Question

Match LIST-I with LIST-II

Choose the correct answer from the options given below:

• A. A-I, B-II, C-III, D-IV
• B. A-I, B-III, C-II, D-IV
• C. A-I, B-II, C-IV, D-III
• D. A-III, B-IV, C-I, D-II

Hint:

Categorize antibiotics by target: Cell Wall (\(\beta\)-lactams like Cephalosporins), DNA Synthesis (Quinolones like Nalidixic acid), Protein Synthesis (Macrolides like Erythromycin target 50S), and Metabolic Pathways (Isoniazid targets mycolic acid synthesis).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
This question requires matching different classes of antimicrobial agents with their specific mechanisms of action against microbes.
Step 2: Detailed Explanation:
Let's match each agent in LIST-I with its mode of action from LIST-II:


A. Cephalosporins: Cephalosporins are \(\beta\)-lactam antibiotics, similar to penicillin. Their primary mechanism is to inhibit the transpeptidase enzymes that catalyze the final cross-linking step in peptidoglycan synthesis. This matches I. Act by inhibition of biosynthesis of the peptidoglycan cell-wall structure.

B. Nalidixic acid: This is a quinolone antibiotic. Quinolones work by inhibiting DNA gyrase (a type II topoisomerase), an enzyme essential for DNA replication, repair, and recombination in bacteria. This matches II. Inhibition of DNA synthesis in gram-negative bacteria.

C. Isoniazid: This is a primary drug used to treat tuberculosis. It works by inhibiting the synthesis of mycolic acids, which are unique and essential components of the Mycobacterium cell wall. This mechanism effectively blocks the use of pyridoxal phosphate (derived from pyridoxine) and NAD (from nicotinamide) in mycolic acid synthesis. This matches IV. Blocking pyridoxin and nicotinamide - catalyzed reactions in the microbial cell.

D. Erythromycin: This is a macrolide antibiotic. It functions by binding to the 50S subunit of the bacterial ribosome, blocking the exit tunnel and thereby inhibiting the translocation step of protein synthesis. This matches III. Inhibits protein synthesis as a result of binding on the 50S subunit ribosome.

Step 3: Final Answer:
The correct matching is A-I, B-II, C-IV, D-III. This corresponds to option (C).