Most $\mathrm{RNA}$ viruses carry which of the following enzymes to replicate their genome?

• A. Reverse transcriptase
• B. $\mathrm{DNA}$ polymerase
• C. Helicase
• D. $\mathrm{RNA}$-dependent $\mathrm{RNA}$ polymerase

Answer: (D)

Verified step by step guidance

1. Understand the nature of RNA viruses: RNA viruses have RNA as their genetic material, and they need to replicate this RNA to produce new viral particles.
2. Identify the enzyme required for RNA replication: RNA viruses typically use an enzyme that can synthesize RNA from an RNA template, which is different from the enzymes used in DNA replication.
3. Differentiate between the enzymes: Reverse transcriptase is used by retroviruses to convert RNA into DNA, DNA polymerase is used to synthesize DNA from a DNA template, and helicase unwinds DNA strands.
4. Recognize the specific enzyme for RNA viruses: RNA-dependent RNA polymerase is the enzyme that catalyzes the replication of RNA from an RNA template, which is essential for the replication of RNA viruses.
5. Conclude that RNA-dependent RNA polymerase is the enzyme carried by most RNA viruses to replicate their genome, as it directly synthesizes RNA from an RNA template.