Question

Proteins are polymers of $\alpha$-amino acids which are joined to each other by:

• A. Covalent Bond
• B. Peptide Bond
• C. Glycosidic Bond
• D. Coordinate Bond

Hint:

Bond types in biomolecules: Proteins → Peptide bond Carbohydrates → Glycosidic bond Nucleic acids → Phosphodiester bond

Answer 1

The Correct Option is B

Concept: Proteins are formed by the polymerization of $\alpha$-amino acids. The linkage between amino acids occurs through a peptide bond.
Step 1: Understand peptide bond formation. A peptide bond is formed between:

• Carboxyl group (–COOH) of one amino acid
• Amino group (–NH$_2$) of another amino acid

This occurs with the elimination of a water molecule (condensation reaction).
Step 2: Analyze options.
Option (A): Covalent bond → Too general.
Option (B): Peptide bond → Specific linkage in proteins. Correct.
Option (C): Glycosidic bond → Found in carbohydrates.
Option (D): Coordinate bond → Not responsible for protein backbone formation.