Insulin consists of two polypeptide chains, chain A and B, which are linked together by:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Disulfide bonds
(1) Hydrogen bonds — Incorrect. Hydrogen bonds are weak. They help to hold the shape of a protein but they are not the link between the two chains of insulin.
(2) Peptide bonds — Incorrect. Peptide bonds join one amino acid to the next inside a single chain. They do not join one chain to another.
(3) Glycosidic bonds — Incorrect. Glycosidic bonds join sugar units in carbohydrates. Insulin is a protein.
(4) Disulfide bonds — Correct. Insulin has a short chain A and a short chain B. They are held together by disulphide bridges, which are strong sulphur-to-sulphur links.
Figure 10.3 Maturation of pro-insulin into insulin (simplified)
Note: A similar question was also asked in CUET (UG) 2023 on 31-05-2023 (Slot 3).
NCERT Extract:
Genetically Engineered Insulin – “… Chains A and B were produced separately, extracted and combined by creating disulfide bonds to form human insulin.”
