Q.77 Match the antimicrobial agents in group I with their category/mode of action in group II
| Group I | Group II |
|---|---|
| (i) Fluoroquinolones | (p) β-lactam antibiotic |
| (ii) Tetracycline | (q) Inhibition of nucleic acid synthesis |
| (iii) Amphotericin B | (r) Inhibition of protein synthesis |
| (iv) Amoxicillin1 | (s) Antifungal agent |
Options:
- (A) (i)-(p), (ii)-(q), (iii)-(r), (iv)-(s)
- (B) (i)-(q), (ii)-(r), (iii)-(s), (iv)-(p)
- (C) (i)-(r), (ii)-(s), (iii)-(p), (iv)-(q)
- (D) (i)-(s), (ii)-(p), (iii)-(q), (iv)-(r)
The correct answer is option (B): (i)-(q), (ii)-(r), (iii)-(s), (iv)-(p). Fluoroquinolones inhibit nucleic acid synthesis, tetracycline inhibits protein synthesis, Amphotericin B is an antifungal agent, and Amoxicillin is a β-lactam antibiotic.
Agent Mechanisms
Fluoroquinolones target bacterial DNA gyrase and topoisomerase IV, enzymes essential for DNA replication and repair, blocking nucleic acid synthesis. Tetracycline binds to the 30S ribosomal subunit, preventing aminoacyl-tRNA attachment and halting protein synthesis. Amphotericin B binds ergosterol in fungal membranes, forming pores that leak ions and cause cell death, classifying it as an antifungal. Amoxicillin, a penicillin derivative, inhibits peptidoglycan cross-linking in bacterial cell walls via penicillin-binding proteins, marking it as a β-lactam antibiotic.
Option Analysis
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(A) (i)-(p), (ii)-(q), (iii)-(r), (iv)-(s): Incorrect. Fluoroquinolones do not inhibit cell walls (p); tetracyclines target proteins, not nucleic acids (q); Amphotericin B is antifungal, not protein inhibitor (r).
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(B) (i)-(q), (ii)-(r), (iii)-(s), (iv)-(p): Correct. Matches all mechanisms precisely.
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(C) (i)-(r), (ii)-(s), (iii)-(p), (iv)-(q): Incorrect. Fluoroquinolones spare proteins (r); tetracyclines are not antifungal (s); Amphotericin B ignores bacterial walls (p).
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(D) (i)-(s), (ii)-(p), (iii)-(q), (iv)-(r): Incorrect. Fluoroquinolones are antibacterial, not antifungal (s); tetracyclines avoid cell walls (p).
Fluoroquinolones, Tetracycline, Amphotericin B, and Amoxicillin represent key antimicrobial agents matching modes of action critical for CSIR NET Life Sciences preparation. This guide breaks down their categories—nucleic acid synthesis inhibition, protein synthesis inhibition, antifungal action, and β-lactam antibiotics—for exam success.
Key Mechanisms
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Fluoroquinolones (q) Inhibition of nucleic acid synthesis: These bind DNA gyrase/topoisomerase IV, halting bacterial DNA replication.
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Tetracycline (r) Inhibition of protein synthesis: Binds 30S ribosome, blocking tRNA and translation.
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Amphotericin B (s) Antifungal agent: Targets ergosterol, disrupting fungal membranes.
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Amoxicillin (p) β-lactam antibiotic: Blocks cell wall peptidoglycan via PBPs.
Exam Relevance
Ideal for CSIR NET matching questions on antimicrobial agents matching, these distinctions aid in options like (i)-(q), (ii)-(r), (iii)-(s), (iv)-(p). Practice reinforces pharmacology for competitive biology exams.
