Sample 1Medium
A diagram of insulin maturation shows a single polypeptide, proinsulin, with three segments labelled A, B and C. Segment C is cut away, and the remaining two chains, held together by disulphide bridges, form mature insulin. Which statement is correct?
- A
The removed segment is the C-peptide, and Eli Lilly made chains A and B separately in E. coli and joined them by disulphide bonds
- B
The removed segment is the A-peptide, and mature insulin is made of chains B and C
- C
Mature insulin is a single chain because the C-peptide links A and B
- D
The removed segment is the C-peptide, and recombinant insulin is made by expressing proinsulin in cattle
Show the answer
The answer is A.Insulin is made as a prohormone with an extra C-peptide, which is removed during maturation, leaving chains A and B linked by disulphide bridges. In 1983 Eli Lilly produced the A and B chains separately in E. coli and combined them by creating disulphide bonds.
- B.
Chains A and B form mature insulin; the extra C-peptide is removed.
- C.
Mature insulin has two chains linked by disulphide bridges, with C removed.
- D.
Eli Lilly expressed the A and B chains in E. coli plasmids, not in cattle.
NCERT: Class 12 Biology, Chapter 10, 10.2
Sample 2NEET level
Match List I with List II. List I: A. Human insulin by Eli Lilly (1983) B. ADA deficiency C. ELISA D. PCR List II: I. Detection of very low amounts of a pathogen's nucleic acid by amplification II. Gene therapy using lymphocytes and a retroviral vector III. A and B chains produced separately in E. coli and joined by disulphide bonds IV. Diagnosis based on antigen-antibody interaction Choose the correct answer.
- A
A-III, B-IV, C-II, D-I
- B
A-II, B-III, C-IV, D-I
- C
A-III, B-II, C-IV, D-I
- D
A-III, B-II, C-I, D-IV
Show the answer
The answer is C.Eli Lilly prepared DNA for the A and B chains of insulin, produced them in E. coli and combined them by disulphide bonds. ADA deficiency was treated by gene therapy in which lymphocytes received functional ADA cDNA through a retroviral vector; ELISA works on antigen-antibody interaction, and PCR detects pathogens by amplifying their nucleic acid.
- A.
Swaps ADA deficiency and ELISA.
- B.
Swaps insulin production and ADA gene therapy.
- D.
Swaps ELISA and PCR: ELISA rests on antigen-antibody binding, PCR on amplification.
NCERT: Class 12 Biology, Chapter 10 (Biotechnology and its Applications), Biotechnological applications in medicine