Repressor of operon model binds itself to

Options

A. regulator gene
B. promoter gene
C. structural gene
D. operator gene

Answer

**Step-by-Step Solution:**

1. **Understanding the Operon Model**: The operon model consists of a cluster of genes that are regulated together. It typically includes three main components: the promoter, the operator, and the structural genes.

2. **Identifying the Components**:
- **Promoter Gene**: This is the site where RNA polymerase binds to initiate transcription.
- **Operator Gene**: This is the regulatory sequence that the repressor binds to, controlling access to the promoter.
- **Structural Genes**: These genes code for proteins that are involved in a specific metabolic pathway.

3. **Role of the Regulatory Gene**: The regulatory gene (often denoted as 'I') produces a repressor protein. This repressor is crucial for regulating gene expression in the operon.

4. **Binding of the Repressor**: The repressor protein produced by the regulatory gene binds specifically to the operator gene. This binding prevents RNA polymerase from attaching to the promoter.

5. **Effect of Repressor Binding**: When the repressor is bound to the operator, it blocks RNA polymerase from moving along the DNA to transcribe the structural genes. This effectively turns off the operon, preventing the synthesis of proteins coded by the structural genes.

6. **Conclusion**: Therefore, the repressor of the operon model binds itself to the operator gene.

**Final Answer**: The repressor of the operon model binds itself to the **operator gene**.

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