Bt Toxin Immunity in Bacteria — NEET Biology

Correct answer: A — A-iii-S, B-ii-R, C-iv-Q, D-i-P

Let's analyze each component: - **A. Pro-insulin:** It is synthesized as a pro-hormone (Column II - iii) that contains an extra stretch called the C-peptide. This C-peptide is removed during maturation into insulin (Column III - S). - **B. Recombinant human insulin:** It is the mature form of insulin, lacking the C-peptide (Column II - ii). In recombinant production, chains A and B are produced separately in E. coli and then combined (Column III - R). - **C. ADA enzyme:** It is crucial for the immune system to function (Column II - iv). In enzyme replacement therapy for ADA deficiency, functional ADA is given periodically by injection (Column III - Q). - **D. Bt toxin:** It exists as an inactive protoxin in bacteria (Column II - i) and the gene for it is expressed in plants to provide pest resistance (Column III - P). Therefore, the correct matching is A-iii-S, B-ii-R, C-iv-Q, D-i-P. Option A correctly matches all components. Option B incorrectly maps pro-insulin characteristic. Option C incorrectly maps several items. Option D incorrectly maps several items. The question tests understanding of the characteristics, maturation, and production/therapeutic application of key biotechnological products as described in NCERT.