biology updated

7/28/2019 Biology Updated

1/25

1

Phagocytosis Simple Diffusion Osmosis: the diffusion of water

The pseupodia are also used for feeding.

Amoeba sp. engulfs food by phagocytosis.

Amoeba sp. is a holozoic organisms which

feed on microscopic organisms such asbacteria.

The presence of food causesAmoeba

sp.to advance by extending its pseupodia.

The pseupodia encloses the food which is

then packaged in food vacoule.

The food vacoule fuses with lysosome and

the food is digested by hydrolitic enzyme

called lysozyme.

The resulting nutrients are absorbed into

the cytoplasm.

Net movement of molecules or ions from

a region of higher concentration to a

region of lower concentration.

Going down concentration gradient untilan equilibrium is achieved.

The particles are distibuted equally

throughout the system.

The concentration gradient provides

energy to move the molecules into and

out of the cells.

Net movement of freely moving water

from a region of lower solute

concentration to a region of higher solute

concentration through a semi-permeablemembrane.//

Net movement of water from region

higher water concentration to a region of

lower water concentration.//

Net movement of water from hypotonic

region to hypertonic region.

Facilitated Diffusion Active Transport Animal and plant cells in an isotonic solution

For water soluble molecules//molecules

which are not soluble in lipids (ions,nucleic acid, amino acids and glucose)

Carrier Protein

The carrier protein function by

binding to the molecules to pass

through the plasma membrane.

The molecules move to the carrier

protein which is specific for the

molecules.

Molecules bind with the carrier

protein at the active site.

Carrier protein changes its shape and

pass the molecules through the

plasma membrane.

Movement of molecules or ions against

the concentration gradient across theplasma membranes.

Requires both carrier proteins and

expenditure of energy.

Energy from ATP (adenosine

triphosphate) that is generated during

respiration in the mitochondria.

Has active sites which bind to the ATP

molecules. The carrier protein changes shape when

the phosphate group from the ATP

molecule binds to it

Then the solute is moved across the

plasma membrane.

Solution in which the solute concentration

is equal to that of the cytoplasmic fluid. Water diffuse in and out of the cells at

equal rate.

No net movement of water.

Cells retain its normal shape.

Bright Minds 016-6412016 Thuran

Bright Minds


2/25

2

Hypotonic solution Hypertonic solution Preservation of fish and vegetables

Concentration of solute outside a cell is lower

than concentration of solute inside cell.

Animal cells Is said to be hypotonic solution.

Cell placed in hypotonic solution.

Net movement of water into the cells via

osmosis.

Cell swells up.

When extremely hypotonic, cells will

eventually burst

Cannot withstand the osmotic pressure

because of thin plasma membrane.

E.g : red blood cells (haemolysis)

Plant cells

Do not burst

Rigid cell wall.

Water diffuse into vacoule of cell viaosmosis.

Cell swells up and becomes turgid

Tugor pressure in plant.

Supporting the plant.

The concentration of solute in the solution is

higher than the concentration of solutes within

the cell.

Animal cells

Net movement of water from inside to

the outside of the cell.

Cells shrink//shrivel, internal pressure

decrease.

Red blood cells immersed in hypertonic

solution , the cell shrink and the plasma

membrane crinkles up. Cell undergone crenation.

Plant cells

Water diffuse out via osmosis.

Vacoule and cytoplasm shrink and plasma

membrane pulls away from the cell wall.

This process called plasmolysis.

Cell becomes flaccid.

Fish

Fish is covered by salt solution which is

hypertonic to body fluid/cell/tissue.

More water diffuses out from tissues intosalt solution via osmosis.

Fish becomes hydrated.

Prevents bacterial growth in fish tissues.

Bacteria cells are also

plasmolysed//crenated.

Prevent decay/last longer.

Vegetables

Vegetables are immersed in vinegar which

is acidic//has low pH.

Vinegar diffuses into vegetables tissues.

Vegetables tissues becomes acidic//has

low pH.

Prevents bacterial growth in tissues.

Preventing decay//last longer.


Bright Minds


3/25

3

Differences between facilitated diffusion and active transport

Facilitated diffusion

But

Active transport

D1

E1

Down the concentration gradient

Molecules moves from higher concentration to lowerconcentration

Against the concentration gradient

Molecules moves from lower concentration tohigher concentration

D2

E2

Molecules move in both direction across the plasma

membrane

Molecules can move through pore protein or/and carrier

protein

Molecules move in one direction across the plasma

membrane

Molecules move through carrier protein

D3

E3

No ATP/energy used

Molecule can move through pore protein without binding

ATP/energy is used

Energy needed for binding/bind with active site

D4 Molecules need carrier protein and pore protein to helpthe movement

Need carrier protein only to help movement

D5 Could achieve equilibrium Will not achieve equilibrium/result in accumulation

D6 Not depended in cellular respiration Depend on cellular respiration/energy

Similarities between facilitated diffusion and

active transport

The Importance of water General characteristics of enzymes

Both (ways of transportation)need carrier

protein.

To bind with

molecules/ion/substrate/examples

Both transport specific molecules only.

Because the carrier protein have specific

site to certain molecules.

Both processes occur in living cell.

Because carrier protein need/can change

shape to allow substances to move across.

Water is a polar molecule and act as a

solvent.

Transport medium in the blood,

lymphatic, excretory and digestive

systems and in the vascular tissues of

plant.

As a medium for biochemiocal reaction.

Helps in lubricant. Regulates body temperature.

Alter or speed up the rates of chemical

reactions

Remain unchanged at the end of reaction.

Do not destroyed by reactions they

catalysed.

Have specific sites called active site to

bind with specific substrates.

Needed in small quantities.

Reaction are reversible

Can be slowed down or stopped by

inhibitors. E.g: lead and mercury

Require helper molecules, called

cofactors.

Inorganic cofactor : ferum, copper

Organic cofactor: water soluble vitamins,

B vitamins .


Bright Minds


4/25

4

Extracellular enzyme Lock and key hypothesis Effects of temperature on enzyme activity

Extracellular enzyme is produced in a cell,

then packed and secreted from the cell.

It catalyses its reaction outside the cell.

An example is amylase.

The instruction for making the

extracellular enzyme is transcribed from

the deoxyribonucleic acid

(DNA) to ribonucleic acid (RNA) in the

nucleus.

The RNA then leaves the nucleus through

the nuclear pore and attaches itself to the ribosome

located on the endoplasmic reticulum.

When the synthesis of the enzymes is

completed it is encapsulated in a

transport vesicle which fuses with the

golgi body.

In the golgi body, the enzyme is further

modified before being packed in asecretory vesicle.

The secretory vesicle transports the

enzyme to the plasma membrane, where

it fuses with it and the enzyme is released

outside the cell.

The substrate molecule fits into the active

site of the enzyme molecule.

The substrate is the key that fits into the

enzyme lock.

Various types of bonds such as hydrogen

and ionic bonds hold the substrate

in the active site forming the enzyme-

substrate complex.

Once the complex is formed, the enzyme

changes the substrate to its product.

The product leaves the active site. The enzyme is not altered by the reaction

and it can be reused.

At low temperature, reaction takes place

slowly.

As temperature increases, movement of

substrate increase.

Increase their chances of colliding with

each other and with the active site of the

enzymes.

At optimum temperature, the reaction is

at maximum rate.

Beyond the optimum temperature, rate of

reaction will not increase. Bonds that hold enzyme molecules begin

to break.

Actives sites destroyed.

Enzyme denatured.

Prophase Metaphase Anaphase

Chromosomes in the nucleus condense.

Chromosomes appear shorter and thicker.

Consist of sister chromatid joined at the

centromere.

Spindle fibres begin to form.

Centrioles migrate at opposite poles.

At the end, nucleolus disappears and the

nuclear membrane disintegrates.

Chromosomes align at the metaphase

plate//equatorial plate//middle of the

cell.

Mitotic spindle are fully formed.

Two sister chromatids are still attached to

one another at the centromere.

Ends when the centromere divides.

Two sister chromatids separate at the

centromere.

Sister chromatids pulled apart at opposite

poles.

Chromatids are referred to as daughter

chromosomes.


Bright Minds


5/25


6/25

6

Disadvantages of cloning Meiosis I Meiosis II Long-term side effects are not yet known.

May undergo natural mutations. Disrupt

the natural equilibrium of an ecosystem.

Clones do not show any genetic

variations.

Has the same level of resistance towards

certain disease.

Certain transgenic crops contain genes

that are resistant to herbicides.

These genes may be transferred to weeds

through viruses. These weeds would then

become resistant to herbicides.

Cloned animals has shorter lifespan.

1. During prophase I, homologous

chromosomes pair up (synapsis) and

crossing over between non sister

chromatids occurs.

2. During Metaphase I, homologous

chromosomes align at the metaphase

plate (equator, middle) of the cell.

3.

During Anaphase I, homologous

chromosomes separates and move to

opposite poles. Sister chromatids are still

attached together and move as a unit.

4. At the end of Telophase I, two haploid

daughter cells are formed. Each daughter

cell has only one of each type of

chromosomes, either the paternal or

maternal chromosomes.

1. During Prophase II, synapsis of

homologous chromosomes and crossing

over between non-sister chromatids do

not take place.

2. During Metaphase II, chromosomes

consisting of two sister chromatids align

at the metaphase plate (equator/middle)

of cell.

3. During Anaphase II, sister chromatids

separate, becoming daughter

chromosomes that move to opposite

poles.

4. At the end of Telophase II, four haploid

daughter cells are formed. Each daughter

cell has the same number of

chromosomes as the haploid cell

produced in Meiosis I, but each has only

one of the sister chromatids.


Bright Minds


7/25

7

Digestion in mouth Digestion in stomach Digestion in small intestine

Secretion of saliva by three pairs of

salivary glands

Saliva contains the enzyme salivary

amylase

Begins the hydrolysis of starch to maltose.

Starch + water maltose

An additional digestive process occurs

further along the alimentary canal to

convert maltose to glucose.

pH is maintained at 6.5-7.5

Epithelial lining of the stomach contains

gastric glands.

These glands secrete gastric juice.

Consists of mucus, HCL and enzymepepsin and renin.

HCL make the pH around 2.0.

High acidity destroy bacteria.

Acidity stop the activity of salivary

amylase enzyme.

Protein + water polypeptides

Renin coagulate milk by converting the

soluble milk protein, caseinogen into

soluble caesin.

Stomach contents become a semi-fluid

called chyme.

Chyme gradually enter the duodenum.

Duodenum received chyme from stomach

and secretion from the gall bladder and

pancreas.

Starch, protein and lipids are digested.

Bile which produced by the liver and

stored in the gall bladder enter the

duodenum via the bile duct.

Bile helps neutralise the acidic chyme and

optimise the pH for enzyme action in

duodenum.

Bile salts imulsify lipids, breaking them

down into tiny droplets.

Providing high TSA for digestion.

Pancreas secrete pancreatic juice into

duodenum via pancreatic duct.

Pancreatic juice contains pancreatic

amylase, trypsin and lipase.

Pancreatic amylase complete the

digestion of starch to maltose. Trypsin digests polypeptides into

peptides.

Lipase complete the digestion of lipid into

fatty acid and glycerol.

Glands in the ileum (small intestine)

secrete intestinal juice which contain

digestive enzyme needed to complete the

digestion of peptides and disaccharides.

Peptides digested by erepsin into amino

acids.

Maltose digested by maltase into glucose.

Disaccharides digested by its own enzyme

into monosaccharides and glucose.

Salivary amylase

pepsin


Bright Minds


8/25

8

Digestion of cellulose by ruminant Digestion of cellulose by rodent Digestion

Partially chewed food is passed to the

rumen (largest compartment of the

stomach).

Cellulose is broken down by cellulaseproduced by bacteria.

Part of the breakdown products are

absobed by bacteria, the rest by the host.

Food enters the reticulum.

Cellulose undergoes further hydrolysis.

The content of the reticulum, called the

cud, is then regurgitated bit by bit into the

mouth to be thoroughly chewed. Helps soften and break down cellulose,

making it more accessible to further

microbial action.

The cud is reswallowed and moved to the

omasum.

Here, the large particles of food are

broken down into smaller pieces by

peristalsis.

Water is removed from the cud.

Food particles moved into obamasum, the

true stomach of the ruminant. (e.g : cow).

Gastric juice complete the digestion of

protein and other food substances.

The food then passes through the small

intestine to be digested and absorbed inthe normal way.

Caecum and appendix are enlarged to

store the cellulose-digesting bacteria.

The breakdown products pass through the

alimentary canal twice. The faeces in the first batch are usually

produced at night.

Faeces are then eaten again. To absorb

the products of bacterial breakdown.

The second batch of the faeces are harder

and drier.

Allows rodent (give example) to recover

the nutrients initially lost with the faeces.

Protein

- In stomach, pepsin breakdown

protein into polypeptides.

-

HCL being secreted to provide acidicmedium for the digestion to occur.

- In duodenum, trypsin breakdown

polypeptides into peptides.

- In small intestine, arepsin break dwon

peptides into amino acids.

Fats

-

Bile salts breaking up fats into smallfat droplets in the duodenum.

- In duodenum/small intestine, lipase

breaks lipids into fatty acids and

glycerol.

Carbohydrates

- In mouth, salivary amylase hydrolyse

starch into maltose.

- In duodenum, pancreatic amylase

hydrolyse starch into maltose.

- In small intestine, maltase hydrolyse

maltose into glucose.


Bright Minds


9/25

9

Absorption of digested food Assimilation of digested food Formation faeces

Absorption of digested food occur in the

ileum.

Glucose/amino acids initially diffuse into

blood capillaries. The remaining of the glucose/amino acids

actively transport into blood capillaries.

All blood capillaries converge into hepatic

portal vein, which lead to the liver (and

transport to all parts o fthe body).

Glycerol and fatty acids diffuse to the

epithelial cell which lining the ileum) and

combine to form fat droplets. Fatty acids and glycerol then enter the

lacteal (lymphatic system).

Return back to the blood stream at left

subclavian vein.

Explain the assimilation of glucose and amino acid

in body cells.

Glucose is oxidised to produce energy,carbon dioxide and water by cellular

respiration.

Amino acid is used to synthesis

protoplasm (the component of cell). By

this way new cells will be synthesised

causing growth.

Amino acid also can be used to synthesis

enzyme, hormone or antibody.

Faeces which contain dead cells that are

shed from intestinal linings, toxic

substances and bile pigments enter the

colon by action of peristalsis. In colon, more water is absorbed. The

undigested food residues harden to

become faeces.

Faeces contain undigestible residues that

remain after the process of digestion and

absorption of nutrients that take place in

the small intestine.


Bright Minds


10/25

10

Photosynthesis mechanism Photosynthesis mechanism Uses of enzyme (Chapter 4)

The formation of starch in plants is by the

process ofphotosynthesis which occurs in

chloroplasts.

The two stages in photosynthesis are thelight and dark reactions.

Light reaction:

P3:Takes place in grana.

P4: Chlorophyll captures light energy

which excites the electrons of chlorophyll

molecules to higher energy levels.

P5: In the excited state, the electrons can

leave the chlorophyll molecules. P6: Light energy is also used to split water

molecules into hydrogen ion (H+) and

hydroxyl ions (OH-) (Photolysis of water).

P7: The hydrogen ions then combine with

the electrons released by chlorophyll to

form hydrogen atoms.

P8: The energy from the excited electrons

is used to form energy-rich molecules of

adenosine triphosphate /ATP.

P9: Hydroxyl ion loses an electron to forma hydroxyl group. This electron is then

received by chlorophyll.

P10: The hydroxyl groups then combine to

form water and gaseous oxygen.

Dark Reaction:

P11: Take place in stroma.

P12: Do not require light energy.

P13: The hydrogen atoms are used to fixcarbon dioxide in a series of reactions

catalysed by photosynthetic enzymes

P14: and caused the reduction of carbon

dioxide into glucose.

P15: The glucose monomers then undergo

condensation to form starch which is

temporarily stored as starch grains in the

chloroplasts.

Enzymes are used as biological

detergents.

Protease degrades coagulated proteins

into soluble short-chain peptides. Lipase degrades fat or oil stains into

soluble fatty acid and glycerol.

Amylase degrades starch into soluble

shorter-chain polysaccharides and sugars.

Enzymes are used in the baking industry.

Protease is used in the breakdown of

proteins in flour for the production ofbiscuits.

Amylase is used in the breakdown of

some starch to glucose in flour for making

white bread, buns and rolls.

Enzymes are used in the medical field.

Trypsin is used to remove blood clots

and to clean wounds. Various other enzymes are used in

biosensors.

Enzymes are used in industries because:

They are effective.

They are cheap and easy to use.

They can be re-used, thus only small

amounts are needed.

They don't require high temperature to

work, thus this reduces fuel costs.


Bright Minds


11/25

11

Aerobic respiration Anaerobic respiration in human muscle Anaerobic respiration in yeast

Continuous supply of oxygen.

Glucose molecules are oxidised by

oxygen.

Complete breakdown of glucose in thepresence of oxygen.

A large amount of energy released.

Carbon dioxide and water are produced as

waste products.

Most of the nergy released is used to

synthesise adenosine triphosphate (ATP)

from adenosine diphosphate (ADP) and

inorganic phosphate. ATP acts as instant energy source.

ATP consists of phosphate bonds which

can be easily broken down to release

energy.

ATP ADP + phosphate + energy

During a vigorous exercise (running), the

breathing rate is increased.

This is to supply more oxygen to the

muscles for rapid muscular contraction. However, the supply of oxygen to muscles

is still insufficient.

and the muscles have to carry out

anaerobic respiration to release energy.

The glucose is converted into lactic acid,

with only a limited amount of energy

being produced.

An oxygen debt builds up in the body,when no oxygen use in energy production.

High level of lactic acid in the muscles

cause them to ache.

After running, the athlete breathes more

rapidly and deeply than normal for

twenty minutes.

There is recovery period after 10 minutes

until it reaches 20 minutes when oxygen is

paid back during aerobic respiration.

About 1/6 lactic acid is oxidized to carbon

dioxide, water and energy.

Yeast normally respires aerobically.

Under anaerobic condition, yeast carry

out anaerobic respiration.

Produces ethanol.

Process known as fermentation.

Catalysed by the enzyme zymase.

- Ethanol produced can be used in

making wine and beer.

- In bread making, the carbon dioxide

released during fermentation of yeast

causes the dough to rise.

Similarities between the sturucture of digestive and digestion process of ruminants and rodents

S1

Both alimentary canal contains bacteria/protozoa

P1 To secrete extracellular enzyme//to digest

P2 To digest cellulose into glucose

S2 Both have large surface area

P1 To increase rate of diffusion //hydrolysed food

Energy released


Bright Minds


12/25


13/25

13

Transport of O2 and CO2 in human body

(continuation)

Explain how energy flows through the food chain

and how it is lost to the environment.

Colonisation and succession in mangrove

swamps

Oxyhaemoglobin dissociates to release

oxygen.

Carbon dioxide released by repairingcells can be transported by dissolve

carbon dioxide in the blood plasma.

Bind to the haemoglobin.

As carbaminohaemoglobin.

In form of bicarbonate ions.

Carbon dioxide is expelled with water

vapour from the lung.

Energy flows through the food chain in one

direction .

In the food chain, the plant is the producer,

the rat is the primary consumer, the snake is

the secondary consumer and the eagle is the

tertiary consumer.

In the food chain, the plant is the producer,

the earthworm is the primary consumer, the

bird is the secondary consumer and the

snake/ eagle is the tertiary consumer. Each

level of food chain is called a trophic level.

Energy is transferred from one trophic level

to another trophic level.

When energy is transferred from one trophiclevel to another level as much as 90% of the

chemical energy in the food consumed by

primary consumer is used for its metabolic

activities and lost as heat.

Only 10% of the energy in an organism is

passed on to the organism at the next trophic

level.

The pioneer species of a mangrove

swamp are the Sonneratia sp. and

Avicennia sp. The presence of this species gradually

changes the physical environment of

the habitat.The extensive root systems

of these plants trap and collect

sediments, including organic matter

from decaying plant parts.

As time passes, the soil becomes more

compact and firm. This conditionfavours the growth ofRhizophora sp.

Gradually the Rhizophora sp. replaces

the pioneer species.

The prop root system of the Rhizophora

sp. traps silt and mud, creating a firmer

soil structure over time.

The ground becomes higher. As a result,

the soil is drier because it is less

submerged by sea water.

The condition now becomes more

suitable for the Bruguiera sp., which

replaces the Rhizophora sp.

The buttress root system of the

Bruguiera sp. forms loops which extend

from the soil to trap more silt and mud. As more sediments are deposited, the

shore extends further to the sea. The

old shore is now further away from the

sea and is like terresterial ground.

Over time, terrestrial plants

like nipah palm and Pandanus sp. begin

to replace the Bruguiera sp.


Bright Minds


14/25

14

Green house effects Explain briefly why humans carry out the activity

as shown in diagram above

Explain the impacts of the activity shown above

on the environment

Green house effect.

Ultra violet(uv) from solar radiation isabsorbed by the earth and some of them

is reflected back to the atmosphere in the

form of heat/infra red.

Heat or infrared radiation cannot be

reflected back to the atmosphere.

Because it is trapped by green house

gases such as CO2, nitrogen dioxide and

methane. Heat/infrared warmed the surface of

earth.

Earth temperature increases.

The human population grows rapidly. The

demands for food and housing areas have

increased.

Vast areas of forest are cleared for

agricultural and commercial purposes.

Urbanization and industrialization have

caused more forests to be cleared for

road construction and housing areas.

Deforestation is also caused by the

demands for timber and fuel wood.

Deforestation causes soil erosion ,

landslides, flash floods and globalwarming.

Causes the soil to become loose and less

stable.

Without the protection of green plants,

the soil is exposed to the forces of wind

and rain.

The top layer of soil is washed away

gradually by the rainwater. This is known as soil erosion.

Soil erosion causes the depletion of

minerals from the soil, therefore the soil

becomes infertile and unsuitable for

agriculture.

Landslides may happen on steep hillsides

during heavy rain.

It is because rainwater flows quickly and

causes the top layer of the soil to

crumble.

Rivers and drains are silted and the flow

of water is blocked.

Therefore, water flows inland and this

causes flash floods in the lower areas

during rainy seasons.


Bright Minds


15/25

15

Human blood vessels Circulatory system in fish and human Blood clotting

Arteries

- carries blood away from heart

- transport blood quickly, at high pressure

- muscle of tissue enables the artery to

constrict and dilate

- walls of arteries are strong and elastic,

have small lumen

Capillaries

- thin walled blood vessels

- allow rapid gaseous exchange via diffusion

- nutrients, wastes and hormones are also

exchanged across here- one cell thick

Veins

- blood returns from capillaries to heart

through veins

- blood flows in low pressure

- have large lumens and valves (prevent

back flow)

Similarities

- both have closed circulation

- both have a heart

Differences

Fish Human

Has single circulation Has double circulation

Heart divides into 2

chambers

Heart is divided into 4

chambers

Septum is absent Septum is present

Deoxygenated bloodflows from heart to

gills

Deoxygenated bloodflows from heart to

lungs

Oxygenated blood

flows from gills to

body cells

Oxygenated blood

flows from lungs to

heart

- clumped platelets, damaged cells, clotting

factors form activators (thromboplastins)

- activators together with calcium ions and

vitamin K, converts prothrombin to

thrombin

- thrombin catalyses the conversion of

soluble protein fibrinogen into insoluble

fibrin.

- fibrin is a fibrous protein which combines

to form a mesh of long threads over the

wounds, trapping red blood cells and

sealing the wound.- blood clot hardens when exposed to air

forming scab

Difference between blood and lymph Type of immunity Phagocytosis

- lymph has a large numbers of lymphocyte

compare to blood

- lymphocyte is produced by lymph nodes

in lymph system

- lymph has lower content of oxygen

compare to blood

- active immunity, body produces its own

antibodies in response to stimulation by

an antigen

- passive immunity, body receive an

antibodies from outside source

- the phagocyte is attracted by chemicals

produced by bacterium

- Phagocytes extend its pseudopodium

(legs) towards bacterium to engulf it.

- ingestion of bacterium forms phagosome

- phagosome combines with lysosome

-lysosome releases lysozyme into

phagosome

- bacterium inside the phagosome will be

destroyed by lysozyme

- phagocyte releases the digested products

from cell


Bright Minds


16/25

16

Lymph formed - brought back into the blood

circulatory system.

Respiratorygases Active immunity Passive immunity

- when blood flows from arteries into

capillaries, there is higher hydrostatic

pressure at artial end of capillaries

- high pressure causes some plasma to pass

through capillary walls into intercellular

spaces

- interstitial fluid fills the spaces between

cells and constantly bathes the cells- 90% of interstitial fluid diffuses back into

blood capillary

- 10% of interstitial fluid goes into the lymph

capillaries and known as lymph

- lymph capillaries unite forming larger

lymphatic vessels

- from lymphatic vessels, lymph eventually

passes into thoracic duct

- hence lymph drains back into blood

Transportation in respiratory gas.

- oxygen enters alveoli during inhalation

- gaseous exchange occurred at alveoli

(oxygen diffused into blood capillaries

while carbon dioxide diffused out)

- the diffusion of these gases caused by

different of partial pressure of both

gaseous- partial pressure of oxygen in alveoli is

higher than partial pressure of oxygen in

blood capillaries

- oxygen diffused in cytoplasm of red blood

cell

- oxygen combines with haemoglobin

forming oxyhaemoglobin

-oxyhaemoglobin then sent to all parts of

body

- heart pumped the oxygenated blood to all

body cells

- oxygen diffused from blood capillaries to

cell because partial pressure of oxygen in

blood capillaries is higher than in cell

- carbon dioxide diffuse from cell to blood

capillaries because partial pressure of

carbon dioxide in cell is higher than in

blood capillaries

- deoxygenated blood going back to heart

by vena cava and to lungs by pulmonary

artery

Active immunity

- obtained by vaccination (artificially

acquired)

- vaccine contains dead/weakened

bacteria/pathogen/virus

- white blood cells stimulated to produce

antibodies against pathogen

-also obtained when an individual hasrecovered from certain diseases(naturally

acquired)

- a ready made supply of antibody will give

immunity towards the disease

Passive immunity

- obtained by injecting

antibodies/antiserum (artificially

acquired)

- no antigen is put into body, so body does

not produce its own antibodies

- obtained by a baby when antibodies from

mothers blood plasma diffuse into foetus

through placenta (naturally acquired)


Bright Minds


17/25

17

Movement of water froom root toleaves Movement of water from root toleaves Effect of no lignin formation on the function of

tissue xylem

Movement of water from root to leaves aided by

root pressure, capillary action and transpirational

pull.

Root pressure

cell sap of root hair(usually) hypertonic to

surrounding soil solution

water diffuses into root by osmosis

cell cap becomes more dilute compared

to neighbouring cell

water moves to these adjacent cells whichbecome more diluted themselves, so

osmosis continues across the cortex

(at the same time) ions from soil are

actively secreted into xylem vessels and

causes osmotic pressure to increase

Water flows continuously into xylem and

create a pressure(root pressure)

Root pressure gives an initial upwardforce to water and mineral ions in xylem

Capillary action

water moves up through xylem in stems

by capillarity

capillary action is due to combined force

of cohesion(water molecules have

attraction for each other) and

adhesion(water molecules are attracted

to the side of vessels)

water molecule form a continuous water

column in xylem vessel (due to cohesion

and adhesion) the cohesion of water prevent the water

column in xylem breaking apart

the adhesion of water prevents gravity

from pulling the water down the column

Transpirational pull

the lost of water from mesophyll cells

during transpiration is replaces by waterwhich flows in from xylem vessels in

leaves

this creates a tension/suction force in

water column because water has cohesive

properties called transpiration pull

the transpiration pull draws water from

xylem in the leaves/stem/roots

the continuous flow of water through

plant is known as transpiration stream

lignin is important to make tissue xylem

strong

- without lignin, tissue xylem will collapse

- therefore, it cannot form a continuous

hollow tube

- to allow water to flow upwards

continuously

lignin makes the tissue become

impermeable

- materials cannot pass in xylem cells

- causes the tissue to become hollow

- allows continuous flow of water

-

(choose one of the * and the explanations below)


Bright Minds


18/25

18

light intensity and stomata and cells effect the

rate of water loss

Adaptation of the muscle which enables it to

contracts

Movement takes place involves muscles,

tendons, bones, ligaments and joints

F1- from 0500 to 0170(time/hours), rate

of water loss increases

E1- light intensity increases

E2- stimulates photosynthesis in guard

cells

E3- this makes energy available for

potassium to move into guard cells by

active transport

E4- guard cells become

hypertonic(compared to cell sap) of

epidermal cells E5- water molecules from epidermal cells

diffuse into guard cells by osmosis

E6- causing guard cells to bend outwards

E7- stoma opens (allows water to escape)

F2- from 0170 to 0300(time/hours) rate of

water loss decreases

E8- lisght intensity decreases/rate of

photosynthesis decreases

E9- guard cells become flaccid and bend

inwards

E10- stoma closes, prevents water from

escaping

Notes: (F1 + any 5Es) + (F2 + 3Es)

- the skeletal muscle consist of bundles of

muscle fibres and a large supply of nerves

and blood vessels

- a muscle fibre is made up of bundles of

smaller units called myofibrils

- each myofibril is made up of 2 types of

protein filaments: the actin and the

myosin which interact and cause muscle

contractions

- the muscles nerve endings control its

contractions

Muscle

- quadriceps femoris contract while biceps

femoris muscles relax (leg straightened)

- biceps femoris contract while quadriceps

femoris relax (leg bent)

- calf muscles contract to lift up the heels

- feet push downwards and backwards

- repeated contraction and relaxation of

muscle result in running movement

Ligaments

-

it connects 2 bones together- give support and strength to joints for

movement

- strong and elastic

Joints

- a hinge joint allow the movement of leg to

swing back and forth

Tendon

-connect muscles to bones

- strong and non elastic

- force is transferred to bones through

tendons

Bones

- femur/ thigh bone is long, heavy and

strong

- provide support to body weight


Bright Minds


19/25

19

Adaptation of plant which enable it to float Skeletal system of earthworm and fish adapted

for its movement

Adaptive features which helps in birds and fish

locomotion

- have fine aerenchyma wall tissues (plants

become more lighter)

- have air spaces/air sacs (becomes more

easy to float)

- have big and swell stem/petiole (increase

the air to help plant floating)

- have fine and many roots (trap gas

bubbles)

Movements in earthworm

- earthworm has hydrostatic skeleton

- moves by changing hydrostatic pressure

of fluid in its segment

- each segment of the body has its own set

of muscles

o an outer layer of circular muscles

running around the body causes the

worm to become long and thin when

they contract

o

an inner layer of longitudinal musclescauses the worm to get short and

thick when they contract

- as the circular muscles contract, the

longitudinal muscles will relax

simultaneously in antagonistic action

- causes the hydrostatic pressure to be

transferred from anterior part to posterior

part causing the worm to move forward

Movements in fish

- fish has an endoskeleton

- it provides place for attachment of

muscles

- when the left myotome contracts, right

myotome will relax in antagonistic action

-causes the vertebral column to curvetoward the left

- the fish also has fins with different

functions for locomotion

Bird

- aerofoil wing to generate the upward lift

- a pair of antagonistic muscle (pectorolis

major and minor) pulled down and up the

wings

- single organ (one testes/kidney)//small

skull to reduce weight

- streamlined body shape reduce air

resistance

- waterproof feather avoid increase in

body weight during rainingFish

- streamed lined body reduce water

resistance

- myotome muscle are W/V shaped which

act antagonistically

- air sac maintain buoyancy in water

- fins

o

dorsal and ventral fin prevent/helps in yawing and

rolling

o tail fin provides thrust and

controls direction

o pelvin and pectoral fin act as

brakes/to slow down


Bright Minds


20/25

20

Support is achieved in submerged and floating

plants

Osteoporosis and osteoarthritis happen -

prevented

Important to have healthy musculoskeletal

system - ways maintaining a healthy

musculoskeletal

Submerged plants

- posses air sacs within the leaves and the

stem to help the plant to stay upright in

water

- water buoyancy provides support

- have very few woody tissue/vascular

tissue

- thin/narrow/flexible leaves provide little

resistance to water flow

Floating plants- stem have plenty of air sacs

- aerenchyma tissues helps to stay afloat in

water

- do not have woody tissues

- natural water buoyancy to help them float

- have broad leaves that are firm but

flexible to resist being torned by wave

action

Osteoporosis

- a disease in which bone mass is reduced

and the boned become porous and lighter

- occurse most often in old people, partially

women who have gone menopause

- bodies of postmenopausal women do not

produce sex hormone, oestrogen

- causes more bone minerals to be lost than

deposited

-

as a results, bones become soft and brittle- can be prevented by

o doing weight-bearing exercise,

strengthen the muscles and bones

o taking diet rich in calcium,

phosphorus and vitamin D

o takin in vitamin C, increase bone

mass

o

refraining from smokingOsteoarthritis

- Osteoarthritis is part of ageing process

due to wear and tear of cartilage between

bones at certain joints

- Patient has painful, swollen stiff knees

which restrict daily activities (walking,

climbing)

-If treatment fails to relieve the pain, asurgeon can replace the damaged joints

with artificial ones made of plastic or

metal

The musculoskeleton system where bones,

muscles, ligaments and tendons work together

like a machine to bring about movement

- musculoskeleton helps to support our

body

- if any part of system injured, we will

experience discomfort, pain and loss of

mobility

-

it also affect othe organs and physiologicalprocesses in body (respiration/digestion)


Bright Minds

B i h Mi d 016 6412016 Th


21/25

21

Important to have healthy musculoskeletal

system - ways maintaining a healthy

musculoskeletal

Osteoarthritis and arthritis gout occur - effect of

the diseases

Support system in woody plants differs from that

of non-woody plants

Ways to maintain

- having balanced diet. Take diet rich in

proteins, vitamins A, C n D together with

minerals (calcium,phosphate n iron) for

building strong bones. Drinking

fluoridated water will also harden the

bones

- adopt a good posture while standing,

sitting, walking and while performing

certain tasks to ensure that our body isalways supported. This is important

because bad posture will put undue

pressure on our muscles and spine and

this will in turn affect the functions of our

internal organs (lungs, heart and stomach)

- wear proper attire for daily activities.

Wear loose and comfortable clothes. Tight

clothes restrict our movement. Womanwearing high heels tilt the body forwards.

To counteract this, the woman bends her

knees and throws her trunk forwards,

causing the spine to curve even more

- taking precautions during vigorous

activities

- practice correct and safe techniques when

exercisingto prevent serious injuries tothe musculosketonn system

Muscular dystrophy

- muscle destroying disorder

-weakness/weaking of muscles

- mostly in male

- affect the heart muscle heart attack

- results in poor balance/wobbling/poor

movement

Osteoporosis

- condition characterized by lost of normal

density of bone- resulting in fragile bone

- bone fracture

- no symptom before any bone fracture

- consequences fracture of

vertebrae//reduction of in height over

time//stooped posture

Non-woody plants (herbaceous plants)

- (support in herbaceous plants is) provided

by the turgidity of

parenchyma/collenchyma cells

- (when there is enough warm in the

ground) the cells take in water by osmosis

and become turgid

- The turgor pressure of fluids in the

vacuoles pushes the cell contents/plasma

membrane against the cell wall- Creating support for its tem/roots/leaves

- The thin thickening die cell walls with

cellulose/collenchyma cells gives support

to herbaceous plants


Bright Minds

Bright Minds 016 6412016 Thuran


22/25

22

Support system in woody plants differs from that

of non-woody plants

Synapse The event as a nerve impulse is

transmitted across a synapse

Knee jerk

Woody plants

- woody plants have specialized

tissues/sclerenchyma tissues/xylem

vessels.tracheids to give them support

- these tissues have cellulose walls which

have deposits of lignin for added strength

- sclerenchyma cells have very thick walls

(do not allow water to pass through)

- (these cells are dead cells) their function is

to provide support

-

Xylem vessels have thick walls of ligninwhich are deposited during the plants

secondary growth

- The lignified xylem vessels form the

woody tissues of the stem

- This makes the plant stronger and also

provides support for the plant

- Tracheids are also dead cells with thick

walls and very small diameters- They are found with xylem vessels and

together they support the plants

Synapse is a narrow gap between an axon

terminal and a dendrite of another

adjacent neuron. A chemical is used by

neuron to transmit an impulse across a

synapse. The chemical is called

neurotransmitter

The transmission of information across a

synapse involves the conversion of

electrical signal into chemical signal in the

form of neurotransmitter Neurotransmitter is produced in vesicles

in a swollen part of the axon terminal

called synaptic knob

Synaptic knob contains abundant

mitochondrion to generate energy for the

transmission

When an impulse arrived at the synaptic

knob, the vesicles release theneurotransmitters into the synapse

The neurotransmitters molecules diffuse

across the synapse to the dendrite of

another neurons

The dendrite of another neurons is

stimulated to trigger a new impulse which

travel down a long neuron

- the knee jerk action involves two types of

neurons named afferent and efferent

neurons

-when a hammer hits a tendon that

connect to quadriceps muscle in the thigh

to a bone in the lower leg

- as the hammer strike, the force stretches

the quadriceps muscle and stimulates the

stretch receptors in the muscles,

triggering nerve impulse

-

afferent neurons transmit the informationto the quadriceps muscle and the muscle

contracts swing the leg forward

- if the patient is able to swing the leg

forward, it indicates that the patients

nerve system is still functioning

- if there is no response, it shows that the

patients nervous system fails to function

properly


Bright Minds



23/25

23

When the hand touches a hot object Roles of cerebellum and medulla oblongata -

reflex action when finger being stung by a bee

Glomerular filtrate formed

- the heat on the object stimulates the

nerve endings (receptors) in skin

- impulses are triggered

-impulses travel along the sensory/afferent

neuron to spinal cord

- in spinal cord, the impulses are

transmitted first across a synapse to the

interneurone and then across another

synapse to the motor/efferent neurone

At synapse- when an impulse reach a presynaptic

membrane, it triggers the synaptic

vesicles to release neutrotransmitter into

the synaptic cleft

- the neurotransmitter diffuse across the

synaptic cleft

- and bind to receptors which are attached

to the postsynaptic membrane- the binding of the neurotransmitter to the

receptors leads to the generation of a

new impulse

- impulses leave the spinal cord along the

motor/efferent neurone to the effector

- the effector is the biceps muscle which

then contracts. This brings about a sudden

withdrawal of the hand

Cerebellum

- coordination of movement

- controls of balance/posture

Medulla oblongata

- controls/increase breathing

- controls/increase heart rate

- controls blood pressure/sweating

Reflex action

- receptors in the skin of the finger detects

pain

-

nerve impulse is generated in painreceptor

- electrical impulses are sent via the

afferent(sensory) neurone to spinal cord

- impulses are transferred to the

interneurone in the spinal cord

- interneurone sents impulses to the

efferent neurone

-efferent neurone sents impulses tobiceps/muscle

- biceps/muscle contract (triceps relax)

causing the arm to bend

- when blood enters the glomerulus,

ultrafiltration takes place

- because blood from the aorta reaches the

nephron/glomerulus at high pressure

- and due to the different artiole and

efferent arteriole

- the high pressure forces fluid through the

filtration membrane into capsular space

forming glomerular filtrate


Bright Minds



24/25

24

Structure and the role of nephron - formation of

urine

Formation of urine Consequences of kidney failure

Structure and the role of nephron

- nephron is the functional unit of a kidney

- a nephron consist of 3 major parts

(glomerulus, and its associated vessels)

- the Bowmans capsule

- a long narrow tube called the renal

tubule, which made up of proximal

convoluted tubule, loop of Henle and

distal convoluted tubule

- the distal convoluted tubules of several

nephrons join to a common collecting

duct

- the loop oh Henle is a long hairpin-shaped

region of the nephron that descends into

the medulla and then returns to the

cortex

- ultrafiltration, reabsoprtion and secretion

- blood is under relatively high pressure

when it reaches the nephron

-high blood pressure in glomerulus, forces

fluid to filter through the filtration

membrane into the lumen of Bowmans

capsule

- forming glomerular filtrate

- contains water, glucose, amino acids,

mineral salts and other small molecules

- the glomerular filtrate will flow into

proximal convoluted tubule

- selective reabsoption occurs

- by active and passive transport

- forming relatively high solute

concentration in the peritubular

capillaries

- thus large volume of water is reabsorbed

into the blood by osmosis- increase the concentration of urea in the

convoluted tubule

- glomerular filtrate then flow into loop of

henle and distal convoluted tubule

- more water and minerals being

reabsorbed back into the blood

- take place in the distal convoluted tubule

-urea/toxins/ammonia/ect being secretedby passive diffusion and active transport

from blood capillary into distal convoluted

tubule

- filtrate reaches the collecting duct (now

called urine). flows down the ureter, the

bladder and urethra and is finally excreted

- if both kidneys stop functioning, the blood

osmotic pressure and blood volume

cannot be maintained

-the built up of toxic wastes in the body

can result in life-threatening conditions

- they have to undergo haemodialysis

- another treatment for impaired kidney

functions is the transplant of a healthy

kidney from a donor to the patient


Bright Minds


25/25

biology updated

Documents