A virus with RNA-dependent RNA polymerase
a. synthesizes DNA from an RNA template.
b. synthesizes double-stranded RNA from an RNA template.
c. synthesizes double-stranded RNA from a DNA template.
d. transcribes mRNA from DNA.
e. none of the above

Verified step by step guidance

1. Understand the role of RNA-dependent RNA polymerase: This enzyme is crucial for viruses that have RNA genomes. It catalyzes the replication of RNA from an RNA template.
2. Identify the correct function: RNA-dependent RNA polymerase synthesizes RNA from an RNA template, not DNA. This is a key feature of RNA viruses, particularly those with single-stranded RNA genomes.
3. Evaluate the options: Option (a) involves synthesizing DNA, which is not the function of RNA-dependent RNA polymerase. Option (c) involves a DNA template, which is also incorrect. Option (d) involves transcribing mRNA from DNA, which is a function of DNA-dependent RNA polymerase, not RNA-dependent RNA polymerase.
4. Focus on option (b): This option suggests synthesizing double-stranded RNA from an RNA template, which aligns with the function of RNA-dependent RNA polymerase in some RNA viruses.
5. Conclude with the correct choice: Based on the understanding of RNA-dependent RNA polymerase, the correct answer is the one that describes the synthesis of RNA from an RNA template.

Key Concepts

RNA-dependent RNA polymerase

RNA-dependent RNA polymerase (RdRp) is an enzyme that synthesizes RNA from an RNA template. This enzyme is crucial for the replication of RNA viruses, allowing them to produce their RNA genomes and mRNA for protein synthesis. Unlike DNA-dependent RNA polymerase, which uses DNA as a template, RdRp specifically catalyzes the formation of RNA strands, making it essential for the life cycle of RNA viruses.

RNA virus replication

RNA viruses replicate their genetic material using RNA-dependent RNA polymerase. During this process, the viral RNA serves as a template to produce complementary RNA strands, which can be either mRNA for protein synthesis or new viral genomes. Understanding this replication mechanism is key to answering questions about the behavior and characteristics of RNA viruses.

Transcription vs. Replication

Transcription is the process of synthesizing RNA from a DNA template, while replication refers to the duplication of genetic material. In the context of RNA viruses, RdRp is involved in replication rather than transcription, as it synthesizes RNA from an RNA template. This distinction is important for understanding the functions of different polymerases and the life cycles of various viruses.