Insulin Structure: Disulphide Bonds — NEET Biology
✅ Asked in NEET 2020Which of the following statements is not correct? (NEET 2020)
Which of the following statements is not correct? (NEET 2020)
The two polypeptides of human insulin are linked together by (NEET 2016 Phase 1)
Answer & NCERT explanation
Correct answer: A — The functional insulin has A and B chains linked together by hydrogen bonds.
Statement A is incorrect - functional insulin has A and B chains linked by disulphide bridges, not hydrogen bonds. Two interchain and one intrachain disulphide bonds maintain insulin's structure. Other statements are correct: insulin is produced in E.coli through genetic engineering, synthesized as proinsulin in humans, and proinsulin contains C-peptide connecting A and B chains.
Read more NCERT concept on the PYQ
Insulin used for diabetes was earlier extracted from pancreas of slaughtered cattle and pigs. Insulin from an animal source, though caused some patients to develop allergy or other types of reactions to the foreign protein. Insulin consists of two short polypeptide chains: chain A and chain B, that are linked together by disulphide bridges.
NTA tests whether students know that insulin's two polypeptide chains (A and B) are held together by disulphide bridges, NOT hydrogen bonds. Many students confuse disulphide bonds with weaker hydrogen bonds or think chains are merely connected by peptide bonds. The key trap: NTA asks "what links insulin chains?" or "which bond type maintains insulin structure?" and offers hydrogen bonds as a distractor. Remember: disulphide bonds are covalent cross-links between cysteine residues on different chains, making them strong and stable—essential for insulin's biological activity. This concept appears because understanding protein quaternary structure through different bond types is fundamental to biotechnology applications.
What does NCERT say about Insulin used for diabetes?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
88/90MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.