Actual site of transcription intiation in Lac operon is

Options

A. Promoter region
B. Operator
C. Inhibitor
D. Structural genes

Answer

### Step-by-Step Solution

1. **Understand the Lac Operon**: The Lac operon is a set of genes responsible for the metabolism of lactose in bacteria, particularly E. coli. It consists of structural genes, a promoter, an operator, and regulatory genes.

2. **Identify the Components**: The main components of the Lac operon include:
- **Promoter Region**: The site where RNA polymerase binds to initiate transcription.
- **Operator**: A regulatory sequence that can block transcription when a repressor protein binds to it.
- **Structural Genes**: Genes that code for proteins involved in lactose metabolism.
- **Regulatory Genes**: Genes that produce repressor proteins.

3. **Determine the Site of Transcription Initiation**: The transcription initiation site is where RNA polymerase binds to the DNA to start synthesizing RNA from the DNA template.

4. **Evaluate the Options**:
- **Promoter Region**: This is the correct answer as it is the binding site for RNA polymerase.
- **Operator**: This is a regulatory site and does not initiate transcription.
- **Inhibitor**: This term does not refer to a specific site in the Lac operon.
- **Structural Gene**: These genes are transcribed but are not the site of transcription initiation.

5. **Conclusion**: The actual site of transcription initiation in the Lac operon is the **Promoter Region**.

### Final Answer
The actual site of transcription initiation in the Lac operon is the **Promoter Region**.

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