Question

Which among the following proteins are globular proteins? (i) Keratin (ii) Insulin (iii) Albumin (iv) Myosin Choose the correct answer from the following choices;

• A. (i), (ii) & (iii)
• B. (i) & (iv)
• C. (ii) & (iii)
• D. (i) & (ii)
• E. (iii) & (iv)

Hint:

A simple mnemonic: I-A-G (Insulin, Albumin are Globular).
Fibrous proteins provide structure (hair, muscle), while globular proteins usually handle biological functions (enzymes, hormones).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Based on their molecular shape, proteins are classified into two types:
1. Fibrous proteins: Polypeptide chains run parallel and are held together by hydrogen and disulfide bonds. They are water-insoluble.
2. Globular proteins: Polypeptide chains fold around to give a spherical shape. They are usually water-soluble.

Step 3: Detailed Explanation:
- Keratin: Found in hair, wool, silk. It is a fibrous protein.
- Myosin: Found in muscles. It is a fibrous protein.
- Insulin: Regulates blood sugar. It is a globular protein.
- Albumin: Found in egg white. It is a globular protein.
Therefore, (ii) and (iii) are globular proteins.

Step 4: Final Answer:
The globular proteins are Insulin and Albumin.