Select the incorrect statement about the insulin hormone produced by rDNA technique.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Two chains were extracted and combined with C chain.
Insulin has two short polypeptide chains, chain A and chain B, joined by disulphide bonds. In humans it is first made as a pro-hormone with an extra stretch called the C peptide. The C peptide is removed when the hormone matures, so it is not part of mature insulin.
(1) Two DNA sequences corresponding to A and B chains of insulin were prepared and introduced in E. coli. — True statement. This is what Eli Lilly did, using plasmids of E. coli.
(2) Chains A and B were produced separately. — True statement. They were made separately, then extracted and joined by disulphide bonds.
(3) Two chains were extracted and combined with C chain. — False statement. The two chains are combined with each other by disulphide bonds. The C peptide is not part of mature insulin.
(4) In 1983, Eli Lilly, an American company, prepared the first human insulin. — True statement. In 1983, Eli Lilly prepared the DNA sequences for the two chains of human insulin.
NCERT Extract:
Genetically Engineered Insulin – …
