Question

Which of the following amino acids \( \text{NH}_2 \text{CH} \text{RCOOH} \) contains a polar R group?

• A. Alanine
• B. Valine
• C. Glycine
• D. Glutamine

Hint:

Amino acids with polar R groups can form hydrogen bonds and are typically hydrophilic. Glutamine contains a polar amide group.

Answer 1

The Correct Option is D

Amino acids have a characteristic side chain (R group) that determines their properties. Polar R groups contain atoms that can form hydrogen bonds, making them hydrophilic. - Alanine has a non-polar R group (methyl group), making it non-polar.
- Valine also has a non-polar R group (isopropyl group), making it non-polar.
- Glycine has a hydrogen atom as its R group, but it is considered non-polar.
- Glutamine, on the other hand, has an amide group \((–C(O)NH_2)\) as its R group, which is polar and hydrophilic. Therefore, the correct answer is option (D).