1. The document summarizes key organelles and their functions in plant and animal cells. It compares and contrasts the two cell types. 2. Key differences highlighted include the presence of a cell wall and chloroplasts in plant cells and their absence in animal cells. 3. The document also provides information on cell structure and function, including movement of substances via diffusion, osmosis and active transport.

1. Chapter 2: Cells
Animal cell Plant cell
*2, 11 and 14 not in syllabus. *5 not in syllabus
S/N Organelle Form Function S/N Organelle Form Function
Allows cer-
tain sub-
stances in
and out of
the cell by
Made of
Partially controlling
non-living Provides me-
permeable the size of
Cell surface and fully chanical sup-
1 biphospho- the pores. 1 Cell wall
membrane permeable port, gives cell
lipid mem- Movement
rigid cellu- its fixed shape
brane of particles
lose
based on
size and
concentra-
tion of par-
ticles.
Allows certain
Stores and substances in
modifies and out of the
Shaped like substances cell by con-
Partially trolling the
a disc, stack made by
permeable size of the
Golgi appara- of flattened ERs, pack- Cell surface
3 2 biphospho- pores. Move-
tus spaces sur- ages sub- membrane
lipid mem- ment of par-
rounded by stances in
brane ticles based on
membrane vesicles to
be trans- size and con-
ported out centration of
of cell. particles.

2. Contains en-
Gel-like
zymes and
protoplasm
Makes pro- organelles,
between
4 Free ribosome - teins for the 3 Cytoplasm medium for
nucleus and
cell’s usage cell’s bio-
cell surface
chemical reac-
membrane
tions.
Continuous
with nuclear Ribosomes More tubu-
envelope, on the RER lar than
Smooth en-
Rough endop- ribosomes makes pro- RER, con- Synthesis fats
doplasmic
5 lasmic reticu- attached to teins usually 4 nected to and steroids,
reticulum
lum (RER) outer sur- transported RER, no detoxifies cell.
(SER)
face of RER out of the ribosomes
(causes cell. attached
roughness)
Contains Contains
Nucleus Contains Nucleus
chromatin, chromatin, Contains ge-
9– genetic in- 9–
long thread- long thread- netic informa-
6, 7 (Nucleolus, formation 6, 7 (Nucleolus,
like struc- like struc- tion during
and Nucleoplasm, during pro- and Nucleoplasm,
tures with tures with protein syn-
8 Nuclear tein synthe- 8 Nuclear
DNA in DNA in thesis.
envelope) sis. envelope)
them. them.
Continuous
More tubu- with nuclear
Ribosomes on
lar than envelope,
Smooth en- Synthesis Rough en- the RER
RER, con- ribosomes
doplasmic fats and ste- doplasmic makes pro-
10 nected to 10 attached to
reticulum roids, detox- reticulum teins usually
RER, no outer sur-
(SER) ifies cell. (RER) transported
ribosomes face of RER
out of the cell.
attached (causes
roughness)
Contains
enzymes
Gel-like
and orga-
protoplasm
nelles, me- Makes pro-
between Free ribo-
12 Cytoplasm dium for 11 - teins for the
nucleus and some
cell’s bio- cell’s usage
cell surface
chemical
membrane
reactions.

3. Aerobic res- Oval struc-
piration oc- tures with
Small sau- curs here to membranes
Mitochon- Site for photo-
13 sage-shaped provide 12 Chloroplast containing
drion synthesis
organelle energy for chlorophyll
cellular ac- and fluid
tivities. stroma
Large cen- Contains dis-
Essential for tral vacuole solved sub-
Small hol-
cell division containing stances (eg.
- Centriole low cylind- 13 Vacuole
(mitosis/ cell sap that sugar, mineral
ers
meiosis) is enclosed salts and ami-
by tonoplast no acids)
Aerobic respi-
Temporary
Contain wa- ration occurs
fluid-filled Small sau-
ter and food Mitochon- here to pro-
- Vacuole spaces en- 14 sage-shaped
substances drion vide energy
closed by a organelle
temporarily. for cellular
membrane
activities.
Plant cell Animal cell
Cell wall present since plants do not have a skeletal Cell wall absent since animals have a skeletal sys-
system to provide support. tem to provide support.
Chloroplasts present to make food during photo- Chloroplasts absent since animals can move about
synthesis since they can’t feed. and feed to provide energy for their activities.
Centrioles absent for cell division. Centrioles present for cell division.
A large central vacuole that is permanent. Numerous, small and temporary vacuoles.

4. Cell structure Adaptation
1. No nucleus means more space in the cell to
carry more haemoglobin and hence more oxy-
gen.
Red blood cell
2. Circular biconcave shape increases surface area
to volume ratio, increasing the rate of diffusion
of oxygen in and out of the cell.
1. Do not have cross walls or protoplasm enables
water to move through the lumen easily with
little need to diffuse.
Xylem vessel
2. Lignin is deposited on the walls to strengthen it
and also to prevent the vessels from collapsing.
1. Root hair cell has a long and narrow protrusion,
increasing the surface area to volume ration of
Root hair cell
the cell, increasing the rate of absorption of wa-
ter into the root hair cell.
Organ
Cells Form Organs Form Form Organism
systems
Stomach cells + other cells  Stomach + other organs  Digestive system + other systems  Organism

5. Chapter 3: Movement of Substances (Diffusion, osmosis, active transport)
Type of movement Diffusion Osmosis Active transport
Diffusion is the net Osmosis is the net Active transport is the
movement of particles movement of particles process whereby energy
from a region of higher from a region of higher is used to move the par-
concentration to a re- water potential to a re- ticles against a concen-
gion of lower concentra- gion of lower water po- tration gradient from a
Definition
tion down a concentra- tential through a partial- region of lower concen-
tion gradient without the ly permeable membrane tration to a region of
use of energy, with or without the use of ener- higher concentration
without a partially per- gy.
meable membrane.
Nutrients diffuse into Due to turgor pressure Active transport is
ameoba to provide food (refer to below), non- needed in the uptake of
for the ameoba and woody plants are able to glucose in the villi in
waste products diffuse stand firm and erect. the small intestine to
out of the ameoba to increase the amount of
prevent accumulation of glucose being absorbed
harmful waste products. Certain flowers are able because the amount ab-
to open in the day and sorbed through diffusion
close at night as the is too little and a lot of
Oxygen present in the changes in turgidity of glucose will go to waste
air we inhale dissolves the cells on opposite if only diffusion is used.
into the thin layer of surfaces of the petals
moisture on the alveolar causes the petals to
wall before diffusing bend. Active transport is
through the lung cell needed in the ion uptake
into the blood stream to by root hairs. In order to
Importance to living
be transported to all The leaflets of the Mi- maintain the low water
cells
parts of the body. Car- mosa plant fold when potential, ions have to
bon dioxide moves from touched due to changes be absorbed as much
the blood vessels in turgor of cells that hence relying on diffu-
through the lung cell to make up small swellings sion alone won’t be suf-
the alveolar wall and out at the base of the leaf- ficient.
via the respiratory sys- lets.
tem.
Changes in the turgor of
Carbon dioxide diffuses guard cells causes the
into the intercellular air opening and closing of
spaces before dissolving the stomata (refer to
into the moisture to dif- chapter 7)
fuse to the palisade me-
sophyll to be used in
photosynthesis.

6. Plant cells Animal cells
The cell sap has lower potential that The cytoplasm of the animal cell has a
that of the solution outside the living lower water potential than that the out-
cell hence water enters the cell by side of the living cell hence water en-
osmosis. This increases the vacuole’s ters the cell by osmosis. This increases
size and causes the vacuole to push the size of the cell.
the cell contents against the cell wall.
Since it does not have a cell wall, the
Placed in solution of Since the cell wall is strong and rela- cell wall will expand until it bursts due
higher water potential tively inelastic, it opposes the pres- to the high pressure against the cell
sure to prevent more water from surface membrane.
coming in and also prevents over-
expansion of the cell.
As it expands, it becomes turgid but
it doesn’t burst due to the cell wall’s
protection.
The cell sap has higher water poten- The cytoplasm of the animal cell has a
tial that that of the solution outside higher water potential than that of the
the living cell hence water leaves the solution outside the living cell hence
Placed in solution of cell by osmosis. This decreases the water leaves the cell by osmosis. This
lower water potential vacuole’s size and causes the cytop- decreases the cell’s size until eventual-
lasm shrinks away from the cell wall. ly it crenates and little spikes appear on
This causes the cell to be plasmo- the cell surface membrane.
lysed.

7. Chapter 4: Nutrients
Important substance
Characteristics Importance to living organisms
body needs
General formula: CnH2mOm 1. Substrate for respiration to
provide energy for cellular
Divided into three groups: Monosaccharides activities
(glucose, fructose, galactose), Disaccharides
2. Forms supporting structures
(maltose, lactose, sucrose), Polysaccharides
(eg. cellulose cell wall)
(starch, cellulose, glycogen)
3. Converted to amino acids
Glucose + Glucose ⇌ Maltose + Water and fats
Glucose + Fructose ⇌ Sucrose + Water
Glucose + Galactose ⇌ Lactose + Water 4. Needed for formation of
Carbohydrates nucleic acids (eg. DNA)
*Reversible reactions catalysed by enzymes
*This way is condensation reaction, the other 5. Needed to synthesise lubri-
way hydrolytic reaction (occurs in digestive cants (eg. mucus)
system)
6. Needed to synthesise nectar
Excess sugars are stored are polysaccharides as
they are insoluble so they don’t change water
potential, are large molecules so cannot diffuse
out through cell membranes, are easily hydro-
lysed to glucose when needed and are in com-
pact shapes which saves space.
General formula: No fixed proportions, little 1. Source and store of energy
oxygen as compared to hydrogen. Made of C,
H and O. 2. Insulating material prevent-
ing heat loss
Fat molecule + 3Water 
Glycerol + 3Fatty acid molecules 3. Solvent for fat-soluble vi-
tamins
Saturated fats Unsatured fats
Found mostly in an- Found mostly in 4. Essential part of protoplasm
imals vegetables (eg. biphospholipid cell
Fats membrane)
Fatty acid chains are Fatty acid chains are 5. Reduces water loss by se-
straight bent in some places creting an oily substance
over skin, reducing rate of
Solid at rtp Liquid at rtp evaporation
Cholestrol are usually found with polysaturated
fats and this may cause coronary heart disease
or formation of gallstones.

8. General formula: Contains amino group (- 1. Needed in synthesis of new
NH2), acidic group (-COOH) and a side chain protoplasm, for growth and
(R). R can contain sulfur, acidic groups, amino repair of worn-out body
groups and/or hydroxyl groups. cells
2. Needed in the synthesis of
enzymes and some hor-
mones
Proteins
3. Needed for the formation of
antibodies to combat dis-
eases
*A peptide bond is formed between the two
joined amino acids (polypeptides), one water
molecules is formed.
1. Medium for biochemical
reactions in our body
2. Transports digested prod-
ucts, waste products and
hormones around the body
3. Key component of protop-
lasm, lubricants in joints,
digestive juices, blood and
tissue fluid
4. Needed for certain reactions
(eg. hydrolysis in digestion
Water -
and photosynthesis)
5. Component of sweat, when
evaporated, removes latent
heat of vaporisation cooling
us down
6. Maintains turgor pressure in
plants to allow them to be
firm and erect
7. Needed to transport mineral
salts and food substances
from respective parts

9. Substance to be
Test If present, … If absent, …
tested
Add 2 drops of potassium Iodine will turn bluish-
Starch Iodine remains brown.
iodide to test sample. black.
Add equal volumes of Bene-
dict solution (copper (II) sul-
Solution will turn from,
Reducing sugars fate) and test solution into a
with increasing concen-
(eg. glucose, mal- test tube. Place the test tube Solution remains light
tration of reducing sug-
tose, fructose, lac- into a beaker of boiling water blue.
ar, green to yellow to
tose) and remove within 5 mins or
orange to brick-red.
when the solution changes
colour.
Add half the volume of so-
dium hydroxide to the volume
of test sample. Add 1% cop- Solution will turn vio- Solution remains light
Protein
per (II) sulfate solution, drop let. blue.
by drop, shaking after every
drop.
Add ethanol to test solution Cloudy white emulsion
and shake thoroughly. Add will form in the solu- Solution remains co-
Fats
water to the mixture and tion and sinks to the lourless throughout.
shake. bottom.
Small molecules Large molecules
Amino acids Polypeptides form proteins
Glucose Maltose, sucrose, galactose
Glycerol and fatty acids Fats

10. Chapter 5: Enzymes
Characteristic Explanation
Enzymes speed up chemical reactions by lowering the activation
Speed up chemical reactions
energy needed to start the reaction.
Since they remain unchanged after a reaction, they can be used over
Required in very small amounts and over again. This means a small amount of enzyme is able to cata-
lyse a large number of chemical reactions.
Enzymes are highly specific
due to its 3-dimensional
shape. The lock and key hy-
pothesis is able to explain
why.
According to the lock and key
hypothesis, enzyme reaction
Highly specific
depends on the presence of
active sites, depressions on
the surface of an enzyme molecule into which the substrate mole-
cule(s) can fit. When a substrate with a complementary shape to the
shape of the active site binds to the enzyme, an enzyme-substrate
complex is formed and reactions take place at the active sites to con-
vert substrate molecule(s) to product molecule(s). The product mole-
cule(s) separates, leaving the enzyme unchanged and free to recom-
bine with more substrate molecule(s).
Before optimum temperature: After optimum temperature:
Raising the temperature in- Enzymes are made of protein which
creases the kinetic energy of denatures under high temperatures.
the substrates and the en- High temperatures cause the atoms in
Affected by temperature zymes. This causes them to the enzyme to vibrate very violent that
collide more often, increas- they break the hydrogen bonds in the
ing the chance of substrates enzyme causing it to lose its shape
fitting into active sites. The and active site (denaturation). With
rate of formation of the en- this the substrate cannot fit in the en-
zyme-substrate complex in- zyme anymore.
creases leading to a higher
rate of products formed. *Denaturation is irreversible.
Usually, per 10°C increase in
temperature, the rate of reac-
tion doubles.
* Inactiveness is reversible.

11. Affected by pH Changes in pH may cause the acidity or alkalinity to break the hydro-
gen bonds holding the coils in place. This extreme acidity or alkalinity
causes the enzymes to be denatured losing their ability to catalyse the
reactions.
*Denaturation is irreversible.
Enzymes catalyse reactions in the direction where there is a higher
Catalyse reversible reactions
concentration of reactants to the lower concentration of reactants.