Question

Which of the following drugs acts by inhibiting the transcription of DNA to RNA ?

• A. Rifampicin
• B. Nitrofurantoin
• C. Ciprofloxacin
• D. Novobiocin

Answer 1

The Correct Option is A

In the study of pharmacology, it is crucial to understand the mechanisms of action of various drugs. The question at hand requires identifying which drug inhibits the transcription of DNA into RNA. To answer this question, we examine how these drugs interact with bacterial cellular processes:

• Rifampicin: Rifampicin specifically targets bacterial RNA polymerase. By binding to the beta subunit of this enzyme, it blocks the transcription of DNA into messenger RNA (mRNA), effectively inhibiting protein synthesis in bacteria.
• Nitrofurantoin: This antibiotic works by damaging bacterial DNA after being reduced inside the bacterial cell and does not directly inhibit the transcription process from DNA to RNA.
• Ciprofloxacin: A quinolone antibiotic that inhibits DNA gyrase and topoisomerase IV, enzymes critical for DNA replication, but not directly affecting the transcription process.
• Novobiocin: This drug inhibits bacterial DNA gyrase, which is vital for DNA supercoiling, thus affecting DNA replication rather than transcription to RNA.

Conclusively, Rifampicin is the correct answer, as it directly inhibits the RNA polymerase enzyme, thereby preventing the transcription of DNA into RNA.