Main enzyme of DNA replication is -

Options

A. DNA dependent RNA polymerase
B. DNA dependent DNA polymerase
C. RNA dependent RNA polymerase
D. RNA dependent DNA polymerase

Answer

To answer the question regarding the main enzyme of DNA replication, we can follow these steps:

### Step-by-Step Solution:

1. **Understand DNA Replication**:
- DNA replication is the process by which a cell makes an identical copy of its DNA. This involves synthesizing new strands of DNA from the original parent strands.

2. **Identify the Options**:
- The options provided are:
- A) DNA dependent RNA polymerase
- B) DNA dependent DNA polymerase
- C) RNA dependent RNA polymerase
- D) RNA dependent DNA polymerase

3. **Analyze Each Option**:
- **Option A: DNA dependent RNA polymerase**:
- This enzyme synthesizes RNA using DNA as a template. It is involved in transcription, not DNA replication. Therefore, this option is incorrect.

- **Option B: DNA dependent DNA polymerase**:
- This enzyme synthesizes new DNA strands using existing DNA as a template. It is the key enzyme involved in DNA replication. This option is correct.

- **Option C: RNA dependent RNA polymerase**:
- This enzyme synthesizes RNA from an RNA template. It is involved in RNA replication, not DNA replication. Thus, this option is incorrect.

- **Option D: RNA dependent DNA polymerase**:
- This enzyme synthesizes DNA from an RNA template, a process known as reverse transcription. It is not the main enzyme for DNA replication, making this option incorrect.

4. **Conclusion**:
- After analyzing all the options, the main enzyme of DNA replication is **DNA dependent DNA polymerase** (Option B).

### Final Answer:
The main enzyme of DNA replication is **DNA dependent DNA polymerase**.

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