Question

Consider the following amino acids:
•[(i)] Lysine
•[(ii)] Glutamine
•[(iii)] Arginine
•[(iv)] Leucine
•[(v)] Serine
•[(vi)] Proline
•[(vii)] Valine Which of the given amino acids are basic in nature?

• A. (i) and (iii)
• B. (i), (ii) and (iv)
• C. (iii) and (vii)
• D. (iii), (v) and (vi)

Hint:

Basic amino acids: Lysine, Arginine, Histidine.
Acidic amino acids: Aspartic acid, Glutamic acid.

Answer 1

The Correct Option is A

Concept: Amino acids are classified based on the nature of their side chain. Basic amino acids contain extra amino groups or nitrogen-rich groups that can accept protons.

Step 1: Identify basic amino acids
•Lysine → contains extra \( -NH_2 \) group → basic
•Arginine → contains guanidine group → strongly basic

Step 2: Check remaining amino acids
•Glutamine → neutral (amide group)
•Leucine, Valine → non-polar (neutral)
•Serine → polar but neutral
•Proline → neutral Final: \[ {\text{Basic amino acids = Lysine and Arginine}} \]