Question

Identify the amino acids given below and select the correct option:

• A. A - Glycine, B - Serine, C - Alanine
• B. A - Alanine, B - Serine, C - Glycine
• C. A - Alanine, B - Glycine, C - Serine
• D. A - Serine, B - Alanine, C - Glycine

Hint:

Remember these common amino acid side chains:
Glycine → $R = H$ (simplest amino acid)
Alanine → $R = CH_3$
Serine → $R = CH_2OH$
Glycine is the only amino acid that is achiral.

Answer 1

The Correct Option is C

Step 1: Understanding the basic concept:
Amino acids have a general structure given by $R-CH(NH_2)-COOH$, where $-NH_2$ is the amino group, $-COOH$ is the carboxylic acid group, and $R$ is the side chain.
The identity of an amino acid depends on the nature of this $R$ group.

Step 2: Identifying the R-groups in each structure:
Let us examine the side chain (R group) in each structure:

• Structure A: The R group is $-CH_3$, which is a methyl group. This corresponds to Alanine.
  
• Structure B: The R group is $-H$, which is the simplest possible side chain. This represents Glycine.
  
• Structure C: The R group is $-CH_2OH$, known as a hydroxymethyl group. This corresponds to Serine.
  

Step 3: Matching with the given options:
Thus, the correct identification is:
A = Alanine, B = Glycine, C = Serine
This matches with Option (C).

Step 4: Final conclusion:
Therefore, the correct answer is Option (C).