Name the enzyme that facilitates opening of DNA helix during transcription.

Options

A. DNA helicase
B. DNA polymerase
C. RNA polymerase
D. DNA ligase

Answer

To answer the question "Name the enzyme that facilitates opening of DNA helix during transcription," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Transcription**:
- Transcription is the process where RNA is synthesized from a DNA template. This primarily involves the formation of messenger RNA (mRNA).

2. **Role of Enzymes in Transcription**:
- During transcription, specific enzymes are involved in the process of unwinding the DNA double helix to allow access to the DNA strands.

3. **Identifying the Enzymes**:
- The options given are:
- DNA helicase
- DNA polymerase
- RNA polymerase
- DNA ligase

4. **Analyzing Each Option**:
- **DNA helicase**: This enzyme unwinds the DNA helix, but it is primarily involved in DNA replication, not transcription.
- **DNA polymerase**: This enzyme is responsible for synthesizing new DNA strands during replication. It does not play a role in transcription.
- **RNA polymerase**: This enzyme is crucial for transcription. It binds to the DNA and facilitates the opening of the DNA helix to allow the synthesis of RNA.
- **DNA ligase**: This enzyme is involved in joining DNA fragments together, mainly during replication and repair processes.

5. **Conclusion**:
- The enzyme that facilitates the opening of the DNA helix during transcription is **RNA polymerase**.

### Final Answer:
**RNA polymerase**