In lac operon RNA polymerase binds with

Options

A. Promoter gene
B. Operator gene
C. Structural gene
D. Regulator gene

Answer

To solve the question regarding where RNA polymerase binds in the lac operon, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Lac Operon Structure**: The lac operon consists of several key components: the promoter, operator, and structural genes (lacZ, lacY, and lacA). Each of these plays a specific role in gene expression.

2. **Identifying the Role of the Promoter**: The promoter is a specific DNA sequence where RNA polymerase binds to initiate transcription. It acts as a recognition site for RNA polymerase and is crucial for the transcription process.

3. **Examining Other Options**:
- **Operator Gene**: The operator is a regulatory sequence that can bind repressor proteins, but it is not where RNA polymerase binds.
- **Structural Genes**: These genes are transcribed after RNA polymerase binds to the promoter, but they are not the binding site for RNA polymerase itself.
- **Regulator Gene**: This gene produces a repressor protein that can inhibit transcription but does not serve as a binding site for RNA polymerase.

4. **Conclusion**: Since RNA polymerase binds to the promoter to initiate transcription of the structural genes, the correct answer is that RNA polymerase binds with the **promoter gene**.

### Final Answer:
RNA polymerase binds with the **promoter gene**.

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