Which class targets DNA replication by inhibiting DNA gyrase/topoisomerase?

Which class targets DNA replication by inhibiting DNA gyrase/topoisomerase?

• A. Folate synthesis inhibitors
• B. Aminoglycosides
• C. Penicillins
• D. Fluoroquinolones

Answer: (D)

The drugs in this class act by blocking the enzymes that manage DNA topology during replication, specifically DNA gyrase and topoisomerase IV. By inhibiting these enzymes, they prevent the relaxation, supercoiling, and separation of DNA strands that replication requires. The result is DNA breakage and faulty chromosome separation, which is lethal to the bacterium. This mechanism directly targets DNA replication, making this class the best fit. In contrast, other classes work on different targets: blocking folate synthesis impairs nucleotide production, aminoglycosides disrupt the ribosome to stop protein synthesis, and penicillins inhibit cell wall formation.

The drugs in this class act by blocking the enzymes that manage DNA topology during replication, specifically DNA gyrase and topoisomerase IV. By inhibiting these enzymes, they prevent the relaxation, supercoiling, and separation of DNA strands that replication requires. The result is DNA breakage and faulty chromosome separation, which is lethal to the bacterium. This mechanism directly targets DNA replication, making this class the best fit.

In contrast, other classes work on different targets: blocking folate synthesis impairs nucleotide production, aminoglycosides disrupt the ribosome to stop protein synthesis, and penicillins inhibit cell wall formation.