ADELLYN WOO PUI KUAN_H8T04B_FINAL

BIO FLIPBOOK BIOLOGY SB015 ASSIGNMENT

Molecules of Life

&

Cell Structures and Functions

Name: Adellyn Woo Pui Kuan
Matric number: MS2213208507
Practicum: H8T04B
Set responsible: Set D

2022.09.02

BIO FLIPBOOK https://www.ypppt.com/

1 main types of molecules of life

2 3 main classes of protein CONTENTS
3 Explanation of formation of straighten

hair from curly

4 Differentiate 3 types of muscle cells

State the main types of molecules of life

BIO FLIPBOOK

Water Carbohydrate Lipids

Consists of 1 oxygen Composed of carbon, Consists of carbon,
atom and 2 hydrogen hydrogen & oxygen atoms hydrogen and
in the proportion of 1 : 2 : 1
atoms oxygen atoms which
DNA & RNA the proportion of
Protein

Always composed of molecule oxygen is less than
carbon, hydrogen,
Consists of phosphate carbohydrates

oxygen & nitrogen; & group, pentose sugar

sometimes sulphur and nitrogenous base

BIO FLIPBOOK Main classes of protein

❖Fibrous Protein
❖Globular protein
❖Conjugated protein

click

Classify proteins into three main classes according to their
structure and compositions (15m)

BIO FLIPBOOK Fibrous protein Globular protein Conjugated protein

Polypeptide chains Polypeptide folded into Formation of proteins and non-
organized as long strands spherical shape protein material within their
or have a sheet like structure
structure Relatively unstable structure
bounded by covalent bonds
Stable structures may form colloids in water
Non-protein material (lipid,
will not dissolve in water Generally for metabolic & carbohydrate) is called prosthetic
chemical processes group
Role in mechanical &
structural functions Exp: enzymes, haemoglobin functions in interaction with other
and myoglobin (non-polypeptide) chemical groups
Example: keratin, collagen, attached by covalent bonding or
elastin and fibrin weak interactions.

Exp: Glycoprotein, lipoprotein,
nucleoprotein, flavoprotein,
phosphoprotein

BIO FLIPBOOK A girl with curly hair would like to make her hair straight. Explain how this

can be done in relation with the structure of hair protein (10m)

What do you know about hair??

o Our hair protein is called keratin.
o Keratin is a protein that helps form hair, nails and the

epidermis and maintain health and strength of hair and
skin.
o It is located at the hair, nail, epidermis, glands and organs.
o Keratin can exist as alpha-keratins and beta-keratins
according of its polypeptide chains.
o Alpha-keratins are mostly fibrous, and their structure
looks like the thread of a screw (helical).
o Beta-keratins are sheets of polypeptide chains that
extend in the same directions and never overlap (parallel).
This construction gives beta-keratins their tough, rigid
structure.
o The structure of keratin consists of many different
proteins, including various types of keratins, keratin-
associated proteins (KFAPs) and enzymes drawn from
animal tissues.

BIO FLIPBOOK A girl with curly hair would like to make her hair straight. Explain how this

can be done in relation with the structure of hair protein (10m)

Temporary straightening of hair
• Can be applied with the physicochemical techniques such

as dryer, flat iron and the old hot comb
• Hair has to be pre-wetted, to break the physical hydrogen

bonds of keratin which is located in the cortex of hair
follicle.
• High temperature of air from the dryer will cause
denaturation of keratin and hence disturb the hydrogen
bond
• Keratin loses its original conformation and its ability to
function.
• Thus, the strands of keratin is straighten.

BIO FLIPBOOK A girl with curly hair would like to make her hair straight. Explain how this

can be done in relation with the structure of hair protein (10m)

Permanent straightening of hair
• It is affected by breaking and reforming the chemical side bonds in

the hair.
• Disulphide bonds in the hair are broken through a process called

‘reduction’
• In the existing or untreated hair, the disulphide bonds join one

sulphur atom in the polypeptide chain to another sulphur atom on
another polypeptide chain
• Reducing agents called thiol compounds add a hydrogen atom to
each of these sulphur atoms in the disulphide bonds to break them.
• The broken disulphide bonds are then neutralized to remove the
hydrogen atoms using the most common
neutralizer hydrogen peroxide.
• This process removes the hydrogen atoms and reforms the
disulphide bonds, and is called oxidation,
• The removal of the hydrogen atoms from the sulfur atoms forces
them to reform their disulphide bonds in the new shape
permanently.

BIO FLIPBOOK All types of muscle cells consist of filaments containing the
proteins actin and myosin. Differentiate the 3 types of muscle cells

in terms of their structure (5m)

Smooth muscle Straited muscle Cardiac muscle

A single cell, one central has many nuclei Has 2 controlling nuclei
nucleus (multinucleated) located
below the plasma membrane Elongated and cylindrical in
elongated spindle-shaped, shape
pointed ends cylindrical, very long muscles
called fibers Striated
unstraited
Straited Involuntary activities:
Responsible for Involuntary contraction of the muscle is
(unconscious) activities: Responsible for voluntary for pumping of blood
Peristalsis in digestive tracts activities.: through the heart
Movement of the skeleton &
Does not have branch organs Has branched fibers that
interconnect via intercalated
Does not have branch disc – relay signals form cell
to cell

BIO FLIPBOOK Thanks for watching！

2022.09.02