SB015_NURUL FATHIHAH

ASSIGNMENT SB015 2022/2023

MOLECULE OF
LIFE &
CELL STRUCTURE
AND FUNCTIONS

SET C
CREATED BY:

NAME: NURUL FATHIHAH BINTI JAAFAR
MACTRIC'S NUMBER: MS2113172828
PRACTICUM: H6P02B

WATER LIPID

CARBOHYDRATE

MAIN TYPES OF MOLECULE OF LIFE

DNA AND
MRNA
MOLECULES

PROTEIN

MAIN TYPES OF
LIPIDS

FAT AND OIL
PHOSPHOLIPID

STEROID

CHARACTERISTIC OF

Triglyceride

Consist of 1 glycerol and 3 fatty acid
Glycerol is a type of alcohol that containing 3 carbon atoms
and 3 hydroxyl groups
fatty acid consist of a long hydrocarbon chain and carboxyl
group
insoluble in water due to the hyd
rocarbon chain of fatty acid that non-polar and
hydrophobic
there are 2 types of fatty acid which are saturated fatty
acid and unsaturated fatty acid

Saturated fat Unsaturated fat

No double bondbetween carbon Has 1 or more double bonds
atoms in a chain between carbon atoms in a chain

has as many as possible hydrogen less 1 hydrogen atom at the
atoms are bonded to the carbon carbon- carbon double bond

has high melting point has low melting point
exist in solid form at room exist in liquid form at room
temperature temperature

CHARACTERISTIC OF

Phospholipid

The major component of cell membranes
It consist of 1 glycerol and 2 fatty acid.
The 3rd hydroxyl group of glycerol is linked with
phosphate group that has negative charge.
Amphipathic molecules that has a head that
hydrophilic and the tail that hydrophobic due to the
charge additional molecule that usually attached to
the phosphate group.
Small molecules can pass through it through simple
diffusion. Example of the molecules is CO2, O2 and
some lipid substances.

CHARACTERISTIC OF

Steroid

A steroid is a biologically active organic compound
with four rings arranged in a specific molecular
configuration.
Steroids have two principal biological functions: as
important components of cell membranes which alter
membrane fluidity; and as signaling molecules.
Characterized by a carbon skeleton consisting of 4
fused ring and form 17 carbon atoms.
Functional groups attached to the rings determine
the types of steroids
Example: the functional group for testosterone is
ketone and hydroxyl group

The structure of
plasma membrane



The name of the model is Fluid Mosaic Model that

proposed by S.J Singer and G.L Nicolson (1972)
* >“membranes are composed of 2 layer of phospholipid
with globular protein embedded in the bilayer.
* >Fluid means the phospholipids and the proteins can

move laterally
*>Mosaic means proteins are embedded in the

phospholipid bilayer.



Shows the amphipathic characteristic of phospholipids and
proteins.

Phospholipid bilayer has polar region and non polar region
*>Polar region: hydrophilic

*>Non polar region: hydrophobic

Phospholipid Proteins

Component of
plasma membrane

Cholesterol Carbohydrate

Phospholipid

form structural framework of the membrane
The polar heads point upward and attracted to
water surrounding
The non-polar tails facing inward

protein

There are 2types of proteins which are Integral
proteins and peripheral protein
Integral proteins that are partially embedded or fully
embedded
Example: carrier proteins, channel proteins, protein
ungated channels and protein gated channel

cholesterol

Located between phospholipids bilayer
Function: stabilizes the membrane structure
by restricting the movement of the
phospholipids.

carbohydrate

Found on the external surface of the plasma
membrane
Carbohydrate + proteins -> glycoproteins
Carbohydrate + lipids -> glycolipids

The way the lipids control
the fluidity of membrane

plasma

Membrane fluidity is affected by fatty acids. More
specifically, whether the fatty acids are saturated
or unsaturated has an effect on membrane fluidity.
Saturated fatty acids have no double bonds in the
hydrocarbon chain, and the maximum amount of

hydrogen.
The absence of double bonds decreases fluidity,
making the membrane very strong and stacked

tightly.
Unsaturated fatty acids have at least one double
bond, creating a "kink" in the chain. The double
bond increases fluidity. Membrane fluidity is also

affected by cholesterol.
Cholesterol can make the cell membrane fluid as

well as rigid.
At moderately warm temperatures, cholesterol
molecules reduce membrane fluidity by preventing

free movement of phospholipids molecules.
At cool temperatures, cholesterol molecules prevent

close packing phospholipids and slow down
solidification