Enzyme needed for production of DNA from RNA template in certain viruses is

Options

A. RNA polymerase
B. Reverse transcriptase
C. DNA helicase
D. DNA polymerase.

Answer

To answer the question regarding the enzyme needed for the production of DNA from an RNA template in certain viruses, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Type of Virus**:
- Certain viruses, specifically retroviruses, have the ability to convert their RNA genome into DNA.

2. **Understand the Process**:
- The process of synthesizing DNA from an RNA template is known as reverse transcription. This is the reverse of the normal transcription process where DNA is used to synthesize RNA.

3. **Identify the Enzyme**:
- The enzyme responsible for catalyzing this reverse transcription is called reverse transcriptase. This enzyme is crucial for retroviruses to replicate their genetic material.

4. **Evaluate Other Options**:
- **RNA polymerase**: This enzyme synthesizes RNA from a DNA template, not the other way around.
- **DNA helicase**: This enzyme unwinds the DNA double helix, which is not relevant to the synthesis of DNA from RNA.
- **DNA polymerase**: This enzyme synthesizes DNA from a DNA template during DNA replication, not from RNA.

5. **Conclusion**:
- Based on the above analysis, the correct answer is reverse transcriptase, as it is specifically designed to synthesize DNA from an RNA template in retroviruses.

### Final Answer:
The enzyme needed for the production of DNA from an RNA template in certain viruses is **reverse transcriptase**.

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