Question

The fundamental building block of protein is

• A. Nitrogen
• B. NH₂ group
• C. COOH group
• D. Amino acid

Answer 1

The correct option is D

Amino acid

The correct option is (D):

Explanation of the correct option :

1. Proteins are the abundant structural and functional organic molecules of the living organism.
2. proteins carry many functions in our body like transport of nutrients, fighting against infections and functioning as hormones and enzymes etc.
3. Amino acid is the basic building block of protein.
4. Several amino acid subunits are linked by peptide bonds to form a protein molecule.
5. Proteins are formed through the polymerization of amino acids.

Explanation of the incorrect option :

Option (A):

Nitrogen is a building block of amino acids.

Option (B):

Amines (NH₂ group) are carbon-nitrogen bonds containing molecules.

Option C:

In a carboxyl group (COOH), the carbonyl group ($\mathrm{C}=\mathrm{O}$) is attached to the same carbon atom on which a hydroxyl group (O-H) is present.

Final answer: The fundamental building block of protein is amino acids