CHAPTER 2 CELL BIOLOGY AND ORGANISATION

CHAPTER 2
CELL BIOLOGY

AND
ORGANISATION

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2.1 CELL STRUCTURE AND FUNCTION

 CELL are the basic units of all living things
 There are two types of cells

Animal cellPREPARED BY CIKGU HUSRITA MRSM TRANSKRIAN Plant cell

THE STRUCTURE OF ANIMAL CELL

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THE STRUCTURE OF PLANT CELL

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ORGANELLE

An organelle is a tiny cellular structure that performs specific
functions within a cell

• Mitochondrion • Ribosome
• Centriole • Endoplasmic

• Golgi apparatus reticulum
• Lysosome • Vacuole
• Nucleus • Chloroplast

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MITOCHONDRION
(PLURAL:MITOCHONDRIA)

CHARACTERISTIC:
 It is rod-shaped or spherical
 It consists of two layers of membranes, which are the
 smooth outer membrane and folded inner membrane
 Contains enzymes that play a role in cellular respiration

FUNCTION :
• A site that generates energy through the glucose oxidation

process during cellular respiration
• Energy released in the form of ATP molecules (adenosine
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CENTRIOLE

Characteristic
• Small cylindrical components that exist in pairs in

animal cells
• Made up of complex arrangement of microtubules

Functions
•Forms spindle fibre during cell division in animal
cells
•does not exist in plant cell

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GOLGI APPARATUS Characteristic
• Consists of a stack of parallel flattened sacs that are
coated by a single cell membrane
• New membrane is added at one end of the Golgi
apparatus and vesicles bud off from the other end.

Functions
• Processes, modifies, packs and transports chemicals

such as protein, carbohydrate and glycoprotein
(combination of carbohydrate and protein) that is
carried by transport vesicles
• these products will be pack into vesicles and carried to
other parts of the cell or to the plasma membrane (to
be release outside the cell)

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PLASMA Characteristic
MEMBRANE • Outer membrane that surrounds the entire content of cell
• Made of proteins and phospholipids
• Thin and elastic film
• Partially permeable

Functions
• Separates content of cell from the external environment
• Controls movement of substances into and out of the cell
• Allows exchange of nutrients, respiratory gases and

waste materials between cells and their surroundings

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LYSOSOME Characteristic
• Small spherical sac enclosed in a single

membrane
• Contains hydrolytic enzymes
Function
• Hydrolyses complex organic molecules such as

protein, nucleic acid and lipid
• Breaks down components of damaged cells

(suicide bag)
• eliminate worn out organelles
• In certain organisms, fuse with food vacuole

and dispense enzyme into the vacuole to digest
the content

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NUCLEUS Characteristic
• Largest component in the cell
• Spherical, compressed and enclosed in a

nuclear membrane with many pores
• The nucleus contains chromosomes, nucleolus

and nucleoplasm.
Function
• Controls all cell activities
• Has chromosomes that contain

deoxyribonucleic acid (DNA).
• DNA determines the cell characteristics and

metabolic function.

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RIBOSOME Characteristic
• Small, compact and spherical granules
• Attach to the surface of rough ER or suspended

freely in the cytoplasm
• Consists of protein and ribonucleic acid (RNA)
• Ribosomes are present on the surface of the rough

endoplasmic reticulum or exist freely in the
cytoplasm.
Function
• Site for protein synthesis (eg:enzymes)

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ENDOPLASMIC Characteristic
RETICULUM • Consists of a system of interconnected folded flattened sacs
• Endoplasmic reticulum membrane is continuous with the

nuclear membrane.
• There are two types of endoplasmic reticulum:

– Rough endoplasmic reticulum has ribosomes
attached to the surface

– Smooth endoplasmic reticulum does not have
ribosomes

Function
• The transport system within the cell
• Provides a wide surface for enzyme attachment and

biochemical reactions
• The rough endoplasmic reticulum transports proteins

synthesised by ribosomes.
• The smooth endoplasmic reticulum synthesises and

transports glycerol and lipids, and carries out the
detoxification of drugs and metabolic by-products

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VACUOLE Characteristic
• Liquid-filled sac, which is the cell sap.
• A vacuole is surrounded by the tonoplast membrane.
• Young plant cells have many small vacuoles while

mature plant cells have a large vacuole.
• The vacuole in animal cells is small.
• Cell sap contains water, organic acids, sugars, amino

acids, enzymes, mineral salts, oxygen, carbon dioxide
and metabolic by-products
Function
• Water is absorbed into the vacuole plant cell and the
cell becomes turgid.
• In unicellular animals, the vacuole contracts during
osmoregulation, osmosis and excretion.

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CHLOROPLAST Characteristic
• Oval shaped
• Consists of two layers of membrane
• Contains chlorophyll pigments in the grana that

give plants a green colour

Function
• Chlorophyll absorbs sunlight and converts

it to chemical energy during
photosynthesis.

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CYTOPLASM Characteristic
• medium that contains components of the

suspended cells
• Contains organic compounds (such as protein,

lipid and carbohydrate) and inorganic compounds
(such as potassium ions)
Function
• Acts as a medium for biochemical reactions in
cells

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CELL WALL Characteristic
• A strong and rigid outer layer
• Made from cellulose fibre
• Fully permeable

Function
• Maintains the shape of plant cells
• Provides mechanical support to plant

cells

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Does not have a fixed shape Has a fixed shape

Does not have a cell wall • nucleus Has a cell wall
• cytoplasm Has chloroplasts
Does not have • plasma
chloroplasts Does not have
membrane a centriole
Has centrioles • Golgi apparatus
Stores carbohydrate
Stores carbohydrate mitochondrion in the form of starch
in the form of • endoplasmic
glycogen
reticulum

ribosomes.

No vacuole/if present, it is small Has a large vacuole

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2.2 LIVING PROCESSES IN UNICELLULAR ORGANISMS

 Unicellular organisms are made up of only one cell.
 Unicellular organism carry out all life processes such as respiration,

movement, nutrition, responding to stimulus, reproduction, growth and
excretion

Amoeba sp. STRUCTUREPREPARED BY CIKGU HUSRITA MRSM TRANSKRIAN

Paramecium sp. structure

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Amoeba sp. and Paramecium sp.

MOVEMENT

• Amoeba sp. constantly changes its

shape when it encounters obstacles.

Amoeba sp. moves by extending out

its pseudopodium (false feet).
• This is followed by the flow of
cytoplasm into the extended
pseudopodium.

• Paramecium sp. moves using rhythmic

cilia beats.

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Amoeba sp. and Paramecium sp.

NUTRITION
 Amoeba sp. moves towards food by extending
its pseudopodium to trap food particles by
phagocytosis.
 Paramecium sp. the presence of cilium beat
helps transfer food particles into the oral
groove.
 The food vacuole is combined with lysosome.
 The food particles are hydrolysed by the
enzyme lysozyme in the lysosomes.
 The nutrients are absorbed into the
cytoplasm.
 Undigested food is discharged when the
Amoeba sp. moves. Undigested food in the
Paramecium sp. is discharged through the
anus.
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Amoeba sp. – Feeding
(Phagocytosis)

Amoeba extending Surrounds and Formation of food
pseudopodia engulf food particle vacuole

Microscopic view:

AmoebaPhagfeoecdyitnogsis on

protista

Food is digested and nutrients Lysozyme secreted

are absorbed into cytoplasm into food vacuole

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Amoeba & Paramecium sp.

REPRODUCTION Conjugation is the
process by which one
• When the conditions are suitable and there is plenty bacterium transfers

of food, Amoeba sp. and Paramecium sp. will genetic material to
another through direct
reproduce via asexual reproduction that is binary
fission through mitosis. contact.
• However, when the environmental conditions are not
suitable, such as dry conditions, low temperature

and food shortage, the Amoeba sp. forms spores

that will only germinate when the environment
improves.

• For Paramecium sp., sexual reproduction, that is

conjugation occurs when environmental conditions
are not suitable.

Eg:starvation,shortage

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CONJUGATION IN Paramecium sp. BINARY FISSION IN Paramecium sp.

(SEXUAL REPRODUCTION) (ASEXUAL REPRODUCTION)

BINARY FISSION IN

Amoeba sp.

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Amoeba & Paramecium sp.

RESPONDING TO STIMULI RESPIRATION

• Amoeba sp. and Paramecium sp. • Exchange of oxygen and carbon dioxide
gases occur through the plasma
respond to
• stimuli such as chemicals, touch or
bright light by moving away from the membrane by simple diffusion on the
stimuli surface of the cell.
• In contrast, favourable stimuli such
as contact with food causes it to EXCRETION

move forwards • Waste such as carbon dioxide and ammonia are
removed by diffusion.
• As Amoeba sp. and Paramecium sp. live in freshwater
GROWTH environments, water will diffuse by osmosis and fill the

• Amoeba sp. and contractile vacuole.
Paramecium sp. grow by • When the vacuole expands to the maximum size,

synthesising new cytoplasm. contraction occurs and water is excreted from time to
time.
• This process isPREPARED BY CIKGU HUSRITA MRSM TRANSKRIAN called osmoregulation.

2.3 LIVING PROCESSES IN MULTICELLULAR ORGANISMS

 There are various types of cells in multicellular organisms which are
different in size, shape and arrangement.

Muscle cell Nerve cell White Blood Cell
 arranged as multinuclear  long and thin in shape  Can change shape
 Functions in sending  Functions in destroying
striated fibres
 Contract and relax to nerve impulses pathogens

generate movement

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Epithelial Cell Sperm Cell Red Blood
 Thin and flat cells  Has a long tail to enable it Cell
 Coats the surface of organs
such as the digestive tract to swim towards the ovum  Does not contain a nucleus
in the fallopian tube  Shaped as a biconcave disc

 The head carries a set of  Functions to optimize
chromosomes from the transportation of oxygen
male

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Sieve Tube Element Xylem Vessel Palisade Mesophyll Cell
 Long cylindrical tubes  Long, continuous hollow  Consist of long cylindrical

arranged from end to end tube cells, arranged vertically
 Transport organic materials  Functions in transporting and close to each other
 Contains high chlorophyll
from leaves to storage water and mineral salts density
organs such as fruits from the roots to the other  This arrangement allows
parts of the plants maximum absorption of
sunlight for photosynthesis

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Spongy Mesophyll Guard Cell Root Hair Cell
 Cells are loosely arranged  Modified lower epidermal  Has a long projection which

with lots of air space in cells with the thicker cell adds surface area for the
between wall on the inner side absorption of water and

 Large air space allows  Controls the opening and mineral salts
exchanged of gas from the closing of the stoma.
inside of the leaves to the
 Stoma is the opening that
palisade mesophyll cells allows the exchange of

oxygen and carbon dioxide

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Cell Organisation in Humans

 Tissues are group of cells that have the same structure and function
and are arranged together to carry out a specific functions

 Tissues can be classified into four different types :
i. Epithelial tissues
ii. Muscle tissues
iii. Nerve tissues
iv. Connective tissues

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EPITHELIAL TISSUES

• Epithelial tissues : covers the outer surface (skin) and hollow
surfaces in the body (digestive tract and
respiratory tracts)

• The epithelial tissues structure is adapted based on its
function

• Examples : epithelial tissues on the skin protects against
infection, injuries, chemical and dehydration

• Epithelial tissues that coat the trachea have projections like
hair, known as cilia

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Epithelial tissues : covers the
surface of the mouth and
oesophagus
Epithelial tissues : covers the surface of
lung, body cavities and blood vessels

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Epithelial tissues : covers the
surface of the trachea and bronchus

Epithelial tissues : lines tubules,
glands and kidney ducts
Epithelial tissues : covers the small
intestine

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Smooth muscle MUSCLE TISSUES Cardiac muscle
Found in the digestive tract, blood Found in the heart wall
Skeletal muscle
vessel, urinary tract and Found in legs and hands
reproductive tract

Contraction and relaxation of  Involved in controlled  Builds walls of the heart
smooth muscle enable involuntary movement that contract to pump blood
activities such as peristalsis along to the whole body
 Contract and relax to generate
the digestive tract movement in bones and limb  contraction is involuntary

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NERVE TISSUES
C1 : is made of neurone or nerve cells
C2 : Each neurone consist of a cell body
and nerve fibre called dendrite and axon
F1 : Can detect stimuli and then send
information in the form of an electrical
signal (nerve impulses) to the muscles or

glands
F2 : nerve tissue regulates and controls

body activities

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CONNECTIVE TISSUES

Loose Connective Tissue Fibrous Connective Tissue Blood Tissue
Link the epithelial tissue to the  These tissues form Plays a functional role in
regulation, transportation and
tissue below it and fixes the tendons and ligaments
organs in their positions  Tendon connects bones protection

and muscles
 Ligaments connect bones

to bones

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CONNECTIVE TISSUES

Bone Adipose Tissue Cartilage
Forms the body frame and  Keep fat under the skin Cartilage encloses bone tips to
protects the internal organs prevent the bone from wearing
dermis and the surface of
all main organs out

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TISSUE ORGANISATION IN PLANTS

PLANT TISSUES

MERISTEMATIC PERMANENT
TISSUES TISSUES

APICAL LATERAL EPIDERMAL TISSUES GROUND TISSUES VASCULAR TISSUES
MERISTEMATIC MERISTEMATIC

TISSUES TISSUES

PARENCHYMA COLLENCHYME XYLEM TISSUES
TISSUES TISSUES

SCLERENCHYME PHLOEM TISSUES
TISSUES

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Parenchyma Tissue Collenchyma Tissue Sclerenchyma Tissue
F1 : To store, protein and water F : giving support to young, F : in providing support and
F2 : This tissue also carry out non-woody stems (herbaceous mechanical strength to all mature

photosynthesis plants parts of the plant

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VASCULAR TISSUES – XYLEM
F1 : transporting water and mineral salts from

the roots to other parts of the plants
F2 : Ligneous xylem tissue wall provides

support and mechanical strength to the plants
VASCULAR TISSUES – PHLOEM

F : transporting organic matters such as
sucrose form the leaves to all parts
of the plant

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Density of Certain Cell Components and Specialised Cell Functions

Types of cell Cell component found in Function
abundance
Sperm cell
Mitochondria Requires a lot of energy to swim towards
Muscle cell such as flight muscle cells in insect the uterus and Fallopian tube to fertilise
and birds the secondary oocytes

Requires a lot of energy to contract and
relax to enable movement and flight

Plant meristem cell Requires a lot of energy to carry out active
cell division process to produce new cells

Palisade mesophyll cell Chloroplast Absorb more sunlight to carry out the
Spongy mesophyll cell process of photosynthesis
Pancreatic cell Rough Endoplasmic Reticulum
Golgi apparatus Increases synthesis and secretion of
Goblet cell in intestinal epithelium and digestive enzymes
respiratory tract Produce mucus
Liver cell
Smooth Endoplasmic Reticulum Metabolises carbohydrates
Detoxification of drugs and poisons
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2.4 LEVELS OF ORGANISATION IN MULTICELLULAR ORGANISMS

 Organ : a group of different tissues combine
together and perform special functions

 Heart : epithelial tissue – fills up space in the
heart

cardiac muscle tissue – functions in pumping
blood to the rest
of the body

connective tissue – such as blood connect the
system in the organ and

nerve tissue – regulates the rhythm of the
heartbeat

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2.4 LEVELS OF ORGANISATION IN MULTICELLULAR ORGANISMS

 System : a different organ work together to carry out a
specific function

 There are 11 main organ systems in the human body:
1. Respiratory system
2. Muscular system
3. Reproductive system
4. Endocrine system
5. Lymphatic system
6. Nervous system
7. Blood circulatory system
8. Digestive system
9. Urinary system
10. Skeletal system
11. Integumentary system

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2.4 LEVELS OF ORGANISATION IN MULTICELLULAR ORGANISMS

 Endocrine System :
C : the endocrine gland that secretes
hormones
F : coordinates body activities with the
nervouse system

 Respiratory System:
C : consist of Trachea, nose, lungs and

diaphragm
F : exchange of oxygen and carbon dioxide gases

between the body and external environment

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 Muscular System :
C : skeletal muscle, smooth muscle and

cardiac muscles
F : contract and relax to produce movement

 Skeletal System:
C : bone, cartilage, ligament and tendon
F : supports the body, protects the internal organs

and provides a base for muscle adhesion

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 Nervous System:
C : brain, spinal cord and peripheral nerves
F : detects and sends information in the
body, as well as coordinates body activities

 Lymphatic System:
C : spleen, lymph nodes and lymph vessels
F : maintains balance of bodily fluids and

prevents infectious diseases

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 Male Reproductive System:
C : Testes, prostate gland and penis
F : Produces sperm and male sex hormone

 Female Reproductive System:
C : ovary, uterus, fallopian tube, vagina and

cervix
F : produces ovum and female sex hormones

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 Blood Circulatory System:
C : Heart, artery, vein and blood capillary
F : Transports nutrients, respiratory gases
and waste products

 Digestive System:
C : Mouth, oesophagus, stomach, liver, pancreas,

small intestine and large intestine
F : digests food into simpler form for easy absorption

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 Urinary System:
C : Kidney, ureter, urethra and bladder
F : Eliminates waste products such as urea and

uric acid from the body

 Integumentary System:
C : Skin
F : protects the body from physical injury, infection

and dehydration

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