Topoisomerase inhibitors function by inhibiting topoisomerases, which normally perform what role?

Topoisomerase inhibitors function by inhibiting topoisomerases, which normally perform what role?

• A. Cutting and pasting RNA
• B. Breaking and repairing DNA to allow flexibility during replication
• C. Stabilizing microtubules
• D. Methylating DNA

Answer: (B)

Topoisomerases temporarily cut DNA to relieve torsional strain that builds up as the helix unwinds during replication and transcription. They then reseal the breaks, allowing the DNA strands to pass through each other and return to a relaxed state. This break-and-reseal mechanism enables the DNA to unkink and untangle, keeping replication and transcription running smoothly. Inhibitors block the resealing step, causing DNA breaks that are particularly lethal to dividing cells. The other options describe processes that topoisomerases do not perform: RNA cutting/pasting, stabilizing microtubules, or DNA methylation.

Topoisomerases temporarily cut DNA to relieve torsional strain that builds up as the helix unwinds during replication and transcription. They then reseal the breaks, allowing the DNA strands to pass through each other and return to a relaxed state. This break-and-reseal mechanism enables the DNA to unkink and untangle, keeping replication and transcription running smoothly. Inhibitors block the resealing step, causing DNA breaks that are particularly lethal to dividing cells. The other options describe processes that topoisomerases do not perform: RNA cutting/pasting, stabilizing microtubules, or DNA methylation.