bio assignment

ASSIGNMENT:

MOLECULE of LIFE and
CELL STRUCTURES AND

FUNCTIONS

AFIQ HAIKAL BIN AIZUL FAIZAL
MS2113173286
H1T02A

i)The main types Carbohydrates
of molecules in
Proteins
life

Water DNA and RNA Lipids

Molecules

ii) 3 main classes of Fibrous
protein (based on Protein

structure and Polypeptides chains organised as long
composition) strands/sheets

Eg: Collagen, Stable structures; won't dissolves in
Keratin water

Role in mechanical and structural
functions

Conjugated
proteins

Eg: Glycoprotein, Proteins with non-protein
Lipoprotein, material

HB,Nucleoprotein, (prosthetic group) within
Flavoprotein their structure

Globular
proteins

Eg: Enzymes, Polypeptides folded into spherical
Haemoglobin, shape

Myoglobin Relatively unstable structure; may form
colloids for metabolic and chemical
processes

iii.) A girl with curly hair would like to make her hair straight. Explain how this
can be done in relation with the structure of the hair protein [10 marks].

Hair is made up of keratin
Keratin is a secondary structure of protein
Keratin is made up of alpha helix structure is
connected to hydrogen bonds between polypeptides
During rebonding process, hair keratin was exposed
to the extreme heat
Denaturation of keratin occur; keratin lose its alpha
helix pattern because of the disruption of hydrogen
bonds
Curly hair become staright hair due to protein
denaturation
Denaturation of hair keratin is reversible
The hair will turns curly if the physical aspects of its
environment revert back to normal

iv.) All types of muscle cells consist of filaments containing the proteins actin and myosin. Differentiate the three types of muscle cells in

terms of their structure [5 marks].

1.Smooth Muscle 2. Striated muscle 3. Cardiac muscle

- A single cell, a central nucleus •cylindrical, very long muscles called •Striated
- elongated spindle-shaped, •Has elongated, cylindrical
pointed ends fibers
- unstriated (no cross-striations branched fibers that interconnect
- lining the walls of: •contain many protein fibers;
• digestive tract •myofibrils via intercalated disc – relay signals
•has many nuclei-(multinucleated)
form cell to cell
located below
•Located in the walls of the heart
•the plasma membrane striated

• urinary bladder muscle with myofibrils
• uterus
•the arrangement of filaments gives

• blood vessels (arteries & light & dark bands
veins)
•attached to the skeleton