Reverse transcriptase is a viral polymerase used by retroviruses. What product does it synthesize from an RNA template?

Introduction / Context:
Reverse transcriptase (RT) is central to the retroviral life cycle. It converts the single-stranded viral RNA genome into DNA that integrates into the host genome. Knowing the direction of information flow catalyzed by RT is a core concept.

Given Data / Assumptions:

• Template is RNA.
• Enzyme is reverse transcriptase.
• Product is a DNA copy to form a provirus.

Concept / Approach:
RT performs RNA-dependent DNA polymerization, creating DNA complementary to the RNA genome. It also has RNase H activity to degrade RNA in RNA–DNA hybrids and, subsequently, DNA-dependent DNA polymerase activity to synthesize the second DNA strand.

Step-by-Step Solution:

Verification / Alternative check:
Antiretroviral nucleoside analogs target RT's polymerase function, inhibiting synthesis of DNA from RNA.

Why Other Options Are Wrong:

• DNA from peptides: no enzyme translates peptides to nucleic acids.
• RNA from DNA: this is performed by RNA polymerase (transcription), not RT.
• RNA from RNA: RNA-dependent RNA polymerases, not classical retroviral RT.
• Protein directly from RNA: translation is done by ribosomes, not RT.

Common Pitfalls:
Assuming RT only makes the first strand; in fact, RT orchestrates both cDNA synthesis and second-strand synthesis via its polymerase and RNase H domains.

Final Answer:
DNA from RNA