MCAT® ExamBiological and Biochemical Foundations of Living SystemsMedium
A research team is investigating a novel antiviral drug that targets viral replication by directly inhibiting the enzyme reverse transcriptase. This drug would be most effective against viruses that:
- AAre retroviruses and integrate their genetic material into the host genome.
- BUtilize DNA as their genetic material and replicate in the nucleus.
- CAre DNA viruses and assemble new viral particles in the cytoplasm.
- DAre RNA viruses and replicate directly in the host cell cytoplasm.
Show answer & explanationAnswer & explanation
Correct answer: A. Are retroviruses and integrate their genetic material into the host genome.
Reverse transcriptase is an enzyme unique to retroviruses (a type of RNA virus) that synthesizes DNA from an RNA template. Inhibiting this enzyme would specifically target retroviral replication, preventing them from converting their RNA genome into DNA for integration into the host genome.
Why the other options are wrong
- B. DNA viruses do not typically utilize reverse transcriptase; they replicate their DNA directly.
- C. DNA viruses do not use reverse transcriptase for replication or assembly.
- D. Many RNA viruses replicate directly from RNA to RNA without a DNA intermediate and thus do not use reverse transcriptase.
Reverse Transcriptase Function
Reverse transcriptase is an enzyme found in retroviruses that catalyzes the synthesis of DNA from an RNA template. This process, known as reverse transcription, allows the viral genetic information to be integrated into the host cell's genome.
- Synthesizes DNA from an RNA template.
- Characteristic enzyme of retroviruses (e.g., HIV).
- Essential for retroviral replication and integration into host genome.
- Target for many antiviral drugs.
Memory trick: Reverse Transcriptase: RNA's DNA Detour for Retroviruses.