Read the paragraph given below and answer the question.
Insulin used for diabetes was earlier extracted from slaughtered cattle and pigs. Insulin from an animal source, though caused some patients to develop allergy or other type of reactions. Insulin consists of two short polypeptide chains: chain A and chain B, that are linked together by disulphide bridges. In mammals, including human, insulin is synthesised as a pro-hormone.
Insulin is synthesised as _____________in mammals.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Pro-hormone
Option (1) Pro-hormone — Correct. In mammals, insulin is synthesised as a pro-hormone, which, like a pro-enzyme, must be processed before it becomes fully functional. The pro-hormone has an extra stretch called the C peptide, which is removed during maturation.
Option (2) Pro-enzyme — Incorrect. A pro-enzyme is the inactive form of an enzyme; insulin is a hormone.
Option (4) Disulfide bond — Incorrect. A disulphide bond is a link between the chains.
NCERT Extract:
Genetically Engineered Insulin – “In mammals, including humans, insulin is synthesised as a pro-hormone (like a pro-enzyme, the pro-hormone also needs to be processed before it becomes a fully mature and functional hormone) which contains an extra stretch called the C peptide. This C peptide is not present in the mature insulin and is removed during maturation into insulin.”