NOTA BIOLOGY SEM1 2021_2022

KOLEJ MATRIKULASI NEGERI SEMBILAN

SB015

BIOLOGY 1

NOTES

SEMESTER I

2021/2022

1.0 MOLECULES OF
LIFE

1.0 MOLECULES OF
LIFE

COURSE LEARNING OUTCOMES

1.1 WATER

a) State the structure and properties of water molecules. (CLO1)
b) Relate the properties of water and its importance: universal solvent, low viscosity, high specific heat

capacity, high latent heat of vaporization, high surface tension and maximum density at 4°C. (CLO2)

1.2 CARBOHYDRATES

a) State the classes of carbohydrates such as monosaccharide, disaccharides and polysaccharides. (CLO1)
b) Illustrate the formation and breakdown of maltose. (CLO 2)
c) Compare the structures and functions of starch, glycogen and cellulose. (CLO 3)

1.3 LIPIDS

a) State the types of lipid: triglycerides (fat and oil), phospholipids and steroids. (CLO 1)
b) Describe structure of fatty acids and glycerol. (CLO 3)
c) Explain the formation and breakdown of triglycerides. (CLO 3)

1.4 PROTEINS

a) Describe the basic structure of amino acids. (CLO 3)
b) State how amino acids are grouped. (CLO 1)
c) Describe primary (1°), secondary (2°), tertiary (3°) and quaternary (4°) levels of proteins and the types of

bonds involved. (CLO 3)
d) Describe the effect of pH and temperature on the structure of protein. (CLO 3)
e) Explain the formation and breakdown of dipeptide. (CLO 3)
f) Classify proteins according to structure and composition. (CLO 1)

1.5 DNA AND RNA MOLECULES

a) State the structures of a nucleotide as the basic composition of nucleic acids (deoxyribonucleic acid, DNA
and ribonucleic acid, RNA). (CLO 1)

b) Illustrate the structure of DNA based on the Watson and Crick Model. (CLO 2)
c) Compare DNA and RNA. (CLO 3)

1.1 WATER

COURSE LEARNING OUTCOMES
a) State the structure and properties of water molecules.

1. STRUCTURE OF WATER

• The chemical formula for water is H2O (consist of 2

hydrogen atoms and one oxygen atom)

• Two hydrogen atoms join to the oxygen atom by single

covalent bonds, produced shaped like wide V.

• The angle between two hydrogen atoms is 104.5° (see Figure 1.1.1: A water molecule

Figure 1.1.1)

• Oxygen is more electronegative than hydrogen, so the

electrons of the covalent bonds spend more time closer

to oxygen than to hydrogen; these are polar covalent

bonds.

• This unequal sharing of electrons and water’s wide V-

like shape make it water a polar molecule, meaning

that its overall charge is unevenly distributed.

• Thus, oxygen of the molecule has partial negative

charges (δ-) and the hydrogens have partial positive
charges (δ+).

• Hydrogen bond : A chemical bond that formed when

the δ+ charge hydrogen atom of a polar covalent bond
in one molecule is attracted to δ– charge oxygen atom

of a polar covalent bond in another molecule, causing Figure 1.1.2: Water molecule hydrogen bonded
them to stick together. with 4 other water molecules.

COU•RSDEuLe EtoApRoNlaIrNityG, eOaUchTwCaOteMr EmSolecule able to hydrogen
b) Relbaotendtehde pwriothpeforutiresotohfewr awtaetrear nmdoiltesciumlepso. r(tsaeneceF:igpuorlear molecules, low viscosity, high specific heat capacity,

high1.1la.2te) nt heat of vaporization, high surface tension and maximum density at 4°C (CLO 2).

PROPERTIES OF WATER

Universal solvent

Low viscosity

Properties of water High specific heat capacity
High latent heat of vaporization

High surface tension

Maximum density at 4°C

1. WATER IS A UNIVERSAL SOLVENT

● Water is a universal solvent because they are polar molecules.
● Thus, water molecules have the ability to form hydrogen bonds with other molecules.
● By forming hydrogen bonds, it will attract the opposite charges of polar molecules, ions or solute.

The importance of the property:

● Give them as powerful universal solvent for:
o Other polar substances (e.g: sugar which have slightly charged hydroxyl group -OH),
o Ionic compounds (e.g: sodium chloride, NaCl): Na+ & Cl- ions are exposed to the solvent.
o Organic molecules with ionized groups (such as the carboxyl group –COO- & amino group –NH3+)

● For example: Water is a powerful solvent for ionic compounds (when salt or NaCl, is placed in water)

.o The oxygen atoms have a partially negative charged

which are attracted to the positively charged sodium

ions, Na+

o The hydrogen atoms have a partially positive

charged which are attracted to the negatively

charged chloride ions, Cl-

o Thus, water molecules neutralized electrostatic

interactions between the oppositely charged ions.

o As a result, water molecules surround the individual

Na+ & Cl-, separating them from one another.

o The sphere of water molecules around each

dissolved ions known as a hydration shell.

▪ (see figure 1.1.3)
o Ionic bonds between NaCl molecules are become

weaker. Figure 1.1.3: Salt dissolved in water

o This will cause these ions to separate.
o Thus, salt is dissolved.

2. WATER HAS LOW VISCOSITY Figure 1.1.4: Synovial fluid cushion the movement of joint

• Water has low viscosity due to the weak hydrogen bonds

between water molecules are constantly break and
reform.

• Causing the water molecules slide easily over each other

and flow with less friction.

The importance of the property:

• This property make water a good lubricant to

reduce friction on cell surface. For example,
synovial fluid contain water which act as lubricant to
ease/cushion the movement of joint. (see figure
1.1.4).

• Low viscosity also makes water act as medium of

transportation in living organisms. For example,
blood plasma contain water and make it flow easily in
the circulatory system through narrow vessels.

3. WATER HAS HIGH SPECIFIC HEAT CAPACITY

• Water has high specific heat capacity because large amount of heat that must be absorbed for 1 g of water to change

its temperature by 1 ̊C.

• Water needs to absorb high amount of heat before increase its temperature in order to break the hydrogen bond

between water molecules.

• Much of heat is used to disrupt hydrogen bonds before the water molecules can begin to move faster.

The importance of the property:

• This property able to protect water from rapid temperature changes (water temperature do not change easily).

aquatic environments like ponds & lakes very slow to change temperature when the surrounding air temperature
changes.

• This will stabilize aquatic temperature suitable for aquatic organisms to live in.
• This property also makes water act as heat buffer or heat insulation. It prevents rapid changes in body

temperature of terrestrial organism.

4. WATER HAS HIGH LATENT HEAT OF VAPORIZATION Figure 1.1.5 Sweating give the cooling effect

• Water has high latent heat of vaporization due to large amount

of heat energy absorbed to break the hydrogen bond between
water molecules, and change 1 g water from liquid to vapor.

• 580 cal needed to evaporate 1 g water at 25 C̊
• Due to hydrogen bonds that difficult to separate and vaporized.

• Prevent water from easily evaporate.

The importance of the property:

o This property of water release excess body heat

efficiently and give cooling effect.

o Body heat will be vaporized sweat gives cooling effect

because the sweat absorbs a lot of heat energy from our
bodies. (see figure 1.1.5)

o In transpiration process, the vaporization process needs a

lot of energy, cause cooling effect to the leaves & helps
prevent overheating.

5. WATER HAS HIGH SURFACE TENSION Figure 1.1.6 Water strider on water surface
Figure 1.1.7 Capillary action
• Water has high surface tension involve cohesive & adhesive

forces (mainly involve cohesive)

• Cohesion: Water molecules stick to each other by the hydrogen

bonds.

• Adhesion: Water molecules cling to the surface of another

substance

• Hydrogen bond between water molecules create large cohesive

force.

• Related to cohesion is the surface tension, a measure of how

difficult it is to stretch or break the surface of liquid.

• At the interface between water & air, there is an arrangement

of water molecules, which hydrogen bonded to one another &
to the water below it.

The importance of the property:

o This property of water allows some aquatic

organisms to move on the water surface. (see
figure 1.1.6)

o It also involves in capillary action of cohesive &

adhesive forces helps in transportation of water
& dissolved mineral ions in plants.

o Cohesive and adhesive properties
of water molecules form an unbroken
continuous water column in the xylem.

o Water adheres strongly to xylem surfaces & can be

drawn upwards, without breaking the water column.
(see figure 1.1.7)

6. WATER HAS MAXIMUM DENSITY AT 4°C Figure 1.1.8 Water molecules in liquid state and ice
state
• As temperature falls from 4 C̊ to 0 C̊ .
• Water begins to freeze & solidify when its molecules are no

longer moving vigorously, thus, not enough to break their
hydrogen bonds.

• As water solidifies, water molecule expands and lock in

crystalline lattice; condition where each water molecule
hydrogen bonded to maximum 4 other water molecules. (see
figure 1.1.8)

• The ice formed is less dense than the cold water around it.
• It is because the hydrogen bonds in ice create space & the

water molecules relatively far apart.

• Making them to have 10% fewer molecules than an equal

volume of liquid water at 40C. This gives ice to float in water.

The importance of property: Figure 1.1.9 Ice float on water surface for survival of
aquatic organism
o Ice floats on the water surface for survival

aquatic organisms.

▪ The floating layer act as insulator layer.
▪ To insulates the water below,

preventing it from freezing

▪ in order to allow aquatic life to survive

under the frozen surface.

1.2 CARBOHYDRATES

● Composed of Carbon (C), Hydrogen (H) and Oxygen (O) atoms.
● Importance of carbohydrates:

- As energy source,
- energy storage
- to build necessary cell components

COURSE LEARNING OUTCOMES
a) State the classes of carbohydrates such as monosaccharides, disaccharides and polysaccharides.

(CLO1)

3 Classes of carbohydrates

Monosaccharides Disaccharides Polysaccharides

MMoonnoossaacccchhaarriiddee iiss ssiimmppllee sugar A disaccharide (also Macromolecules that formed
usnuigtsar(munointsom(meorsn)owmheircsh) mwhaikcehup called a double sugar) is the from hundreds to a few
amllaokteheurpcaalrlboothyedr rcaaterbso; hcyadnrnaotet sb;e sugar formed when two thousand monosaccharides
fcuartnhneorthbyedrfuorlythzerdhinydtoroslmyzaeldlerinto monosaccharides are joined joined together by glycosidic
usnmitasl.ler units. by glycosidic linkage. linkage.

EExxaammpplleess:: GGlluuccoossee,, FFrruuccttoossee Examples: Maltose, Examples: Starch, Glycogen
aanndd GGaallaaccttoossee Sucrose and lactose and Cellulose

There are two types of glucose α – glucose

β – glucose The position of hydroxyl
group at carbon no.1 is
The position of hydroxyl below the ring plane.
group at carbon no.1 is
above the ring plane.

COURSE LEARNING OUTCOMES
b) Illustrate the formation and breakdown of maltose. (CLO 2)

1. FORMATION OF MALTOSE

● Maltose is a disaccharide formed by linking 2 molecules of α- glucose.
● Through the process of condensation/dehydration.
● 1 water molecule is removed from the joining of hydroxyl group (OH) of α- glucose, and hydrogen atom (H) from

another α- glucose.
● The 2 molecules of α- glucose are joined by α – 1, 4 glycosidic bond/linkage.
● α – 1, 4 glycosidic bond/linkage joins the number 1 carbon of one α- glucose, to the number 4 carbon of the second α-

glucose.
● The end products are 1 molecule of maltose and 1 molecule of water.

2. BREAKDOWN OF MALTOSE

● Maltose is broken down into 2 molecules of α- glucose. Maltase enzyme catalyzes the hydrolysis
● Through the process of hydrolysis. of disaccharide maltose into two simple
● 1 water molecule is added in order to break α – 1, 4 glycosidic bond/linkage. sugars of glucose. It synthesized by cells
● The hydroxyl group (OH) of the both α- glucose is reformed. of the mucous membrane lining the
● The end products are 2 molecules of α- glucose. intestinal wall.

COURSE LEARNING OUTCOMES

c) Compare the structures and functions of starch, glycogen and cellulose. (CLO 3)

Storage Starch Amylose
polysaccharides Glycogen Amylopectin
Cellulose
Polysaccharide Structural
polysaccharides

STARCH

• Function of starch is the storage polysaccharide in

plant.

• Starch is made up from repeating monomer of α-

glucose.

• Insoluble in water and thus enables to be stored in

large amount without affecting water potential of cell.

• Found in form of granules in chloroplast and other

plastids also in potato tubers, cereals and rice.

• Starch is a mixture of amylose and amylopectin.
• Amylose is linear unbranched helical chain while

amylopectin is long branched, some helical chains.

• Branches of amylopectin occur every 30 units of α-

glucose

• Amylose only consist α-1,4 glycosidic bond

between its monomer while amylopectin consists α-
1,4 glycosidic bond and branch α-1,6 glycosidic
bond.

Figure 1.2.2 Structure of amylopectin (a) polymer
chain. (b) general shape

Figure 1.2.1 Structure of amylose (a) polymer
chain. (b) general shape

GLYCOGEN Figure 1.2.3 Structure of glycogen (a) polymer chain. (b)
general shape
• Function of glycogen is a polysaccharide

storage in animal and fungi.

• Glycogen is made up from repeating monomer

of α- glucose.

• Soluble in water as they are extensively

branched.

• Glycogen are extensively branched of helix

chains that joined together by α-1,4 glycosidic
bond (at linear site) and α-1,6 glycosidic bond
(at branch site).

• Branch of glycogen occur approximately every

10 units of α-glucose.

• Found in the form of granules mainly in liver

and muscle cell.

• Breakdown of glycogen in these cells releases

glucose when the demand for energy increases.
(The extensively branched structure of
glycogen fits its function: More free ends are
available for breakdown.)

CELLULOSE

• Function of cellulose is major component

of the tough wall that enclose plant cells.

• Cellulose is made up from repeating

monomer of

• β- glucose.
• Insoluble in water.
• Long chains of 2000-3000 units of β-

glucose units which are arranged in a
straight parallel strands & cross linked by
hydrogen bonds.

• Each β-glucose is related to the next

monomer by a rotation of 180°. Making
every glucose monomer upside down with
respect to its neighbors.

• Have no branched.

• Parallel cellulose molecules are held together by hydrogen bonds between hydroxyl groups which

attached to C3 & C6 with the adjacent chains. It’s given structure of cell wall as hard/strong/rigid and
also give support/mechanical strength also give the shape to the plant cell

• Parallel cellulose molecules held together into microfibrils.

Starch Glycogen Cellulose

Monomer α- glucose α- glucose ß- glucose
α- 1,4 glycosidic bond
Types of bond (in amylose) and, α- 1,4 α- 1,4 glycosidic bond ß- 1,4 glycosidic bond
between glycosidic bond & α- 1,6 and
monomer Have hydrogen bond
glycosidic bond (in α- 1,6 glycosidic bond cross linked (between
Cross linked with amylopectin) C6 & C3 of adjacent
hydrogen bond No
No chain
Branch Helix branched chain Parallel unbranched
Amylose is linear helix with more extensively
Form unbranched chain and polymer
branched polymer
amylopectin is helix Fibers
branched chain Small granules

Granules

Solubility in water Insoluble in water Soluble in water Insoluble in water

Function Storage polysaccharide in Storage polysaccharide Major component of the
plant in animal & fungi tough wall that enclose

plant cells.

Occurrence In plant In animal and fungi In plant

1.3 LIPIDS

● Greek ~ lipos ~ fat
● Organic compounds that contain: carbon (C), hydrogen (H) & oxygen (O).

● The ratio of oxygen atoms to hydrogen atoms is much lower than the 1:2 ratio found in carbohydrates.

● Insoluble in water (hydrophobic) but soluble/dissolve in organic solvents such as acetone, ethers, benzene
& other non-polar solvents.

● The importance of lipids:
- Energy storage – twice energy content compared to carbohydrates due to long hydrocarbon chain
which contain many C – H bonds in fatty acid lipid compare to carbohydrates.
- Protection of vital organs – adipose tissue cushions the organs.
- Heat insulator - layer of fat beneath skin insulates the body.
- Transport medium for fat soluble vitamins – A, D, E, K.
- Component of cell membrane.

COURSE LEARNING OUTCOMES

a) State the types of lipid: triglycerides (fat and oil), phospholipids and steroids. (CLO 1)

3 Types of Lipid

Triglycerides (fat & oil) Phospholipids Steroids

Made up from 1 glycerol Made up from 1 glycerol, 2 Lipid with carbon skeleton
and 3 fatty acids. fatty acids and 1 phosphate that consists of four fused
group. carbon rings, with variable
Two types of fatty acid: length of side chain.
saturated fatty acid and Phospholipid molecules
unsaturated fatty acid. consist of hydrophilic head and No fatty acid.
hydrophobic tails. Functional groups attached
to the rings determine the types
of steroids

COURSE LEARNING OUTCOMES

b) Describe structure of fatty acids and glycerol. (CLO 3)

1. STRUCTURE OF FATTY ACID

● R-COOH
● Fatty acid consists of long hydrocarbon chain (R), with carboxyl group (COOH)
● Fatty acid can be classified into:

i. saturated fatty acid

ii. unsaturated fatty acid

Saturated fatty acid Unsaturated fatty acid

No double bond between carbon atoms of Have one or more double bonds between carbon
hydrocarbon chain. atoms of hydrocarbon chain,
Each carbon is saturated with hydrogen atoms. with one fewer hydrogen atom on each double-
bonded carbon / Carbon is not saturated with
Hydrocarbon chain can be closely packed together. hydrogen atoms.
It tends to give a straight chain.
Hydrocarbon chain cannot be closely packed together
due to presence of double bond between carbon
atoms.
It tends to give a bend shape & form kink structure.

Example of saturated fatty acids - Stearic acid Example of unsaturated fatty acids - Gadoleic acid

A fat made from saturated fatty acids is called A fat made from unsaturated fatty acids is called
saturated fat, mostly animal fat such as lard and unsaturated fat, fat of the plant and fishes such as
butter. olive oil and cod liver oil.
Usually solid at room temperature because the Usually liquid at room temperature because the kink
hydrocarbon chain lacks double bonds and their where the cis double bonds are located prevent the
flexibility allows the fat molecules to pack together molecules from packing together closely enough to
tightly. solidify at room temperature.

Cold-blooded animals usually have higher proportion of unsaturated fatty compared warm-blooded
animals. Cold blooded animal has body temperature that depends on the surrounding. Since
unsaturated fatty acids consist of double bond which can easily to be broken at lower temperature
compared to saturated fatty acid. Importance in maintaining fluidity of cell membrane.

2. STRUCTURE OF GLYCEROL Glycerol molecule

• Consists of a three-carbon skeleton attached by 3

hydroxyl group to the end.

• An alcohol.
• Also known as glycerin.

COURSE LEARNING OUTCOMES

c) Explain the formation and breakdown of triglycerides. (CLO 3)

1. FORMATION OF TRIGLYCERIDE

● Triglycerides formed from 1 molecule of glycerol and 3 molecules of fatty acids.
● Joined by ester linkage/bond.
● Through the condensation/ esterification reaction.
● 3 water molecules are removed from the reaction.
● Water molecules was removed from one OH at the carboxyl groups on fatty acids and one H at the hydroxyl

group on glycerol.
● The end products are 1 molecule of triglycerides and 3 molecules of water.

2. BREAKDOWN OF TRIGLYCERIDE

● Breakdown of triglyceride is called hydrolysis reaction.
● 3 water molecules will be added to break 3 ester linkages/bonds.
● The OH from water molecule react with carboxyl end of fatty acid, and H react with hydroxyl end of glycerol.
● Carboxyl group of each fatty acid is reformed.
● Hydroxyl group of glycerol is also reformed.
● The end product is 1 molecule of glycerol and 3 molecules of fatty acids

1.4 PROTEIN
S

COURSE LEARNING OUTCOMES

a) Describe the basic structure of amino acids. (CLO 3)

STRUCTURE OF AMINO ACID

• Monomer for the protein is amino acid.

• Amino acid is an organic molecule with both an amino group

and a carboxyl group. (see figure 1.4.1)

• At the center of the amino acid is an asymmetric carbon

called the alpha (α) carbon.

• Its 4 partners are an amino group (-NH2), carboxyl group (-

COOH), hydrogen atom (H) and a variable group symbolized

by R. The R group also called side chain, differs with each

amino acid. Figure 1.4.1: Basic structure of amino acid

• The R group may be a simple as hydrogen atom, or it may

be a carbon skeleton with various functional group attached.

• The physical and chemical properties of the side chain determine the unique characteristic of a particular amino

acid, thus affecting its functional role in a polypeptide.

• Amino acids are amphoteric ~ having the characteristics of an acid and a base.

• Amino acid is capable of reacting chemically either as an acid or a base because it has acidic carboxyl group

(-COOH) and basic amino group (-NH2).

COURSE LEARNING OUTCOMES

b) State how amino acids are grouped. (CLO 1)

COURSE LEARNING OUTCOMES

c) Describe primary (1°), secondary (2°), tertiary (3°) and quaternary (4°) levels of proteins and the types of bonds
involved. (CLO 3)

FOUR LEVELS OF PROTEIN STRUCTURE

Primary level of Secondary level Secondary level Tertiary level of Quaternary level
lysozyme made of α-helix is in of β-pleated protein is in of protein is in
up of a single keratin in hair, sheet is in silk enzymes, the haemoglobin
strand containing nails, horn and protein. hormones, which consist of 4
129 amino acids. antibodies,
feathers. polypeptide
myoglobin and chains.
plasma protein.

COURSE LEARNING OUTCOMES

d) Describe the effect of pH and temperature on the structure of protein. (CLO 3)

A polypeptide chain of a given amino acid sequence can be arranged into a three-dimensional (3D) shape determined by
the interactions responsible for secondary and tertiary structure.

However, protein structure also depends on the physical and chemical conditions of the protein’s environment. If the
extreme pH, salt concentration, high temperature, or other aspects of its environment are altered, the weak chemical
bonds and interactions within a protein may be destroyed, causing the protein to unravel and lose its native shape, a change
called denaturation. Because it is misshapen, the denatured protein is biologically inactive.

Protein only works best at optimum pH or optimum temperature only. If deviation occurs from optimum pH or optimum

temperature, protein may be denatured.

1. THE EFFECT OF EXTREME pH ON PROTEIN STRUCTURE

● 3-dimensional (3D) structure of protein is relatively unstable, due to the weak bonds such as hydrogen bonds,

ionic bonds that maintain the protein shape are disrupted.
● Extreme pH will disrupt these weak bonds and hydrophobic interaction, and causes the 3D shape of the protein

become unravel/unfolding and lose its native shape – protein is denatured.
● Denatured protein will lose the biological activities and not functioning.

2. THE EFFECT OF HIGH TEMPERATURE ON PROTEIN STRUCTURE

● High temperature (>40°C) can disrupt hydrogen bonds and hydrophobic interactions.
● This occurs because heat increases the kinetic energy and causes the molecules to vibrate so rapidly and

violently that the weak bonds are disrupted,
● It will cause the 3D shape of the protein become unravel/unfolding and lose its native shape – protein is

denatured.
● Denatured protein will lose the biological activities and not functioning.
● Examples:

o The white of the egg becomes opaque during cooking because the denatured proteins are insoluble
and solidify.

o Excessive high fever can be fatal because the proteins in the blood (such as enzymes, hormones,
haemoglobin and antibodies) tend to denature at very high body temperature.

o Medical supplies and instruments are sterilized by heating to denature proteins in bacteria and thus
destroy the bacteria.

COURSE LEARNING OUTCOMES

e) Explain the formation and breakdown of dipeptide. (CLO 3)

FORMATION OF DIPEPTIDE

● Dipeptide formed from combination of two amino acids.
● Joined by peptide bond.
● Through the condensation/dehydration reaction.
● Removed 1 water molecule.
● Water removes from -OH at the carboxyl group of one amino acid, and H atom at the amino group of another amino

acid.
● The end products are 1 molecule of dipeptide and 1 molecule of water.

BREAKDOWN OF DIPEPTIDE

• Breakdown of dipeptide is occurred through hydrolysis reaction.
• 1 water molecule will be added to break the peptide bond.
• The OH of water react with carboxyl end of one amino acid, and H atom of the water react with amino end of

another amino acid.

• Carboxyl group of amino acid is reformed. Fibrous protein
• Amino group of another amino acid is also reformed. Globular protein
• The end product is 2 molecules of amino acid. Simple protein
Conjugated protein
COURSE LEARNING OUTCOMES

based on structure

Classification of protein

based on composition

f) Classify proteins according to structure and composition. (CLO 1)

CLASSIFICATION OF PROTEINS

Classification of protein based on structure

Fibrous protein Globular protein

● Stable protein ● Unstable protein
● Made up from long fiber strands/ sheets
● Made up from compactly folded spherical
polypeptide. shape polypeptide
● Secondary level of structure is the most
● Tertiary and quaternary level of structure is
important functional structure of fibrous the most important functional structure of
protein globular protein
● Insoluble in water
● Generally soluble in water / form colloidal
● Static molecule solution.
● Function: For mechanical & structural
● Dynamic / non-static molecule
support to cells.
● Example: Keratin, collagen, myosin and ● Function: Involves in metabolic function as
biological agent/biocatalyst of an organism
insulin.
● Example: Enzyme, hormone and
haemoglobin

Classification of protein based on composition

Simple protein Conjugated protein

● Simple proteins, contain only amino acids. ● Protein that attached to one or more non-
protein
● Proteins could be fibrous or globular
● The protein part is tightly or loosely bound
● They possess relatively simple structural to one or more non-protein part.
organization
● The non-protein part pf these proteins is
● Example: Keratin, collagen, myosin and called prosthetic group.
insulin
● Prosthetic group is essential for biological
function of these proteins

● Conjugated proteins usually globular in
shape and soluble in water

● Most of the enzymes are conjugated
protein.

● Example: Phosphoproteins and
glycoprotein

1.5 RNA AND DNA
MOLECULES

COURSE LEARNING OUTCOMES

a) State the structure of a nucleotide as the basic composition of nucleic acids (deoxyribonucleic acid, DNA and
ribonucleic acid, RNA). (CLO 1)

STRUCTURE OF A NUCLEOTIDE Figure 1.5.1: Basic structure of nucleotide

• Nucleotide is a monomer for nucleic acids (DNA & RNA)
• It consists three components; pentose sugar, nitrogenous

bases and phosphate group. (see figure 1.5.1)

• Nitrogenous base link to pentose sugar at carbon number 1.
• While phosphate group link to pentose sugar at carbon

number 5.

• There are two types of pentose sugars. In DNA the pentose

sugar is deoxyribose sugar, while in RNA pentose sugar is
ribose sugar.

• Nitrogenous bases also can be divided into two groups. It can

be purine (double ring nitrogenous base) and pyrimidine
(single ring nitrogenous base).

• Nitrogenous base under group purine are adenine and

guanine while nitrogenous base under group pyrimidine are
cytosine, thymine and uracil. (see figure 1.5.2)

• The types of nitrogenous bases found in the DNA are

adenine, thymine, cytosine and guanine while the types of
nitrogenous bases found in the RNA are adenine, uracil,
cytosine and guanine. (see figure 1.5.3)

Figure 1.5.2: Nitrogenous bases under purines and
pyrimidines

Figure 1.5.3 (a) Deoxyribonucleotide Figure 1.5.3 (b) Ribonucleotide
(nucleotide of deoxyribonucleic acid, DNA) (nucleotide of ribonucleic acid, RNA)

COURSE LEARNING OUTCOMES

b) Illustrate the structure of DNA based on the Watson and Crick Model. (CLO 2)

DNA DOUBLE HELIX STRUCTURE – WATSON AND CRICK MODEL

• Monomer for DNA is nucleotide.
• Nucleotide consist of three

components: deoxyribose sugar,
phosphate group and nitrogenous
base.

• Nitrogenous bases for DNA are

adenine, thymine, guanine and
cytosine.

• DNA structure is double helix

means it consist of two
polynucleotide strands that coiled
into helix form.

• One full helix turn consists of 10

base pairs.

• Two strands of polynucleotide are arranged in anti-

parallel. Means in opposite direction. One strand from 5’
to 3’ end and another strand from 3’ to 5’ end.

• Each strand made up from deoxyribose sugar and

phosphate group, repeating to form sugar phosphate
backbone.

• Sugar phosphate backbone on the outside, which protect the paired nitrogenous bases inside the helix structure.
• Nucleotides are joined together by phosphodiester bond to from polynucleotide. Phosphodiester bond was

formed between 3’ hydroxyl group of deoxyribose sugar and 5’ hydroxyl group of another deoxyribose sugar with
the phosphate group.

• Two strands of polynucleotide are joined together by hydrogen bond between paired nitrogenous bases

Nitrogenous bases are complementary pairing to one another.

• One nitrogenous base from purine group is hydrogen bonded with one nitrogenous base from pyrimidine group.

Adenine (A) pairing with thymine (T) by two hydrogen bonds.
Guanine (G) pairing with cytosine (C) by three hydrogen bonds.

Chargaff's Rules of Base Pairing

Chargaff's rules state that DNA from any species of any organism should
have a 1:1 stoichiometric ratio of purine and pyrimidine bases and, more
specifically, that the amount of guanine should be equal to cytosine and
the amount of adenine should be equal to thymine.

COURSE LEARNING OUTCOMES

c) Compare DNA and RNA. (CLO 3)

COMPARISON BETWEEN DNA AND RNA

Similarities between DNA and RNA

1. Both are type of nucleic acid
2. Both are called polynucleotide / polymer
3. Both are made up from monomer called nucleotide
4. Both adjacent nucleotides are joined by phosphodiester bond

DNA RNA

Double stranded polynucleotides Single stranded polynucleotide
(consist of long chain of nucleotides) (consist of shorter chain of nucleotides)

Helix form Linear form

Deoxyribose as pentose sugar Ribose as pentose sugar
Nitrogenous bases: Adenine (A), Thymine (T), Cytosine Nitrogenous bases: Adenine (A), Uracil (U), Cytosine (C)

(C) & Guanine (G). & Guanine (G)
A pairs with T, C pairs with G. U pairs with A & C pairs with G

Found only in nucleus Manufactured in nucleus but found in cytoplasm

Only one type (DNA) Three types of RNA which is mRNA, rRNA, and tRNA

Larger molecular mass Smaller molecular mass

Stable molecule Less stable molecule

DNA is self-replicating RNA is synthesized from DNA as needed basis

Ratio of A and T is the same, Ratio of A and U is not the same,
ratio of C and G is the same ratio of C and G is not the same

Carry genetic information Involve in protein synthesis.



2.0 CELL STRUCTURE
AND FUNCTIONS
TECHNOLOGY

2.0 CELL STRUCTURE
AND FUNCTIONS

TECHNOLOGY

COURSE LEARNING OUTCOMES

2.1 CELL STRUCTURE AND FUNCTIONS

a) State the three principles of cell theory. (CLO1)
b) Explain the structures of prokaryotic & eukaryotic cells. (CLO3)
c) Illustrate and compare the structures of prokaryotic & eukaryotic cells (plant and animal

cells). (CLO3)

2.2 STRUCTURE & FUNCTIONS: CELL MEMBRANE & ORGANELLES

a) Show the detailed structures of typical plant and animal cells and state the organelles
present. (CLO1)

b) Explain the structures and functions of the following organelles: Nucleus, rough,
endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome,
mitochondria, chloroplast and centriole. (CLO3)

c) Show the structure of plasma membrane based on Fluid Mosaic Model (CLO1).
d) Explain the structure of plasma membrane and the functions of each of its components

(CLO3).

2.3 CELLS ARE GROUPED INTO TISSUES

a) Describe animal tissues and plant tissues (CLO3).
b) Explain the following types of cells and tissues i) Animal cells & tissues: (CLO3)
c) Explain the following types of cells and tissues - Plant cells & tissues: (CLO3)

Meristem, parenchyma, collenchyma, sclerenchyma, xylem and phloem.

2.4 CELL TRANSPORT

a) Overview the various transport mechanisms across the membrane (CLO1)
b) Explain the various transport mechanisms across the membrane (CLO3)

i. Passive transport: Simple diffusion, facilitated diffusion and osmosis
ii. Active transport: Sodium-potassium pump and Bulk transport (endocytosis and

exocytosis)

2.1 CELL STRUCTURE AND FUNCTIONS

a) State the three principles of cell theory. (CLO1)

THREE PRINCIPLES OF CELL THEORY:
i. The cell is the building block of structure in living things.
ii. The cell derived from other cells by division.
iii. The cell contains inherited information which controls their activities

(example for growth, development & cell functioning).

b) Explain the structures of prokaryotic & eukaryotic cells. (CLO3)

Types of Cells

Prokaryotic cell Eukaryotic cell

Prokaryotic cell Eukaryotic cell

i. Pro means before & karyo means nucleus. i. Unicellular, filamentous, multicellular

ii. More primitive than eukaryotic cells. organism with large cell compare to

iii. Small & structurally simple – 0.5 to 5 µm in prokaryote. Based on structure, 2 types:

diameter. Animal cell and Plant cell
iv. Organisms made of prokaryotic cells are ii. Large in size, 10 – 100 µm in diameter.

called prokaryotes. iii. Organisms made of eukaryotic cells are

v. Prokaryotic cells have no true nucleus / no called eukaryotes.

distinct nucleus (they do not have iv. The cytoplasm of eukaryotic cells is

membrane bounded nucleus). presence of membrane bounded

vi. DNA is located in an unbound region called organelle; Mitochondria, endoplasmic

the nucleoid. reticulum, Golgi body, lysosomes & vacuoles.

vii. Prokaryotic cells also do not have v. Eukaryotic cells have a true nucleus /

membrane-bound organelles such as distinct membrane-bound nucleus.

mitochondria, endoplasmic reticulum, vi. Eukaryote has linear DNA associated with

viii. Golgi apparatus & vacuoles. histone protein contained within a nucleus.

ix. Lysosomes are absent. vii. Flagella or cilia when present, constructed

x. Prokaryotic DNA is circular. DNA is not from a system of complex arrangement 9+2

associated with histone microtubules and flagella are made of

xi. protein; it is not formed into chromosomes. tubulin.

xii. Prokaryotes reproduce asexually generally viii. Plant cells & algae have cell walls. Plant cell

by binary fission, a process in which one wall composed of cellulose while for fungi

cell divides into two similar cells. cell wall compose of chitin.

xiii. The ribosomes are composed of a 50S & a

30S subunit forming a 70S ribosome.

xiv. Some prokaryotes are photoautotroph. No

chloroplast. Photosynthesis (certain

bacteria) usually takes place in infolding or

extensions derived from the cytoplasmic

membrane.

xv. The plasma membrane develops extensions

into the cytoplasm called mesosomes for

cellular respiration.

xvi. Some bacteria may have other small rings of

DNA called plasmid that replicate separately

from the bacterial circular DNA.

xvii. Bacteria have a rigid cell wall outside the

plasma membrane which contain

peptidoglycan.

- Important: It provide support &

maintain the cell shape, protects the

cells & prevents it from bursting in

hypotonic environment.

xviii. Some bacteria have flagella for locomotion

that made up of flagellin, simple microtubule

without 9+2 microtubule.

xix. Some prokaryotes stick to their substrate or

to another by hair like appendages called

fimbriae (singular, fimbria).

xx. Sex pili are longer than fimbriae and allow

prokaryotes to exchange DNA during

conjugation.

Rod-Shaped
Bacterium, E.
coli, dividing by
binary fission
This image is
copyright Dennis
Kunkel.

c) Illustrate and compare the structures of prokaryotic & eukaryotic cells (plant and

animal cells). (CLO3)

SIMILARITIES

i) Both cells are surrounded by plasma membrane.

ii) Both cells are containing DNA.

iii) Both cells have ribosomes.

PROKARYOTIC CELLS EUKARYOTIC CELLS

i. Typical size ~ 0.5-5 µm in diameter Typical size ~ 10-100 µm in diameter

ii. Organization - usually single cells Organization- single cells, colonies, higher

multicellular organisms with specialized

cells

iii. Membrane-bounded organelles are Membrane-bounded organelles are present

absent

iv. Reproduce by binary fission Reproduce by Mitosis & Meiosis

v. Some bacteria have small circular DNA Plasmids are absent.

plasmids

vi. Some prokaryotes are photoautotroph. Chloroplast containing grana

Photosynthetic membranes not stacked

into grana. No chloroplast

vii. No distinct nucleus Distinct membrane-bound nucleus

viii. DNA is circular and not associated with Linear strand of DNA (chromosomes) with
histone histone proteins

ix. Cellular respiration occurs at mesosomes Cellular respiration occurs in mitochondria
in bacteria
Nitrogen fixation- Eukaryotic cells do not
x. Nitrogen fixation - Some prokaryotic contain enzymes that can fix atmospheric
cells have enzymes that can fix
nitrogen
atmospheric nitrogen for use in amino
acid synthesis Movement by complex flagella made up of
tubulin with complex arrangement 9+2 of
xi. Move by simple flagella made up of microtubules
flagellin without 9+2 arrangement of Cellulose cell walls for plants & chitin cell
microtubule walls for fungi.

xii. Cell walls present, made up of murein/
peptidoglycan

Illustration of Prokaryotic cells vs Eukaryotic cells

2.2 CELL STRUCTURE AND FUNCTIONS

a) Show the detailed structures of typical plant and animal cells and state the
organelles present. (CLO1)

PLANT CELL ANIMAL CELL

Differences between plant & animal cell

Animal cell Plant cell
No cell wall, surrounded only by plasma Surrounded by a plasma membrane & a

membrane cellulose cell wall
Shape is irregular & can be altered Has fixed, regular shape
Contains chloroplast to carry out
Do not have chloroplast
photosynthesis
Small vacuole Has a large central vacuole that surrounded

Cytoplasm, organelles & nucleus are not by tonoplast.
pushed to the periphery (the outer edge of Cytoplasm, organelles & nucleus are usually
pushed to the periphery due to the presence
particular area)
Food is stored in the form of glycogen of the large central vacuole
Food is stored in the form of starch granules
granules
Has a pair of centrioles No centrioles (except in lower plant)
Lysosomes almost always present Lysosomes not normally present except -

Naphentes sp.

b) Explain the structures and functions of the following organelles: Nucleus, rough,
endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome,
ribosome, mitochondria, chloroplast and centriole. (CLO3)

No. Organelles and its Component Structure Function

1) Nucleus - The largest 1) Acts as the

organelle in the centre to control

cell (10–20 µm in the activities &

diameters). cell division.

1) Nuclear 2) Organizes the
membrane / chromosomes
nuclear for cell division
envelope. and passes the
- Nucleus is chromosomes to
separated from the new cells.
the cytoplasm by
a double 3) Involved in the
membrane. production of
- The nuclear ribosomes
envelope is (rRNA).
covered with
numerous pores. 4)Contains
- These pores genetic materials
control the of a cell in the form
exchange of of chromosomes.
material between
the nucleus & the 5) Carry out
cytoplasm.
instructions for the
2) Nucleoplasm
- Semi-fluid matrix synthesis of
that fills the
nucleus. proteins (also
- Consists of
chromatin; enzyme) in the
histone protein
bound to DNA. nuclear DNA.

3) Nucleolus 6) DNA is
- Within the organized into
nucleus are one genes, which are
or two small templates used in
spherical in shape protein synthesis.
called nucleolus.
- Dense mass of
granules/ fibres,
non-membranous.

2) Endoplasmic Reticulum (ER) - ER consists of a
network of
membranous
tubules & sacs
called cisternae.
- It originates from
the outer
membrane of the
nuclear envelope.

- The presence of - To package &
ribosome gives a transport
granular proteins made by
appearance. the ribosomes.
- The rough
a) Rough Endoplasmic Reticulum (RER) endoplasmic
reticulum consists
of an
interconnected
system of
membrane-
bound flattened
sacs called
cisternae.

b) Smooth Endoplasmic Reticulum - The SER has no 1) Participates in
(SER) ribosomes & the synthesis of
interconnected lipids,
3. Golgi Body tubules. phospholipids
and steroids.
- Consists of a 2) Detoxifies
drugs and
stack of poisons.
3) Stores
flattened, calcium ions
which are
membrane- necessary for
muscles
bound sacs contraction.

called cisternae. - The main
functions of the
- Each stack Golgi body are to
modify, sort,
contains about 4 – stores & ship
(transport) cell
7 cisternae. products.
- Transporting &
- Golgi body has storing lipids.
- Forming
two faces, the cis lysosomes
containing
face & the trans hydrolytic
enzymes.
face. - Production of
digestive
- The cis face is enzymes.

located near the

endoplasmic

reticulum & is the

receiving side of - Secretion of
the Golgi body. carbohydrates for
- The trans face is the formation of
located near to the plant cell walls &
cell surface insect cuticles.
membrane.

4. Mitochondria - Rod-shaped - Sites of cellular
5. Lysosome structures that respiration.
vary in size & - The highly
shape. folded cristae
- Have their own increase the
DNA. surface area for
- Bounded by 2 the electron
membranes, a transport
smooth outer chain(ETC)
membrane & a reactions.
highly folded inner
membrane called
cristae.
- The inner
membrane
encloses the
mitochondrial
matrix,
a fluid-filled
space with DNA,
ribosomes and
enzymes.

- Small vesicle 1) Autophagy -
Release enzymes
formed when a that destroy /
engulfs worn-out
small piece of the organelles in the
cell.
Golgi body is 2) Autolysis -
The lysosome’s
pinched off at the membrane breaks
down, releasing
end. its enzymes &
digesting the
- Lysosomes is entire cell; self-
destruct.
single 3) Digest material
that has been
membrane- taken into the cell
via
bounded which phagocytosis.
4) Release
contains a enzymes to the
outside of the cell
variety of to digest other
cells in a process
hydrolytic known as
exocytosis.
enzymes that can

digest materials

within the cell.

6. Ribosome - Small, dense - Sites of protein
7. Chloroplast synthesis in the
particle found in cell.
8. Centriole
huge numbers in

all cells.

- Made up of

ribosomal RNA &

protein.

- Composed of

two subunits:

large and small

subunits.

- Can be found

suspended freely

in the cytosol, or

bound to the

endoplasmic

reticulum or

nuclear envelope.

- Lenses-shape - Site of
(biconvex), size: photosynthesis.
about 3-10 µm in - Main function: to
diameter & 2-3 trap/ absorb/
µm in thickness. capture light
- Enclosed by a energy// site for
double light dependent
membrane reaction.
separated by a
narrow inter
membrane space.
- Innermost
membrane is a
fluid-filled
space, the
stroma.
- A series of
interconnecting
flattened
membrane-
bounded sacs,
the thylakoids, are
found in the
stroma.
- Stroma contains
DNA, ribosomes,
and enzymes for
part of
photosynthesis.

- Found in animal - Act as
cells. organizers of
- Made up of two spindle fibres &
shorts bundles of are involved in the
microtubules separation of
positioned at right chromosomes/
angles to each chromatids during
other. cell division.
- The wall of each - In some cells,
centriole is made centrioles divide
up of nine triplets to produce basal

of microtubules body from which
arranged at an flagella & cilia
angle. develop.

c) Show the structure of plasma membrane based on Fluid Mosaic Model (CLO1).

Fluid Mosaic Model - Structure

Components Major phospholipids
Others globular
proteins

carbohydrate

cholesterol

i. 1972, S.J. Singer and G.L. Nicolson proposed the Fluid Mosaic Model.
ii. Cell membrane consisting of a bilayer of phospholipids with various protein molecules

embedded & attached to it.
iii. This structure is ‘selectively permeable’ meaning that it allows the passage of some

molecules (especially of water), but not of others.
iv. According to this model, it is called a:
v. Mosaic because the proteins are embedded in the phospholipid bilayer.
vi. Fluid because the proteins and phospholipids are free to move. They can only move

from side to side (lateral movement) or Flip-flop movement, however, not through the
membrane.

d) Explain the structure of plasma membrane and the functions of each of its
components (CLO3).

No Structure Function
1. Phospholipids bilayer i) Forms boundary to isolate cell contents
from environment.
i) Membrane is 8 nm thick. ii) Restricts passage of hydrophilic
ii) It consists of a phospholipids bilayer: substances across the membrane
- The polar hydrophilic (water (selective permeable membrane).
attracting) head of phospholipids facing
outwards. i) Transport: A protein that spans the
and membrane may provide a hydrophilic
- The non-polar hydrophobic (water channel across the membrane that is
fearing) tails facing in towards the selective for a particular solute.
middle of the bilayer. ii) Enzymatic activity: Some membrane
proteins act as enzymes. that ordered as
2. Two types of Globular proteins: a team that carries out sequential steps in
i) Integral / intrinsic proteins are metabolic pathway.
partially or fully embedded in the iii) Signal transduction: A membrane
membrane & intrinsic protein that protein may have a bonding site with
penetrate all the way through the specific shape of a chemical messenger,
phospholipid bilayer is called such as a hormone.
transmembrane proteins. iv) Intercellular joining: Membrane
ii) Peripheral / extrinsic proteins on proteins of adjacent cell may be hooked
the outer or inner surfaces of the together in various kinds of junction:
membrane. - Tight junction – prevents leakage of
extracellular fluid across a layer of
epithelial cell.
- Gap junction (communicating junction),
provide cytoplasmic channels from one
cell to an adjacent cell.
v) Cell recognition: serve as
identification tags that are specifically
recognized by other cells.
vi) Attachment to the cytoskeleton &
extra cellular matrix (ECM): helps
maintain cell shape & fixes the location
of certain membrane proteins.

3. Carbohydrate i) Glycoprotein: Cell recognition and

- Glycoproteins are formed when have important roles in protection & the

proteins on the outer phospholipid layer immune response, reproduction & cell

combine with carbohydrate. adhesion.

- Glycolipids are formed when short ii) Glycolipid: Cell recognition and

carbohydrate chain covalently attached provide stability & help cells join to

this is exposed on the outer surface of other cells to form tissues.

the cell.

4. Cholesterol i) Maintain fluidity of membrane
- Located between phospholipid - At moderate temperature, it reduces
(hydrophobic tail) molecules in plasma membrane fluidity by reducing
membrane. phospholipid movements, but at low
temperature, it prevents solidification of
phospholipids.

2.3 CELL ARE GROUPED INTO TISSUES

a) Describe animal tissues and plant tissues (CLO3). Diagram

Description

i. Cells as basic units of living organisms
are grouped into tissues & organs.

ii. Cells in multicellular organisms do not
function in isolation.

iii. Groups of cells of the same type
(performing similar functions) form
tissues & act as a unit.

iv. An organ consists of several types of
tissues that work together to perform
specific functions.

b) i) Explain the following types of cells and tissues i) Animal cells & tissues: (CLO3)

- Epithelial cells (simple squamous, simple cuboidal, simple columnar, stratified squamous),
- Nerve cell (motor neuron),
- Muscle cells (smooth, striated and cardiac muscle),
- Connective tissues (compact bone, hyaline cartilage and blood)

1) Epithelial Tissue

No. Tissue Structure Location Function
1. Simple squamous epithelial - Single layer - Lining of - Diffusion of
of cells the blood material.
tissues attached to vessel. - Exchange of
the basement - Lining of gaseous across
2. Simple cuboidal epithelial membrane. the lymphatic the membrane.
tissues - Cells are vessels.
flattened and - Lining of Secretion &
3. Simple columnar epithelial thin with the alveoli of absorption.
tissues central the lungs.
nucleus. Protection,
- View from - Lining of absorption &
the surface, salivary secretion.
they are glands,
polygonal- pancreatic - The secreted
shape. duct, thyroid mucus serves as a
- Single layer gland, lubricant for the
of cuboidal proximal & linings of the
shape cells. distal digestive & upper
- Central convoluted respiratory tracts.
spherical tubules.
nucleus. - Lining of
digestive
- Columnar tract, small
shape with intestine,
oval nucleus upper
near its basal respiratory
end. tract &
- Apical oviducts.
surface may
have cilia/
microvilli.
- Cells are
usually
associated
with goblet
cells (are
modified
columnar cells

4. Stratified squamous epithelial that secrete - Lining of - Resists
tissues mucus). the abrasion.
- Made up by oesophagus - Acts as a barrier
several layers - Lining outer (prevent water loss
of cells skin through skin).
(cuboid in - Lining the
shape become vagina
flattened - Lining the
squamous). anus
- Only the cells - Lining the
of deepest mouth
layer attached
to basement
membrane.

2) Nerve Cell i. e
i) The functional "unit" of nervous tissue
d
is the nerve cell called neuron. f
ii) Each neuron is composed of 3 main i
b
parts: r
a. Cell body - Contains nucleus. e
b. Dendrites - Highly branched

fibres.

iii) Three types of neurons:
a. Afferent (sensory neurons)
b. Efferent (motor neurons)
c. Interneuron/ Intermediary (relay
neurons)

a) Structure: known as
Motor Neurons.
Consist cell body, dendrite &
axon.

b) Distribution of cells:
Brain & spinal cord.

c) Function:
Conduct impulses out of
CNS toward muscles &
glands (effector).

Muscle Tissue 3) Muscle Tissue Function Location
Skeletal tissue - Responsible - Attached to
Structure for voluntary bones by
Cardiac tissue - Long, movement of the tendons.
cylindrical shape & are body.
Smooth tissue arranged parallel to one
another.
- Each muscle fibre is
multinucleated with the
nuclei at the periphery &
located just beneath the
cell surface membrane.

- Have one or two - Responsible - Lining at the
nuclei per fibre with for involuntary wall of heart.
many mitochondria. movement of the
- Muscle cells are heart by form
connected to one continuous,
another by intercalated rhythmic
discs. contractions &
- The muscle fibres allow heart pump
striated, branch & blood around the
form bridges with one body.
another to form a
netlike arrangement.

- Each muscle fibre - Responsible - Lining the walls
consists of a single, for involuntary of arteries &
elongated spindle- movement of the veins, the
shaped cell containing body. digestive tract, the
one centrally located urinary bladder &
nucleus. the uterus.
- The muscle fibres do
not contain cross
striations.
- The contractile protein
filaments are not
arranged in the same
patterns.

4) Connective tissue

a) Compact bone

- Compact bone consists of living cells,
30% of collagen (give bone its strength),
70% inorganic substances (give bone its
hardness).
- The bone cells called osteoblasts, matured
called osteocytes.
- Osteoblasts secrete & maintain the matrix of
collagen.
- The matrix is arranged in concentric circles,
called lamellae.
- Osteocytes are found in spaces in the lamellae
known as lacunae.

Location: Skeleton
Function:
- Give body shape & provide framework for
support.
- Protect the internal organs
- Provide surfaces for attachment of skeletal
muscles to enable movement.
- Act as a reservoir for calcium & phosphorus.
- Site for blood cell production in the bone
marrow

b) Hyaline cartilage

- Has an abundance of collagenous fibres
embedded in a rubbery matrix called
chondroitin sulphate.
- Chondroitin sulphate & collagen are secreted
by chondrocytes.
- Blood vessels do not penetrate cartilage;
oxygen & nutrients reach these cells by
diffusion, and waste products diffuse away.
- Each chondrocyte is placed within a lacuna.
Some lacunae may enclose even two, four or
eight chondrocytes

Location: Trachea & bronchi.
It forms the embryonic skeleton in many bony
vertebrates.
It covers the end of bones & reduces friction
between joints during movement.

It forms the skeleton of cartilaginous
fish.rays.waste products diffuse away

Function: Give flexible support.

c) Blood

Erythrocytes Leucocytes Platelets
Structure: - Fragments cells, about 2-3 μm
- Covered by a thin & elastic Structure: in diameter.
cell surface (allow it to pass - Contain nucleus & organelles
through small blood capillary). - Lack the pigment haemoglobin. - No nucleus and have lifespan
- Biconcave shape - Irregular in shape.
- Lose their nucleus during Ratio of leucocytes to erythrocytes is about 10 days
maturation. about 1: 700 - Originate as pinched – off
- Contain pigment
haemoglobin. cytoplasmic fragments of large

Functions: cells in the bone marrow
Transport O2 & CO2
Function: Function:
Fight infection / immune system Process of blood clotting

b) ii) Explain the following types of cells and tissues - Plant cells & tissues: (CLO3)
Meristem, parenchyma, collenchyma, sclerenchyma, xylem and phloem.

Classification of Plant Tissue

1) Meristem cells

i) Composed of young & immature cells which are in a state of division & growth cells.
ii) Have large nucleus located in the centre & dense cytoplasm.
iii) Cells are similar in structure & have thin cellulose cell walls.
iv) Cells are closely packed & without intercellular air spaces.
v) Shape of the cell may be spherical, oval, polygonal or rectangular.
vi) Contain few vacuoles or no vacuoles at all.
vii) Have ability to divide by mitosis & differentiate into specialized cells.
viii) Three type of meristem cells: Apical meristem, Lateral meristem & Intercalary

meristem.

1) Apical meristem 2) Lateral meristem 3) Intercalary meristem

Structure of - provide additional - Growth in thickness, - Meristem at the base of
cell cells that enable known as secondary the internode (between leaf
growth in length growth, is caused by nodes) & enables
known as primary lateral meristems called the longitudinal growth of the
growth. vascular cambium and cork stem.
cambium.

Distribution - Root tips & shoot - Found in all woody - Common in grasses &
buds. plants & in some bamboo (occur at bases of
herbaceous plants. nodes).
Function - Begin growth of new - Helps regenerate parts
cells in young - Responsible for removed
seedlings at the tips of secondary or lateral
roots & shoots growth which constitute - Stem elongation in very
the secondary plant body. short time.

Diagram

2) Permanent tissues
- Two types of permanent tissue:

1) Ground Tissues 2) Vascular Tissues
- Parenchyma - Xylem
- Collenchyma - Phloem
- Sclerenchyma

Parenchyma 1) Ground Tissues Sclerenchyma
Collenchyma

- Consist of unspecialized - Nucleus present, consist of - Have primary & secondary
living cells, with nucleus living cells. cell wall.
present in the cells. - Polygon-shaped & - Have thick (secondary) cell
- Usually isodiametric or elongated. wall containing lignin.
elongated cells. - Cells are closely packed - Cell walls are evenly
- When mature, have a large together with very small or no thickened.
central vacuole with the intercellular spaces. - No nucleus when mature,
cytoplasm pushed to the cell - Have unevenly thickened these cells usually die after
periphery. primary cell wall with deposits maturity.
- Have primary cell walls that of cellulose, pectin & - Elongated, polygonal-
are thin and flexible and most hemicellulose shaped with tapering ends.
lack secondary walls. - The thickenings usually occur - Cells have no protoplasm
- Cell wall containing cellulose, at the corners of the cell walls. with narrow empty lumen.
hemicellulose & pectin. - Pits are present between cell - Pits are present in the cell
- Cells are loosely packed wall walls.
together/ large intercellular - Cells are closely packed
space. together/no intercellular air
space.

Distribution: Distribution: Distribution:
- Cortex & pith of stem. - Along midrib of leaves. Just - Xylem & phloem
under stem epidermis. - Cortex below the epidermis
Function : - Below the epidermis in the of stems & roots.
1) Perform most of the outer region of the cortex &
metabolic functions of gradually merges into Function :
plants, synthesizing and parenchyma towards inside. 1) Provide the plant with
storing various organic Function : mechanical strength &
products. 1) Giving mechanical strength rigidity.
2) Retain the ability to divide & flexibility. 2) It acts as supporting
and differentiate into other 2) Elastic support. tissue.
types of plants. 3) To provide supporting
3) Gaseous exchange. tissue for the herbaceous
plants (non woody plants).

3) Vascular Tissue

Xylem Phloem
- Consist of two cell type: tracheids & vessel - Consist of two cell type: Sieve tube elements
element & Companion cells
- Both with secondary walls & dead at functional - Specialized to transport organic
maturity substances from leaves to storage organs
- Function in transporting water & dissolved & growing parts of plant body.
mineral salts to the upper parts of the plant. - Alive at maturity, but usually with a much
reduced cell contents & no nucleus.

TRACHEIDS SIEVE TUBES ELEMENTS
- Long, thin, tapered cells having lignin- - Consists of sieve tube element joined
hardened secondary wall with pits together to form a long tube.
- All vascular plants possess tracheids. - Their end walls are perforated forming sieve
- Water flow from cell to cell through pits (water plates with sieve pores.
transport) & also function in mechanical support. - The sieve tube element does not have lignin
in their walls (has cellulose).
- Their nuclei degenerate & are absent as they
mature.

VESSEL ELEMENT COMPANION CELLS
- Wider, shorter, thinner-walled & less tapered - Have nucleus, dense cytoplasm with a
than tracheids. small vacuole.
- End walls of the vessel elements have - They are metabolically active & have
perforation plates that enable water to flow numerous mitochondria & ribosomes.
freely through the vessels - Linked by numerous plasmodesmata to sieve
- Have larger diameter & specialized for water tube elements
transport & fibers for mechanical strength.