FLIPBOOK NURIN NABILAH BINTI SHAHARUDDIN (K1T01A)(SET D)

NAME : NURIN NABILAH BINTI Biology SB015
SHAHARUDDIN
MATRIC NUMBER : MS2113172967 MOLECULES OF
CLASS : K1T01A LIFE
LECTURER'S NAME : PUAN &
HABIBAH BINTI MOHAMAD REJAB CELL

STRUCTURE AND
FUNCTIONS

Table of BIOLOGI SB015
contents Types of molecules of life
Three classes of proteins
MOLECULES OF LIFE
& Question
Difference types of muscle cells
CELL STRUCTURE AND FUNCTIONS

Three types
of

molecules
of life

i. The main types of molecules of life are
water, carbohydrates, lipids, proteins
and DNA and RNA molecules

Question#2 :

ii. The three main classes of proteins are fibrous proteins,
globular proteins and conjugated proteins. Fibrous proteins
are polypeptide chains organised as long strands or sheets.
It is stable structure which won’t dissolve in water. Fibrous
proteins play role in mechanical and structural functions.
The example are collagen and keratin.

The second classes of proteins is globular proteins.
Globular proteins are polypeptides that are folded into
spherical shape. It is relatively unstable structure, may
form colloids in water. Moreover, globular proteins
generally for metabolic and chemical processes. The
example are enzymes, haemoglobin, and myoglobin.

The third class is conjugated proteins. Conjugated
proteins are protein with non-protein material that is
prosthetic group within their structure. The example are
glycoprotein, lipoprotein, Hb, nucleoprotein, flavoprotein.

Qyestion#3:

STRUCTURE OF HAIR
PROTEIN

The primary component of the hair fiber is keratin.
Because of its specific conformation and chemical bonds, keratin is
responsible for hair stiffness, strength, and insolubility.
Moreover, keratin has secondary structure level protein that coiled due to
hydrogen bond.
This can be done with rebonding techniques.
The process occurs is denaturation.
Curly hair made straight by denaturation. When introduced to high heat,
high temperature cause denaturation by breaking the hydrogen bond.
Thuseratin loses its original conformation.
An unfolded protein can be restored to its correct folding and regains its
biological activity.
If the denatured protein remains in aqueous environment and denaturing
agent is removed, it may renature when chemical and physical aspects of
its environment revert back to normal.
When a chemical relaxer and heat applied to a curly hair, the protein
present inside your hair get denature.
Due to this denaturation of protein in the hair, the hair are soft and flexible
which can be converted into any direction and different styles can be done.
Basically, water breaks the hydrogen bonds of the keratin molecules in your
hair. A chemical, usually formaldehyde, then crosslinks the new design of
your hair structure in a pin-straight alignment.
The result is hair that looks even straighter than naturally straight hair.

Question #4:

three types of muscle cells
in terms of their structure

The three main types of muscle include skeletal muscle, smooth muscle and cardiac muscle.
Smooth muscle has a central nucleus.
It has also unbranched spindle-shaped, pointed ends and unstriated at lining walls of digestive tracts, urinary bladder, uterus
and blood vessels.

Secondly, skeletal muscle. Skeletal or striated muscle is a cylindrical, very long muscles called fibres, striated and unbranched.
It contains many protein fibres that is myofibrils and has many nuclei located below the plasma membrane.
Structure of muscle cells are sarcolemma that is plasma membrane and sarcoplasm that is the cytoplasm contains many
mitochondria.
Striated muscle are with myofibrils. Furthermore, each cell divided into a functional unit known as sarcomere and consist of
filaments actin and myosin.
The arrangement of filaments gives light and dark bands. Next, striated muscle are attached to the skeleton (bones).

The third one is cardiac muscle. It is striated, has elongated, cylindrical branched fibres that interconnect via intercalated
disc.
It is located in the walls of the heart.
However, cardiac muscle fibers are shorter than skeletal muscle fibers and usually contain only one nucleus, which is located
in the central region of the cell.