Oogenesis”

and “Spermatogenesis”.

The eggs retained just beneath the choanocytes where they are fertilized by sperm

from another sponge brought in with the current of water.

Fertilization is internal.

LARVA

After cleavage, the larva escape from the parent to the open sea as a free swimming

“Amphiblastula larva”.

It finally becomes attached to the bottom by its anterior end.

Reproduction is also by fragmentation.

BODY CAVITY

Body cavity is known as “Spongocoel”.

EXAMPLES

Common examples are

1. Sycon

2. Euplectella

3. Euspongia

MAIN CHARACTERS

HABIT AND HABITAT

They are aquatic animals, mostly marine and few fresh water forms. They are

sedentary or free swimming and solitary or colonial



STRUCTURE

The cnidarians are metazoan having the simplest type of body wall consisting of two

layers. The outer epidermis and the inner gastro dermis which lines the body cavity.

In between the two layers lies the mesogloa, non-cellular jelly secreted by them.

Cnidarians, due to their two layers body wall are termed as diploblastic animals. All

other metazons possesses a third layer called mesoderm in their body wall, laying in

between the epidermis and gastrodermis (Endoderm) and are therefore called

Triploblastic animals.

They have radially symmetrical body plan organized as a hollow sac.

The mouth is surrounded by a circle of tentacles bearing cnidoblasts stinging cells

containing nematocysts.

They have central digestive cavity connected to the outside by mouth.

STRUCTURAL TYPES

The Cnidarians are radially symmetrical and occur in two types of forms.

(a) The polyp

(b) The Medusa

(A) POLYP

The polyp like Cnidarian for example sea anemone has a cylindrical body with a

mouth directed upwards and surrounded by tentacles. The basal surface of the body is

attached to the substratum.

(B) MEDUSA

The medusa like Cnidarians jelly fish are umbrella like in appearance. Their oral

surface, bearing the mouth is directed downwards. Whereas the aboral surface is

directed upward. The medusoid Cnidarians are usually free swimming.

PROCESS OF FEEDING AND DEFENCE

The Cnidarians feed mostly on animal diet.

The food is digested in the gut and the waste products are expelled through the mouth.

The Cnidarians so named, because they possess cnidoblasts bearing nematocysts

which help in feeding and defence.

REPRODUCTION

The Cnidarians reproduce by asexual as well as sexual methods. Polypoid Cnidarians

possess a remarkable ability to regenerate.

(A) REGENERATION



If the oral part of the body is lost. The remaining part regenerates the new mouth and

the whole of tentacles.

(B) ASEXUAL REPRODUCTION

A sexual reproduction takes place by Budding.

(C) SEXUAL REPRODUCTION

The sexual reproduction takes place through male or female gametes which are

usually produced by different parents.

The gametes develop in the interstitial cells and aggregate in gonads which are located

either in the epidermis or in the gastodermis.

The fertilized egg gives rise to “Planula Larva”

CLASSIFICATION OF CNIDARIA (COELENTERATA)

The Phylum Cnidaria is divided into three classes:

1. Hydrozoa

2. Scyphozoa

3. Anthozoa

1. HYDROZOA

As the most primitive class of the Cnidarians, Hydrozoa is thought by some

evolutionists to have given rise to both other classes. They show following

characteristic features:

They are mainly marine, but some are fresh water species

Many species have both polyp and medusa

For e.g:

Hydra, Obelia and Physalia

2. SCYPHOZOA

Most of animals of this class are commonly called “Jelly Fish”.

They are semitransparent and are of various colours.

Most are of marine habitat.

For e.g:

Aurelia and Cyanea (largest Jelly Fish)

3. ANTHOZOA

These animals are mostly marine.

Solitary or colonial Polyp forms are present.

Medusa stage is absent.

Gastrovascular cavity is divided into chambers, increase area for digestion.



For e.g:

Sea-anemones and Corals etc

GENERAL CHARACTERS

HABIT AND HABITAT

The Echinodermates are exclusively marine including the largest invertebrate “Giant

Squids.”

EXTERNAL FEATURES

Symmetry usually radial, nearly always pentamerous.

Body shape is rounded to cylindrical or star like.

Surface of the body is rough.

Body wall consists of an outer epidermis, a middle dermis and inner lining of

peritoneum.

INTERNAL FEATURES

Endoskeleton consists of closely fitted plates forming shell usually called “THECA,”

may be composed of separate small “OSSICLES.”

Coelom is spacious, lined by peritoneum and occupied mainly by digestive and

reproductive systems.

Presence of “Water Vascular System” is most characteristic feature.

Alimentary tract is usually coiled.

Circulatory or Haemal or blood lacunar system is typically present.

Excretory system is wanting.

Nervous system is primitive, consists of ganglionated nerve cord.

Sense organs are poorly developed.

Sexes are usually separate.

Reproduction is usually sexual, fertilization is external.

WATER CANAL SYSTEM

Water canal system is unique in possessing an internal closed system of canals

containing a watery fluid.

REGENERATION

Regeneration of lost part is common

IMPORTANCE OF WATER CANAL SYSTEM

These canals are provided with tubular protrusions called “Tube Feet,” which serve a

number of functions like locomotion, anchoring to hard surfaces, grabbing the prey,

diverting food particles towards mouth and in some cases also respiration. The watery



fluid is drawn from the surrounding water through a perforated disc called the

“Madreporite.”

EXAMPLE

Star Fish, Brittle stars, Sea urchins, Sea-cucumbers, Sea-Dollar, Sea-lilies and Feather

stars.

LARVA

Bipinnaria larva

Chapter-11

DEFINITION

The capturing and conversion of energy from one form to another in the living system

and its utilization in metabolic activities is called Bioenergetics.

Bio-energetics is the quantitative study of energy relationships and conversion into

biological system. Biological energy transformation always obey the laws of

thernodynamic.

ROLE OF ATP AS ENERGY CURRENCY

ATP is adenosine triphosphate. Adenosine is made of adenosine and ribose sugar.

Among the three phosphate groups two are energy rich PO4 bonds. So ATP is a high

energy compound it gives its PO4 groups easily. When 1 ATP is converted into ADP,

7.3 K cal/mole or 31.81 KJ/mole energy is released. ATP -> ADP + Pi + Energy

Living organisms use organic food for generation of energy. These food usually

contain carbohydrates which degrade to produce CO2, H2O and energy. Which is

usually in the form of ATPs. ATP plays role in several endergonic and exergonic

reactions.

ENDERGONIC REACTIONS

Those chemical reactions which accompanied by the absorption of the energy are

known as endergonic reactions. The products have a higher free energy than reactants.

Examples of endergonic reaction in human are

1. Synthesis of proteins

2. Synthesis of lipids

3. Synthesis of cholestrol

4. Synthesis of glycogen

EXERGONIC REACTIONS

Those reactions which complete along with the liberation of free energy are known as

Exergonic reaction. The products have a lower free energy than the reactants.



EXAMPLE

An aerobic glycolysis, Kreb’s cycle, oxidative phosphoylation.

PIGMENTS

Substances in plants that absorb the visible light are called Pigments. Different

pigments absorb light of different wavelength. They are involved in the conversion of

light energy to chemical energy. Important plant pigments are chlorophyls,

carotenoids, phycobilin, xanthophylls, phaelophytin.

PHOTOSYSTEM

Each photosystem is a highly organized unit consisting of chlorophyll accessory

pigment molecules and electron carrier molecules present on the thylakoids of

chloroplast. Each thylakoid contains many units of two photosystems the photosystem

I and photosystem II. So chloroplast contains thousands of photosystem.

The photosystem consists of chlorophyll “a” and “b” and carotenoids. Chlorophyll

having empirical formula of C55H72O5N4Mg is almost identical to “Chlorophyll b”

of empirical formula C55H70O6N4Mg. But the slight

structural difference between them is enough to give 2 pigments slightly different

absorption spectra and hence different colours “Chlorophyll a” is blue green while “b”

is yellow green.

Hundreds of chlorophyll a, chlorophyll b and carotenoids cluster together in a

photosystem. But only a single molecule of chlorophyll a acts like a reaction centre

the rest of others absorbs a photon, the energy is transmitted from pigment, molecules

to pigment molecules until it reaches a particular chlorophyll a located in the region of

reaction centre, where it gives electrons to primary electron acceptor

FIGURE 11.3 PAGE 260

Hundreds of carotenoids are admixed with 2 types of chlorophyll molecules in

photosystem, giving yellow and orange shades. Carotenoids can absorb wavelength of

light that chlorophyll cannot transfer to chlorophyll a. Some times excess energy can

damage chlorophyll a, so carotenoids accept energy from them, thus providing a

function known as Photoreceptor.

ROLE OF LIGHT

Light has a dual nature, can behave like a wave or like a particle. It is composed of

packets of energy called photons (hu). Light energy captured in the light harvesting

complexes is efficiently and rapidly transferred to the chlorophyll molecules present

in the photosynthetic reaction centre. When a photon of light hits these chlorophyll a

molecules. The energy of these photons is absorbed and results in the elevation of an

e- from the ground state to an excited state, level depends upon the energy and

incident photon.

A photon of red light has enough energy to raise an electron to excited state I and this

energy is sufficient to carryout all the chemical reactions of photosynthesis.



The energy transferred by blue light raise the electron to excited state –2. However the

energy transmitted by red or blue photons to photosynthetic electron transport chain is

exactly the same. This is because that extra energy is lost (from absorption of blue

photon) by radiationless de-excitation.

The excitation energy can be used in

1. Photochemistry (i.e. it enter the photosynthetic electron transport chain)

2. Lost as heat.

3. Give fluorescence etc.

PHOTOSYNTHESIS

Photosynthesis is an anabolic process in which chloroplast of the plants take up CO2

and H2O and using light energy to synthesize carbohydrates. In photosynthesis, the

light energy is converted to chemical energy. It is an oxidation reduction process in

which water is oxidized and CO2 is reduced

6CO2 + 12H2O -> C6H12O6 + 6H2O + 6O2 ↑

In simple

6CO2 + 6H2O -> C6H12O6 + 6O2 ↑

This process divides into

1. Light reaction

2. Dark reaction

1. LIGHT REACTION

In the light dependent reactions, light energy is absorbed by chlorophyll and other

photosynthetic pigment molecules. It is then converted into chemical energy. Due to

this energy conversion, NADPH+ and ATP are produced.

Components of light reaction

1. Light capturing chlorophyll molecules.

2. Membrane bound protein complexes

3. Mobile electron carriers

CHLOROPHYLL MOLECULES AND PHOTOSYSTEM

Each photosystem consists of a light gathering “antenna complex” and a “reaction

centre”. The antenna complex has many molecules of chlorophyll a, chlorophyll b and

carotenoids most of them channeling the energy to reaction centre. Reaction centre of

photosystem I and II has one or two “chlorophyll a” molecules, primary electron

acceptor, associated electron carriers of electron transport system and certain specific

proteins known as chlorophyll-bound proteins which differs them from other

“chlorophyll a” molecules of the same system. The “chlorophyll a” molecules at the

reaction centre of photosystem I (PSI) has a maximum absorbance at 700 nm, while

those of PS II absorb at 680 nm. Therefore these reaction centre are called P700 and

P680 where P simply stands for pigment.



COMPLEXES

There are 4 major groups of complexes.

1. PS I

2. PS II

3. Cytochrome b/f complex

4. ATPase complex

The PS I and ATPase or ATP synthase complex are present on non-appressed region

of thylakoid. While PS II and light harvesting complexes (LHC II) are present on

appressed side. The cyt b/f complex is randomly distributed throughout the

mambrane.

MOBILE ELECTRON CARRIERS

Transport the excited electrons between the complexes. These are

plastoquinone (PQ) plastocyanin (PC), ferredoxin (FD)

ELECTRON TRANSPORT

This process occurs in several steps.

(1) EXCITATION OF PS II

When chlorophyll a of reaction centre of PS II is striked by a photon, the

energy of photon absorbs in it. This results in the elevation of an electron from the

ground state to an excited state. The excited electrons produced within P680 is rapidly

transferred to the primary electrons acceptors phaelophytin. So 2 electrons which are

transformed has to be replaced which is done by water.

(2) PHOTOLYSIS OF WATER

In the presence of light a water splitting enzyme complex extracts 4 electrons from

two water molecules. Removal of electrons splits the water into two hydrogen ions

2H+ and oxygen atoms. The extracted electrons from water are supplied to PS II

(P680) while the oxygen atom immediately combines with another oxygen atom to

form O2. Which is released during photosynthesis. The hydrogen ions or proton (H+)

are stored in thylakoid space. The overall reaction will be

2H2O -> 4 H+ + 4e- + O2

(3) FLOW OF ELECTRONS FROM PS II TO PS I

Photoexcited electrons accepted by phaelophytin from PS II are transferred to

plastoquinone molecules QA and QB which accept two electrons and takes up two

protein from the stroma. PQ carries electrons from PS II to cytochrome b/f complex

containing FeS protein. This is thought to be the rate limiting step of electron

transport. Electrons from PQ are taken up by Cyt b/f complex through FeS and



releasing protons (2H+) to the lumen. The second mobile electron carrier plastocyanin

(PC) takes the electrons and delivered to the photosystem I.

(4) FLOW OF ELECTRONS FROM PS I TO NADP+ REDUCTASE

A second excitation event within PS I leads to the transfer of electrons to the primary

electron acceptor. The primary e- acceptor of PS I passes the photoexcited electrons to

a second electron transport chain, which transmit then to ferredoxin, an iron

containing protein. An enzyme called NADP reductase then transfer the electrons

from Fd to NADP+ (oxidized form)

(5) REDUCTION OF NADP+ TO NADPH+ H+

This is the redox reaction that stores the high energy electrons in NADP+ to reduced it

to NADPH + H+.

NADP+ + 2H+ -> NADPH + H+

Hydrogen ions are taken from stroma which is being pumped from thylakoid space to

stroma by ATPase.

PHOTOPHOSPHORYLATION

Hydrogen ions are pumped into thylakoid space by cyt b/f and also 2H+ ions are

collected there from photolysis of one water molecule. This large no. of H+ ions in

thylakoid space compared to stroma, creates an electrochemical gradient, when these

hydrogen ions flow out of the thylakoid space by way of a channel protein present in

membrane called the ATP synthase complex, energy is prvided to it. The transport of

3 protons (H+ ions) through the ATPase complex are normally required to produce 1

ATP from ADP and inorganic phosphate Pi.

ADP + Pi -> ATP

This is called chemiosmotic ATP synthesis because chemical and osmatic events join

to permit ATP synthesis. The linear flow of electrons from H2O to NADP+, coupled

to ATP syntheses is non-cyclic photophosphorylation because the electrons pass on to

a terminal acceptor.

In cyclic photophosphorylation the electrons are cycled from PS I back to PQ. So only

ATP is produced but not NADPH + H+. This occurs under following conditions to

meet increased ATP demand for e.g. CO2 fixation

1. Protein synthesis

2. Synthesis of starch

EVENTS OF LIGHT REACTION

1. Photolysis of water.

2. Reduction of NADP+ to NADPH + H+

3. Synthesis of ATP by photophosphorylation.

So during light reaction ATP and NADPH + H+ are produced which are used in Dark

reaction, O2 is evolved as a by product.



2. DARK REACTION

The dark reaction consist of a series of light independent reactions which can proceed

even in the absence of light. During dark reaction, energy is produced by ATP and

NADPH+ H+ and CO2 is fixed in carbohydrates. This cyclic series of enzymatic

catalyzed reaction in the stroma of the chloroplasts is called Calvin-Benson Cycle.

During this cycle CO2 is reduced to triose-PO4 sugars, therefore this pathway is also

known as C3 pathray (reductive pentose phosphate cycle) and the plants undergo this

cycle are known as C3 plants. The calvin or C3 cycle is divided into 3 phases.

CARBOXYLATION (CARBON FIXATION)

The calvin cycle begins when a molecule of CO2 reacts with a highly reactive

phosphorylated five carbon sugar named ribulase 1.5 bisphosphate (RuBP). This

reaction is catalyzed by the enzyme ribulase biphosphate carboxylase or Rubisco (it is

the most abundant protein in chloroplast). The product of this reaction is a highly

unstable, six carbon intermediate that immediately breakdown into two molecules of

three carbon compound called 3-phosphoglycerate (G3P).

3CO2 + 3RuBP -> G3P

REDUCTION

Each molecule of the PGA or G3P receives an additional phosphate from ATP of light

reaction, forming 1,3-bisphosphoglycerate (G1,3P) which is then reduced to

glyceraldehydes 3-phosphate (GA3P) and Dihydroxyacetone phosphate (DHAP) by

NADPH+ H+GA3P and DHAP are intercovertible and the reaction don’t require any

energy. These products are also formed during glycolysis and links dark reaction with

sugar synthesis pathway.

6G3P + 6ATP + 6NADPH + H+ -> 6GA3P + 6ADP + 6NADP+ + 6Pi

REGENERATION

Three carbon compounds are rearranged to form five carbon units ribulose 1,5-

bisphosphate (RuBP), which is the primary carbon acceptors in the cycle.

5 GA3P + 3ATP -> 3 RuBP + 3 ADP + 3Pi

Again more molecules of ATP are used for phosphorylation of RuBP, which then

starts the cycle again.

CONCLUSION

For every 3 molecules of CO2 entering the cycle and combining with 3 mole of RuBP

(5C), six molecules of three carbon G3P is produced. Out of six G3P only one G3P

molecule leaves the cycle and can be used for synthesis of glucose, starch, cellulose,

sucrose or other compounds. The other 5 molecules are recycled to regenerate 5C

RuBP’s three molecules, the CO2 acceptor.



CONSUMPTION For the net synthesis of one G3P molecule, the calvin cycle consumes a total of nine

ATP’s and six NADPH + H+

PHOTORESPIRATION

In presence of light (photon), oxygen is taken up by RuBP and CO2 is evolved.

RuBP + O2 -> PGA + Phosphoglycolate ® CO2

It occurs when CO2 is deficient, Rubisco works like an oxygenase rather than

carboxylase in presence of O2, produce phosphoglycerate (phosphoglyceric acid-

PGA) and Phosphoglycolate, where phosphoglycolate rapidly breaks down to release

CO2. Alternative mechanisms of carbon fixation in hot, arid climate.

In hot temperature the concentration of CO2 begins to fall in leaves due to closing of

stomata, increase yield of photosynthesis etc. These conditions in leaves may cause a

wasteful process called photorespiration in which precious products are lost and less

energy is generated. In certain plant species alternate mode of CO2 fixation have

evolved even in very hot and arid environment.

These two photosynthetic adaptations are

1. C4 PHOTOSYNTHESIS (C4 PATHWAY)

This process occurs in C4 plants. Those which prefer calvin cycle with an alternate

mode of carbon fixation are known as C4 plants. CO2 reacts with PEP in presence of

PEP carboxylase to produce oxaloacetate, a four carbon compound which converts

into malate. Malate transfers from mesophyll cell to bundle sheath cell where it breaks

down to pyruvate and releases CO2. This CO2 is fixed in calvin cycle by Rubsico and

so the cycle continues.

E.g. Family poaceae especially sugar cane, corn.

2. CAM

Plants of hot, arid environment, open their stomata during the night and close them

during the day. Closing stomata during the day helps deserts plants to conserve water

but it also prevents CO2 from entering the leaves. During the night, when their

stomata are open, these plants take up CO2 and incorporate it into a variety of organic

acids because of lack of energy (ATPs and NADPH+ H+). This mode of carbon

fixation is called crassulacean acid metabolism (CAM). They store these organic acids

in vacuoles. During day time organic acids release CO2 for dark reaction because

light reaction can supply ATP and NADPH+ H+ on which the calvin cycle depends.

E.g. Cactus, Pinapple, Succulent plants.

CELLULAR RESPIRATION

Aerobic breakdown of glucose molecules into CO2 and water with synthesis of ATP

is called Cellular Respiration.

C6H12O6 +6O2 -> 6CO2 + 6H2O + 673 Kcal/mole



Respiration is an oxidation reduction process because the carbon of substrate, mostly

glucose is oxidized to form CO2, while the atmospheric O2 is reduced to form the

water.

There are two types of cellular respiration.

(A) AEROBIC RESPIRATION

The breakdown of sugar, in presence of oxygen [molecular O2] and release of

carbondioxide and water with sufficient amount of energy. This type of respiration is

known as Aerobic respiration, and the organisms performed this are known as

Aerobes.

(B) ANAEROBIC RESPIRATION

The break down of sugar in absence of oxygen is known as Anaerobic respiration, and

this type of respiration is performed by Anaerobs.

E.g. Yeast, some bacteria, gut parasites (e.g. tapeworm). Some species of annelids,

roots of plants growing in water logged area. Anaerobes are of two types. Those

which never need of O2 at all are Obligate anaerobes. Those which respire aerobically

but can also respire in absence of O2 are known as Facultative aerobes.

CATEGORIES OF AEROBIC RESPIRATION

The process of aerobic respiration is divided into three main categories.

1. Glycolysis

2. Kreb’s cycle

3. ETC

(1) GLYCOLYSIS

Glycolysis is the first and common step in both aerobic and anaerobic respiration. It

consists of a complex series of enzymatically catalyzed reactions in which a 6 carbon

molecule “Glucose” breaks down into 3 carbon “Pyruvic acid”. These reactions occur

in Cytoplasm and doesn’t require oxygen. Following are the different steps of

Glycolysis.

(I) PHOSPHORYLATION

Phosphorylation is the addition of phosphate groups to the sugar molecules. Glucose

is phosphorylated by a molecule of ATP to form an activated molecule, the glucose 6

phosphate. ATP is converted to ADP.

(II) ISOMERIZATION

Glucose -6-phosphate is converted to fructose -6-phosphate, an isomer of it by an

enzyme.



(III) SECOND PHOSPHORYLATION

Another molecules of ATP is invested which transfers its phosphate group to carbon

no.1 of fructose –6-phosphate, forming fructose 1,6-bisphosphate and ADP.

(IV) CLEAVAGE

The 6-carbon, fructose 1,6 bisphosphate molecule is break down into 2; three carbon

molecules, 3-phosphoglyceraldehyde PGAL and

dihydroxyacetone phosphate (DHAP). These two sugar molecules are isomers and are

interconvertible. This is the reaction from which glycolysis derives its name. DHAP is

converted to its isomer PGAL and then 2 PGAL will be converted to 2 pyruvic acid

molecules. Since at this stage 2 ATPs are used, therefore this phase is known as

Energy investment phase.

In the subsequent reactions, energy is produced therefore this half is also known as

Energy yielding phase

(V) DEHYDROGENATION (OXIDATION)

In the next step, PGAL is acted upon by an enzyme dehydrogenase along with a co-

enzyme nicotine amide adenine dinucleotide (NAD+), which convert PGAL into

phosphoglyceric acid PGA or phosphoglycerate by the loss of two hydrogen atoms

(2e- + 2H+). These H atoms are captured by NAD+. This is a redox reaction in which

PGAL oxidized by removal of electrons and NAD is reduced by the gaining of

electrons. Now phosphoglyceric acid PGA picks up phosphate group (Pi) present in

cytoplasm and becomes 1,3-bisphosphoglyceric acid (DPGA)

(VI) PHOSPHORYL TRANSFER

1,3-bisphosphoglyceric acid loses its phosphate group to ADP forming ATP and 3-

phosphoglyceric acid.

(VII) ISOMERIZATION

The PO4 group of PGA, attaches with carbon no,3 changes its position to carbon no.2

forming an isomer 1-phosphoglyceric acid.

(VIII) DEHYDRATION

A water molecule is removed from the substrate and forming phosphoenal pyruvate

(PEP)

(IX) PHOSPHORYL TRANSFER

ADP removes the high energy PO4 from PEP producing ATP and Pyruvic acid.

OVERALL REACTION of glycolysis can be summarized as Glucose + 2ADP +

2NAD+ -> 2 Pyruvic acid + 2ATP + 2NADH+ H+ + 2H2O



ENERGY YIELD

Since when PGAL is produced, the cycle is counted twice because DHAP also

converts into PGAL and enter the same cycle. 4ATP molecules are produced at

Substrate level phosphorylation because PO4 groups are transferred directly to ADP

from another molecule. 2 ATP are used in the first phase. Thus there is a net gain of 2

ATPs. 2 NADH+ H+ are produced and each gives 2 ATPs (a total of 6 ATPs).

Therefore net production of ATP during glycolysis is 8 ATPs

FATE OF PYRUVIC ACID

There are 3 major pathways by which it is further processed under anaerobic

conditions, pyruvic acid either forms, ethyl alcohol or lactic acid or produces CO2 and

H2O from kreb’s cycle under aerobic conditions.

FERMENTATION

Fermentation the alternative term for Anaerobic respiration was used by W.Pasteur

and defined as respiration in absence of oxygen (air). The production of ethyl alcohol

from glucose is alcoholic fermentation and that of lactic acid is lactic acid

fermentation.

ALCOHOL FERMENTATION

Each pyruvic acid molecule is converted to ethyl alcohol also known as Ethanol in

two steps. In the first pyruvic acid is decarboxylated to

acetaldehyde under the action of enzyme.

Pyruvic acid CH3.CO.COOH -> CH3CHO + CO2

In the next step NADH+ H+ reduces acetaldehyde to ethyl alcohol

CH3.CHO + NADH+ H+ -> CH3.CH2OH + NAD+

Ethyl alcohol is toxic, plants can never use it because it cannot be converted to

carbohydrates or breaks up in presence of O2. When accumulation is more than

tolerable limits, plants will be poisoned and subsequently they died.

LACTIC ACID FERMENTATION

When NADH+ H+ transfer its hydrogen directly to pyruvic acid, it results in

formation of lactic acid.

Pyruvic acid + NADH + H+ -> CH3.CH.OH. COOH

During extensive exercise such as fast running muscle cells of animals and man

respire anaerobically. Due to inadequate supply of O2, pyruvic acid is converted to

lactic acid. Blood circulation removes lactic acid from muscle cells. When lactic acid

accumulates inside cells, it causes Muscle futigue. This forces person to stop work,

until normal O2 levels are restored.



ECONOMIC IMPORTANCE OF FERMENTATION

1. It is the source of ethyl alcohol in wines and beers Wines are produced by

fermenting fruits like grapes, dates etc. Beers are produced by fermenting malted

cereals such as Barley.

2. Yeast is used to prepare bread from wheat.

3. Milk is converted to curd (yoghurt) by bacteria.

4. Preparation of cheese and other dairy products.

5. Production of lactic acid, propionic acid, and butanol.

6. Flavour of pickles is due to lactic and acetic acid.

7. Addition of lactic and acetic acids prevent foods from spoilage and also

give sour flavours to yoghurt and cheese.

8. Acetone is also formed as a by-product.

(2) KREB’S CYCLE

FORMATION OF ACETYL-COA

Before entering the Kreb’s cycle, each molecule of pyruvic acid undergoes oxidative

decarboxylation. During this process one of the three carbons of pyruvic acid

molecule is removed to form CO2 by enzymatic reactions. Simultaneously pyruvic

acid is oxidized and a pair of energy rich Hydrogen atoms are passed on to a H

acceptor NAD+ to form NADH+H+. The remaining 2-carbon component is called

acetyle which combines with coenzyme A to form an activated two carbon compound

called acetyle CoA. “Acetyle CoA connects Kreb’s cycle with glycolysis.” For each

molecule of glucose that enters glycoilysis, two molecules of acetyle CoA produced,

which enter in a cyclic series of enzymatically catalyzed reactions known as Kreb’s

Cycle, which occurs in Mitochondria.

Pyruvic acid (3C) + CoA + NAD+ -> Acetyle CoA + CO2 + NADH+H+

SERIES OF REACTIONS IN KREB’S CYCLE

Sir Hans Kreb was working over these cyclical series of reactions therefore the cycle

was given the name as Kreb’s cycle. The first molecule formed during the cycle is

citric acid, so it is also called as “Citric Acid cycle.” This cycle is a multi step process

and the steps are given below:

1. FORMATION OF CITRIC ACID

In this first step of the Kreb’s cycle, bond between acetyl and CoA is broken by the

addition of water molecule. The acetyl (2C) reacts with 4 carbon compound (oxalo

acetic) acid to form 6-carbon compound, citric acid, and the CoA is set free. This

citric acid possess 3 carboxyl groups, therefore the cycle is also recommended as

Tricarboxylic Acid Cycle (TCA cycle).

2. ISOMERIZATION



A molecule of water is removed and another added back so that cirtic acid is

isomerized to isocitric acid through an intermediate, Cis-aconitic acid.

3.FIRST OXIDATIVE DECARBOXYLATION

First time the sugar molecules are oxidized, therefore it is also called first oxidation of

the cycle. Isocitric acid is oxidized yielding a pair of electrons (2H+) that reduces a

molecule of NAD+ to NADH+H+. The reduced sugar molecule is decarboxylated

with the removal of CO2. It now converts into a

5 carbon compound α-Ketoglutaric acid (αKG).

4. SECOND OXIDATIVE DECARBOXYLATION

αKG is oxidatively decarboxylated. A CO2 molecule is lost. The remaining 4-C

compound is oxidized by transfer of a pair of electrons (2H+) reducing NAD+ to

NADH+H+. This 4-C compound accepts CoA forming succinyl CoA.

5. SUBSTRATE LEVEL PHOSPHORYLATION

Bond between succinyl and CoA is broken. CoA is replaced by PO4 group, which is

then transferred to Guanosine diphosphate (GDP) to form Guanosine Triphosphate

(GTP). GTP then transfers its phosphate group to ADP, forming ATP and with

addition of 1 water molecule, succinic acid is formed.

6. THIRD OXIDATION

With loss of two electrons (2H+)succinic acid is oxidized to fumaric acid and FAD+

is reduced to FADH2.

7. HYDRATION

One water molecule is added to fumaric acid to convert it to Malic acid.

8. FOURTH OXIDATION AND REGENERATION OF OXALO-ACETIC ACID

Oxidation of malic acid leads to the production of 1 more NADH+H+ and oxaloacetic

acid is regenerated.

ENERGY YIELD

Glucose molecule breaks down into 2 pyruvic acid molecules and each will enter the

Kreb’s cycle.

For each pyruvic acid molecule, 3CO2 molecules are produced, four NADH+H+ are

produced and 1 FADH2.

Pyruvic Acid + 3H2O + 4NAD+ + FAD+ -> 3CO2 + 4NADH+H+ + 1FADH2

Four calculation of energy (ATPs) we will multiply the products with 2 as 2 acetyle

CoA enters the Kreb’s cycle.



Pyruvic Acid to Acetyl CoA…………..1NADH2 -> 3ATP x 2 = 6 ATP

Kreb’s Cycle………………………………..3NADH+H+ -> 9ATP x 2 = 18 ATP

………………………………………………1FADH2 -> 2ATP x 2 = 4 ATP

………………………………………….Substrate Level Phosphorylation -> 1ATP x 2

= 2ATP

Total………………………………. = 30 ATP

OVERALL ENERGY YIELD OF AEROBIC RESPIRATION

Glycolysis…………………………8ATP

Pyruvic Acid to Acetyl CoA…………..6ATP

Kreb’s Cycle……………………….24 ATP

Total……………………………..38 ATP

But actually 2 ATPs are utilizing in transporting cytoplasmic NADH+H+ to

Mitochondria, which are produced during Glycolysis, so overall energy yield is only

36 ATPs.

3. ELECTRON TRANSPORT CHAIN/ ETC OR ET SYSTEM

The last of all steps is ETC. It consists of a series of electron acceptors which are

located in the cristae of mitochondria. In respiration there are 6 steps at which

hydrogen atoms are released (one in glycolysis, 5 in Kreb’s cycle). A pair of hydrogen

atoms are dissociated into a pair of electrons and a pair of protons.

2H -> 2H+ + 2e

These electrons are accepted by Nicotinamide adenine dinucleotide (NAD) and Flavin

Adenine Dinucleotide (FAD) from where they are passed along a chain of electron

carriers such as cytochrome b, cytochrome c; cytochrome a, cytochrome a3.While

passing from one carrier to another, these cytochromes are alternatively reduced and

oxidized. During this, the energy released is used in the formation of ATP (adenosine

triphosphate) from ADP and Pi. The final electron acceptor is atmospheric oxygen,

which also picks up protons, and form the water molecule. The formation of ATP in

mitochondria is called Oxidative Phosphorylation.

From every NAD, 3ATPs and from 1 FADH2, 2 ATPs are produced.

biology notes for class first year

Science

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