Question

(i) Differentiate between globular and fibrous proteins. 
(ii) What is meant by denaturation of protein?

• A.
• B.
• C.
• D.

Hint:

Key Points: Fibrous proteins → Structural and insoluble. Globular proteins → Functional and soluble. Denaturation destroys secondary and tertiary structures but not the primary structure.

Answer 1

The Correct Option is A

Concept:
Proteins are macromolecules made up of amino acids linked by peptide bonds. Based on their molecular shape and structure, proteins are mainly classified into fibrous proteins and globular proteins. The biological activity of proteins depends on their specific three-dimensional structure called the native structure.

Step 1: Difference between Fibrous and Globular Proteins.

Fibrous Proteins:
• Shape: Long, thread-like structure
• Solubility: Insoluble in water
• Function: Structural role
• Examples: Keratin, Collagen, Myosin

Globular Proteins:
• Shape: Spherical or globular structure
• Solubility: Usually soluble in water
• Function: Functional or metabolic role
• Examples: Insulin, Albumin, Hemoglobin

Step 2: Denaturation of Proteins.
Denaturation refers to the loss of the natural structure and biological activity of a protein when it is subjected to physical or chemical changes such as:

1. High temperature
2. Change in pH
3. Presence of chemicals or heavy metal ions

During denaturation:

1. The secondary and tertiary structures of the protein are destroyed.
2. The primary structure remains intact.
3. The protein loses its biological activity.

Example: Coagulation of egg white when heated.