SPM Biology Form 4 – Terminology and Concepts: Movement of Substances Across the Plasma Membrane (Part 1)

Uniqueness of Plasma Membrane (also known as cell membrane):

it is a semi-permeable cell membrane it allows water and certain substances

to move in and out of the cell.

2. Importance of Plasma Membrane:

- cells obtain nutrients and gases cells excrete metabolic wastes cells can maintain pH for enzyme

activity cells can maintain ionic concentration

of the cells for enzyme activity control the types and the amount of

substances allow useful substance

(hormones/enzymes) to secrete from cells

protect cells a boundary between the inside and

outside of cell.

3. Structure of the basic unit of plasma membrane

Phospholipid molecule:‘Head’ – hydrophilic: a polar phosphate molecule (philic~loves water / attracted to water)‘Tail’ – hydrophobic: two non-polar fatty acids (phobic~hates water / repelled to water)

Formation:Hydrophilic heads pointing outwardsHydrophobic tails pointing inwards(Bilayer phospolipid)

Fluid Mosaic Model (Protein embedded in the bilayer)

Carrier protein

carrier for some molecules (glucose, amino acids, proteins and nucleic acids)

controls the movement of ions and particles (Na+, Ca2+ and K+)

Glycoprotein

Glycolipid

combination of lipids and polysaccharides

4. Permeability

Permeable (allow to pass through)

small non-polar molecules (vitamins A, D, E, K, fatty acids, glycerol and steroids)

Impermeable (not allow to pass through but with help of carrier protein and cellular energy, it is allow to pass through)

large polar molecules (glucose, amino acids, mucleic acids and polysaccharides)

charged ions (H+, Na+, K+, Cl- and Ca2+)

Substances that are allowed to move in the cell:

CO2

O2

excess H2O waste: nitrogenous

Substances that are allowed to move out of the cell:

CO2

O2

amino acids ionic salts glucose

SPM Biology Form 4 – Terminology and Concepts: Movement of Substances Across the Plasma Membrane (Part 2)

Materials must be able to move through the plasma membrane in order for the cell cytoplasma to interact with the external environment. Therefore, the movement of soluble substances can occur in several mechanisms:

A. Process of Passive Transport B. Process of Active Transport

A. Passive Transport

i) Simple Diffusion

not selective: lipid-soluble molecules, gases and water.

not control by cell. movement of the molecules from a

region of higher concentration to a region of lower concentration.

Factors affecting the rate of diffusion are temperature, size of molecules/ions, diffusion gradient, surface area and diffusion medium.

example: diffusion of oxygen and carbon dioxide at the alveolus.

ii) Osmosis:

only water molecules. not control by cell. movement of water from a region of

higher concentration to one of lower concentration and often occurs across a semipermeable membrane.

strong sucrose solution = less water molecule = low water potential.

weak sucrose solution = more water molecule = high water potential.

example: absorption of water by root hairs.

iii) Facilitated Diffusion:

very specific: glucose, nucleic aicds, amino acids, protein and mineral ions.

control by cell. transport of molecules (only certain

molecules) across the outer membrane of living cell by a process of carrier protein (hydrophilic group) / channel protein (Ions: Na+, Ca2+, K+) within the cell membrane.

normally take place from a region with higher concentration of molecules to a region of lower concentration.

example: absorption of digested food in the villus.

B. Process of Active Transport

very specific: minerals ions and amino acids.

control by cell. This process needs carrier proteins and

energy (due to against concentration gradient) from a region of lower concentration to a region of higher concentration).

Cell must expend energy that derived from ATP (adenosine triphosphate)

example: human nerve cells (sodium ions are constantly transport out of the cell) / ions intake by root hairs of a plant.

SPM Form 4 – Terminology and Concepts: Movement of Substances Across the Plasma Membrane (Part 3 – Final)

Type of Solution

1. Hypotonic2. Isotonic3. Hypertonic

1) Hypotonic

Solute concentration in the external solution is lesser than solute concentration inside the cell.

Water concentration outside the cell is higher than the water concentration inside the cell.

2) Isotonic

Solute concentration in the external solution is equal to the solute concentration inside the cell.

Water concentration inside and outside of the cell is the same.

3) Hypertonic

Solute concentration in the external solution is greater than solute concentration inside the cell.

Water concentration outside the cell is lower than the water concentration inside the cell.

Types of solutions:

Type of Solution

Hypotonic Isotonic Hypertonic

Animal Cell

The cell inflates due to the water molecules enter the cell. Eventually it bursts (thin plama membrane). Example: red blood cell in distilled water.

No change in the size of cell. Net movement of water is zero. Example: red blood cell in 0.85% sucrose solution.

The cell shrinks and becomes soft and dehydrated due to the water molecule leave the cell. Example: red blood cell in 5% sodium chloride solution.

Plant Cell

The cell expands and becomes firm / turgid due

No change in the size of cell. Net

The cell becomes flaccid

to the water molecules enter the cell. The rigid cellulose cell wall expands slightly and prevents cell from bursting. Example: strip of potato in distilled water.

movement of water is zero. Example: strip of potato in 5% sucrose solution.

(plasmolysis occurs), vacuole and cytoplasma shrink due to the water molecules leave the cell. Example: strip of potato in 30% sucrose solution.

Application

1. Food is soaked in a concentrated salt solution to prevent bacteria and fungus to survive.

2. Chemical fertiliser (dissolved ions) increases solute concentration (decrease water molecules) in soil. Therefore, water leaves from the cell sap of the plant which result the plant wither.

SPM Form 4 – Terminology and Concepts: Cell Structure and Cell Organisation (Part III)

Organelles – (little organ) tiny structures inside a cell that perform specific functions for a cell. Example: mitochondria, lysosome and chloroplast.

Mitochondria

Animal: High density at sperm cells (at middle piece to provide sufficient energy for motive power), flight muscle cells (bird / avian), liver cells, meristematic / meristemic cells (involve with cell division), kidney cells, heart muscle cells, brain cells.

Chloroplasts

Plant: High density at palisade mesophyll (leaf: below upper epidermis). It functions to trap sunlight to synthesise sugar during photosynthesis.

The Uniqueness of The Cell

A cell is unique:

1. Specialisation 2. Division of labour3. Coordination and integration

Example of specialisation of cells :

Animal – smooth muscle cell, neuron (nerve cell), white blood cell, red blood cell (erythrocyte), cheek cell (lining epithelial cell), sperm, ovum cell (the biggest cell in human)

Plant – palisade mesophyll cell, xylem, phloem, guard cell

SPM Form 4 – Terminology and Concepts: Cell Structure and Cell Organisation (Part IV)

Cell Organisation

Unicellular – A single cell performs all the basic life process. Example: Amoeba sp., Paramecium sp., Chlamydomonas, Bacteria and Euglena.

Multicellular – An organism consists of more than one cell. Each group of cell specialized to carry our life processes. Example: Homo sapien (human), animals and plants. It has five levels of organisation

1. Cells: basic units of structure and function.Example: Red blood cells and xylem vessel cells.

2. Tissues: made up of cells with similar in structure and function.Example: Epithelial tissues and vascular tissues.

3. Organs: made up of tissues that perform a specific function.Example: Heart and flower.

4. System: two of more organs that perform a specific function.Example: Digestive system and root system.

5. Organisms: whole living thing that carry out all the basic life processes.Example: Human and durian tree.

Cell Organisation (Unicellular) in Amoeba sp. (lives in freshwater ponds) and Paramecium sp. (lives in soil and moist area)

1. Cell structure

Amoeba sp.: plasma membrane, food vacuole, contractile vacuole,

pseudopodium, nucleus, ectoplasma, endoplasm.

Paramecium sp.: food vacuole, posterior contractile vacuole, cytostome, gullet, oral groove, cilia, macronucleus, micronucleus, anterior contractile vacuole.

2. Locomotion

Amoeba sp.: Pseudopodium (false foot) helps it to move forward slowly and it is known as amoeboid movement.

Paramecium sp.: Hair-like cilia to beat against water. It beats its cilia backwards diagonally (swim forward) and it rotates on its axis. It beats its cilia forward (swim backwards).

3. Feeding

Amoeba sp.: Omnivore. Eat bacteria, plant cells, algae and other microscopic organisms.

1. Entrapment – extend pseudopodium.2. Engulfment – engulf tiny food

(phagocytosis) with its pseudopodia.3. Digestion – food enclosed in food

vacuole4. Absorption – enzyme digests the

bacteria5. Egesting – expel indigestible material.

Paramecium sp.: Eat bacteria, organic material and other microscopic organisms.

1. Sweeping – movement of cilia. Food moves along the oral groove into the gullet and cytostome.

2. Digestion – food vacuole circulates round the cell.

3. Elimination – undigested food is eliminated at the anal pore.

4. Reproduction

Amoeba sp.: two types of reproduction.

1. Binary Fission – nucleus divides (favourable condition) and then follows by division of cytoplasm. Two daughter cells are formed (mitotic division).

2. Spore Formation – spores form (bad condition) and germinate into new amoeba under favourable condition.

Paramecium sp.: two types of reproduction.

1. Binary Fission – micronucleus undergoes mitosis (favourable condition). Macronucleus begins to elongation and form two. Cell content divide and two daughter cells are formed.

2. Conjugation (Sexual reproduction) – two same species parent paramecia exchange genetic material of their micronuclei. Each parent divides and forms four daughter cells.

5. Osmoregulation

Amoeba sp.: water moves into the cell by osmosis and prevention of bursting, it has a contractile vacuole.

Paramecium sp.: water moves into the cell by osmosis and prevention of bursting, it has two contractile vacuoles.

6. Respiration

Amoeba sp. and Paramecium sp. (both): exchange gases throughout the whole cell membrane

7. Excretion

Amoeba sp. and Paramecium sp. (both): waste products are ammonia and carbon dioxide by diffusion. Solid waste

in paramecium is expelled through its anal pore.

Cell Organisation (Multicellular) in Human

1. Cells: Epithelial cells, muscle cells, white blood cells, red blood cells, sperm, nerve cells.

2. Tissues: Epithelial tissue, smooth muscle tissue, connective tissue, skeletal tissue, nerve tissue.

3. Organs: Stomach, heart, kidney, lung, liver.

4. Systems: Circulatory system, respiratory system, digestive system, excretory system, muscular system, lymphatic system, integumentary system, skeletal system, nervous system, endocrine system, reproductive system.

5. Organisms: Human.

Cell Organisation in Plant

1. Cells: Parenchyma cells, collenchyma cells, sclerenchyma cells, epidermal cells.

2. Tissues: Epidermal tissue, meristem tissue, vascular tissue.

3. Organs: Leaf organ, flower organ, stem organ, root organ.

4. Systems: Shoot system, root system.5. Organisms: Plant.

SPM Form 4 – Terminology and Concepts: Cell Structure and Cell Organisation

Cell Structure and Function

Comparison between Animal Cell (AC) and Plant Cell (PC)

9. Golgi apparatus / Golgi body: AC and PC

bound sacs processes , packages and transport

molecules synthesised in the cell

forms lysosomes transports and stores lipids synthesis of carbohydrate from

hormone changes protein into glycoprotein excretes waste products out of the cell

10. Cytoplasm: AC and PC

aqueous solution (except nucleus) stores water, enzymes, nutrient, salts

and dissolved gases provided support, shape and protects

the cell organelles medium for metabolic reactions provides substances

11. Lysosome: AC

sac-like organelle with one membrane digest proteins, lipids and

carbohydrates removes undigested materials releases enzymes to digest external

materials

12. Centriole: AC

are paired cylindrical organelles nine tubes with three tubules each produces spindle during cell division

(mitosis and meiosis) migrate to the opposite poles of the cell

(during cell division – will be discussed in Chapter 5 Cell Division)

13. Vacuole: AC (temporary / lower class species) and PC

small cavity in the cytoplasm bound by a single membrane filled with cell sap storage of food (protein, oil and water) some vacuoles remove metabolic waste functions as cell expansion Amoeba: food vacuoles (phagocytosis)

Paramecium: contractile vacuoles (expel water)

14. Cell Wall: PC

rigid and tough cellulose layer surrounding the plasma membrane (cell membrane)

protects and supports the cell maintains the shape prevents the cell from busting

(excessive intake of water) allows substances to move freely

through the cell wall

15. Chloroplast: PC

disc / lens-shaped organelle have two membranes: inner and outer

membrane contains chlorophyll in the grana to trap

sunlight energy carry out photosynthesis in the

chlorophyll storage of food and pigments

Keys:

AC and PC = similarities AC or PC = differences (Carbohydrates

storage: AC = Glycogen / PC = Starch)

SPM Form 4 – Terminology and Concepts: Cell Structure and Cell Organisation

Cell Structure and Function

Comparison between Animal Cell (AC) and Plant Cell (PC)

1. Mitochondrion (pl: Mitochondria): AC and PC

spherical / rod-shaped organelles two membranes : Inner membrane –

form cristae & Outer membrane – regular and smooth

an energy source site of cellular aerobic respiration produces ATP (adenosine triphosphate)

2. Nucleus (pl: Nuclei): AC and PC

contains the genetic material regulates and controls the activities of

the cell an organelle bounded by double (2)

layers of nuclear membrane with pores and selectively permeable

responsible for all cellular structure, chemical functions, growth and reproduction

separates the genetic materials (chromatin) from cytoplasm

3. Nucleolus: AC and PC

spherical structure within the nucleus consists of DNA (deoxyribonucleic acid)

and RNA (ribonucleic acid) and proteins visible when the cell is not dividing synthesis RNA which is needed to make

ribosomes

4. Nucleoplasm: AC and PC

fluid contained within the nucleus highly viscous solid made up of the chromatin and the

nucleolus

5. Chromosomes

thread-like structures (consists of genetic material)

appears as chromatin spread throughout the nucleus in the form of tiny granules

chromatin condenses into chromosomes (during cell division)

carry genetic information in its DNA

6. Ribosomes: Ac and PC

small dot-like organelles protein synthesis consist of RNA (ribonucleic acids) smallest cellular organelles attached on the surface of ER and occur

freely in cytoplasm

7. Endoplasmic reticulum (ER): AC and PC

connected to the nuclear membrane synthesises proteins, steroids and lipids collects , stores and distributes protein,

steroids and lipids exists as rough ER and smooth ER Rough ER: covered with ribosomes, flat

sealed sac which continued from the nuclear membrane, transports protein, and have a large surface area for chemical reactions.

Smooth ER: does not have ribosomes, transports lipids and presents in large amounts of cells.

8. Plasma membrane: AC and PC

cell membrane thin membrane surround the cytoplasm

of a cell selectively permeable / semi permeable a protective and selective outer barrier consists of phospholipids and protein

molecules

SPM Biology Form 4 Notes – Terminology and Concepts: Introduction to Biology

Biology and Its Importance

Biology - earlier study as Botany (study of plant) and Zoology (study of animals) but now Modern Biology has many fields such as Genetic Engineering, Biotechnology and Bacteriology.

Biology - the scientific study of life.

It’s Importance:

1. Education.2. Knowledge3. Control4. Research5. Economy6. Quality of life7. Diseases8. Problem solving9. Careers

Scientific Investigation

The following are steps involved in a scientific investigation:

1. Define the problem2. Form a hypothesis3. Plan the investigation4. Control the variables5. Collect the data6. Analyse the data7. Interpret the data8. Make a conclusion9. Write a report

Berry Berry Teacher would like to recommend young berries to follow these rules in writing their report:

1. Aim / Objective2. Statement of problem (must be in the

form of question)3. Hypothesis4. Variables (Manipulated, Responding

and Fixed)5. Materials6. Apparatus7. Technique8. Procedure / Method of the experiment9. Results / Record of data10. Discussion / Presentation of data11. Conclusion (accept of not accept the

hypothesis)

SPM Biology 2009 – Tips and Predictions for Papers 4551/1 , 4551/2 and 4551/3

BIT Paper 1

All the questions are evenly distributed, so there are not chances for you to skip any chapter. So work hard on these important chapters!

Berry Important Topics:

Chapter 2 – Cell Structure and Cell Organisation

Chapter 3 – Movement of Substances across the Plasma Membrane

Chapter 6 – Nutrition Chapter 10 – Transport Chapter 12 – Coordination and

Response Chapter 13 – Reproduction and Growth Chapter 14 – Inheritance

All of these topic that I have mentioned are Berry Berry Important Topic, so do not ever think to skip these BIT!

Not so important topic (with only an average 2 questions every year):

Chapter 5 – Cell Division Chapter 7 – Respiration Chapter 11 – Support and Locomotion Chapter 12 – Variation

Totally not important (zero questions each year)

Chapter 1 – Introduction to Biology

BIT Paper 2 ( Structure )

Berry Important Topics:

Chapter 4 – Chemical Composition of the Cell

Chapter 5 – Cell Division Chapter 8 – Dynamic Ecosystem Chapter 10 – Transportation Chapter 14 – Inheritance

Not so important topic:

Chapter 2 – Cell Structure and Cell Organisation

Chapter 9 – Endanger Ecosystem Chapter 11 – Support and Locomotion Chapter 12 – Coordination and

Response

BIT Paper 2 ( Essay )

Chapter 7 – Respiration Chapter 9 – Endangered Ecosystem Chapter 12 – Coordination and

Response Chapter 14* – Inheritance Chapter 15* – Variation

*This year super berry hot topic!

BIT Paper 3

Chapter 3 – Movement of Substances across the Plasma Membrane

Chapter 6 – Nutrition Chapter 8 – Dynamic Ecosystem Chapter 15 – Variation