Q.30 Match the following antibiotics in Group I with their mode of action in Group II
Group I
P. Chloramphenicol
Q. Norfloxacin
R. Puromycin
S. Rifampicin
Group II
1. Binds to DNA gyrase
2. Binds to RNA polymerase
3. Inhibits peptidyl transferase
4. Mimics aminoacyl-tRNA
- (A) P-1, Q-3, R-2, S-4
- (B) P-3, Q-1, R-2, S-4
- (C) P-3, Q-1, R-4, S-2
- (D) P-4, Q-2, R-3, S-1
The correct answer to this antibiotics matching question is option (C): P-3, Q-1, R-4, S-2.
Correct Matching Breakdown
Chloramphenicol (P) inhibits peptidyl transferase on the 50S ribosomal subunit, blocking peptide bond formation during protein synthesis. Norfloxacin (Q) binds to DNA gyrase (topoisomerase II), preventing bacterial DNA unwinding and replication. Puromycin (R) mimics aminoacyl-tRNA, causing premature chain termination by incorporating into nascent polypeptides. Rifampicin (S) binds to the beta subunit of bacterial RNA polymerase, inhibiting transcription initiation.
Option Analysis
Option Matching Correct? Reason (A) P-1, Q-3, R-2, S-4 Chloramphenicol-DNA gyrase; Norfloxacin-peptidyl transferase; Puromycin-RNA polymerase; Rifampicin-aminoacyl-tRNA No Mismatches all; quinolones like Norfloxacin target gyrase, not transferase. (B) P-3, Q-1, R-2, S-4 Chloramphenicol-peptidyl transferase; Norfloxacin-DNA gyrase; Puromycin-RNA polymerase; Rifampicin-aminoacyl-tRNA No Puromycin mimics tRNA (4), Rifampicin binds polymerase (2). (C) P-3, Q-1, R-4, S-2 Chloramphenicol-peptidyl transferase; Norfloxacin-DNA gyrase; Puromycin-aminoacyl-tRNA; Rifampicin-RNA polymerase Yes Matches verified mechanisms from bacterial targets. (D) P-4, Q-2, R-3, S-1 Chloramphenicol-aminoacyl-tRNA; Norfloxacin-RNA polymerase; Puromycin-peptidyl transferase; Rifampicin-DNA gyrase No Chloramphenicol inhibits transferase (3), not tRNA mimicry. This GATE-style question tests antibiotic targets in prokaryotic translation and transcription, key for biotech exams.
