GATE 2023 BT – Question 42
Which of the following statement(s) is(are) TRUE about fluoroquinolone drugs?
Practise this question in The GATE Grind →
Show answer and explanation
Correct answer: (A) They contain quinolone ring(s); (C) They bind to bacterial topoisomerase
Explanation
**Fluoroquinolones** (ciprofloxacin, levofloxacin and others) are synthetic antibiotics.
- **A. They contain quinolone ring(s).** True, the name comes from the quinolone core with a fluorine at C-6. ✓
- **B. They inhibit RNA polymerase.** False. RNA polymerase is the target of **rifampicin**.
- **C. They bind to bacterial topoisomerase.** True. They trap **DNA gyrase (topoisomerase II)** and **topoisomerase IV** on the DNA, causing double-strand breaks. ✓
- **D. They bind 23S rRNA in the 50S subunit.** False. This is the site of macrolides, chloramphenicol and linezolid.
Answer **A and C**.