Question

In which of the following amino acids -OH group is present?

• A) Lysine, B) Serine
• A) Lysine, C) Tyrosine
• B) Serine, C) Tyrosine
• B) Serine, D) Valine

Hint:

- Amino acids with hydroxyl groups, like Serine and Tyrosine, are often involved in hydrogen bonding and enzyme catalysis due to the presence of the –OH group.

Answer 1

The Correct Option is C

This question asks which amino acids from the list contain an –OH group (hydroxyl group) in their side chains. Here’s the analysis of each amino acid: 1. Lysine (A):
Lysine contains an amino group (\(-\mathrm{NH_2}\)) at the end of its side chain, but does not have a hydroxyl group (\(-\mathrm{OH}\)) in its side chain. Therefore, lysine does not contain an –OH group.
2. Serine (B):
Serine contains a hydroxymethyl group (\(-\mathrm{CH_2OH}\)) in its side chain. This hydroxymethyl group contains a hydroxyl (\(-\mathrm{OH}\)) group, making serine one of the amino acids with an –OH group. 3. Tyrosine (C):
- Tyrosine contains a phenolic group (-OH attached to a benzene ring) in its side chain. This is another amino acid that contains a hydroxyl group, specifically attached to a benzene ring, which is characteristic of tyrosine. 4. Valine (D):
- Valine is a branched-chain amino acid with a nonpolar, hydrophobic side chain. It does not contain a hydroxyl group. From this, we can conclude that Serine (B) and Tyrosine (C) are the amino acids that contain an –OH group in their side chains. Thus, the correct answer is B) Serine and C) Tyrosine (Option 3).