Question

Functional groups present in amino acids are :

• A. \( \mathrm{-NH_2} \) and \( \mathrm{-OH} \)
• B. \( \mathrm{-OH} \) and \( \mathrm{-COOH} \)
• C. \( \mathrm{-COOH} \) and \( \mathrm{-NH_2} \)
• D. \( \mathrm{-NH_2} \) and \( \mathrm{-SO_3H} \)

Hint:

Every amino acid carries a basic amino group and an acidic carboxyl group, so pick the option with -COOH and -NH2.

Answer 1

The Correct Option is C

Step 1: Recall what an amino acid is:
An amino acid is an organic compound with two kinds of groups in the same molecule.
One is a basic amino group. The other is an acidic carboxyl group.
The general formula is \( \mathrm{H_2N-CHR-COOH} \), where R is the side chain.

Step 2: Name the two groups:
The amino group is \( \mathrm{-NH_2} \). It makes the molecule basic.
The carboxyl group is \( \mathrm{-COOH} \). It makes the molecule acidic.
In the alpha-amino acids of proteins, both groups sit on the same carbon atom.

Step 3: Check option (A).
It lists \( \mathrm{-NH_2} \) and \( \mathrm{-OH} \). A hydroxyl group alone is not the acidic part of an amino acid, so (A) is wrong.

Step 4: Check option (B).
It lists \( \mathrm{-OH} \) and \( \mathrm{-COOH} \). It has no amino group, so it cannot be an amino acid. (B) is wrong.

Step 5: Check option (D).
It lists \( \mathrm{-NH_2} \) and \( \mathrm{-SO_3H} \). The sulphonic acid group is not found in the standard amino acids, so (D) is wrong.

Final Answer:
Amino acids contain the carboxyl group and the amino group. This is option (C). \[ \boxed{\mathrm{-COOH\ and\ -NH_2}} \]