BIO FLIPBOOK - MOLECULES OF LIFE & CELL STRUCTURES AND FUNCTIONS

Biology NAME
SET D
Sarah binti Razali

MATRIC NUMBER

MS2213104545

PRACTICUM

H4T02A

LECTURER’S NAME

Puan Nor Zaity Binti Bakri

1. State main types of molecules of life . ( 5 marks )

● Water
● Carbohydrates
● Lipids
● Proteins
● DNA and RNA Molecules

2. Classify proteins into three main classes
according to their structure and composition .

( 15 marks )

Classification of Fibrous protein Globular protein Conjugated
protein protein
• Linear shaped • Spherical
Structure • Insoluble in shaped • Linear and
spherical
water • Soluble in shaped
water

Composition • composed of • contain one or • Contain
Example only amino
acid more non- protein q\with

amino acid non-protein

components material

• Collagen • Enzymes • Glycoprotein
• Keratin • Haemoglobin • Lipoprotein

3. 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 )

● Straightening consists of temporary or permanent breaks in the chemical
bonds that maintain the structure of keratin protein in its original rigid
form .

● Keratin that is found in the hair consist of long molecular chain of amino
acids

● It coils to form alpha helix
● There are three main types of interchain interactions that occur between

molecules of keratin of hair fiber :-
- Disulphide bond , hydrogen bond and coulomb bond
● Hydrogen bonds are the most numerous in hair fibers and are essential
for the stability of the alpha helix of structure of keratins
● However , the bonds are weak and can easily broken by water and heat
● When straightening the hair , the hair has to be pre-wetted so that the
bonds are temporarily disrupted , thus make it easier to utilize the hair’s
flexible hydrogen bonding structure to reshape it .

Structure of the hair fibre
Types of interactions

4. 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 ( 15 marks )

Types of muscle Cardiac Muscle Skeletal Muscle Smooth Muscle
Shape of muscle fiber
Branched muscle fiber Cylindrical Cylindrical Fusiform
Yes No No
Location
The heart Attached to bones Internal organs and
Nuclei Single , located Many , located skin
Striations peripherally
centrally Yes Single , located
Cells connected by Yes centrally
-
Intercalated Discs No

Gap junctions

Diagram