Question:
Which of the following mechanisms of antibiotic action is/are NOT correct?
B. Rifampicin: Blocks correct positioning of A-site aminoacyl-tRNA
C. Chloramphenicol: Inhibits EF-Tu function
D. Ciproflaxicin: Inhibits Topoisomerases
E. Puromycin: Causes premature chain termination during translation; mimics 3’ end of aminoacyl‐tRNA in A‐site and acts as
acceptor.
Which of the following mechanisms of antibiotic action is/are NOT correct?
B. Rifampicin: Blocks correct positioning of A-site aminoacyl-tRNA
C. Chloramphenicol: Inhibits EF-Tu function
D. Ciproflaxicin: Inhibits Topoisomerases
E. Puromycin: Causes premature chain termination during translation; mimics 3’ end of aminoacyl‐tRNA in A‐site and acts as acceptor.
B. Rifampicin: Blocks correct positioning of A-site aminoacyl-tRNA
C. Chloramphenicol: Inhibits EF-Tu function
D. Ciproflaxicin: Inhibits Topoisomerases
E. Puromycin: Causes premature chain termination during translation; mimics 3’ end of aminoacyl‐tRNA in A‐site and acts as acceptor.
Show Hint
Rifampicin targets RNA Polymerase; Chloramphenicol targets Peptidyl Transferase.
Updated On: May 14, 2026
- B only
- A, C and D only
- B and C only
- D and E only
Show Solution
Verified By Collegedunia
The Correct Option is C
Solution and Explanation
Step 1: Concept
Antibiotics act by targeting specific bacterial processes like transcription or translation.
Step 2: Meaning
Incorrect descriptions of these mechanisms must be identified.
Step 3: Analysis
- Statement B: Rifampicin actually inhibits DNA-dependent RNA polymerase by binding to the $\beta$-subunit, blocking transcription initiation, not tRNA positioning. - Statement C: Chloramphenicol inhibits the peptidyl transferase activity of the 50S ribosomal subunit, not the EF-Tu function. - Statements A (Tetracycline), D (Ciprofloxacin), and E (Puromycin) are correct descriptions.
Step 4: Conclusion
Statements B and C are incorrect descriptions of antibiotic mechanisms. Final Answer: (C)
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