In Tryptophan operon corepressor binds with

Options

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

Answer

**Step-by-Step Solution:**

1. **Understanding the Tryptophan Operon:**
- The tryptophan operon is a group of genes responsible for the synthesis of tryptophan in bacteria. It consists of structural genes that encode enzymes necessary for tryptophan production.

2. **Role of Co-repressor:**
- A co-repressor is a molecule that binds to a repressor protein and activates it. In the case of the tryptophan operon, tryptophan itself acts as a co-repressor.

3. **Binding of Co-repressor:**
- When tryptophan is abundant in the environment, it binds to the repressor protein. This binding activates the repressor.

4. **Location of Binding:**
- The activated repressor then binds to the operator region of the operon. The operator is a specific DNA sequence located downstream of the promoter and upstream of the structural genes.

5. **Inhibition of Gene Expression:**
- Once the repressor is bound to the operator, it prevents RNA polymerase from transcribing the structural genes, thereby inhibiting the synthesis of tryptophan.

6. **Conclusion:**
- Therefore, in the tryptophan operon, the co-repressor binds to the operator region, which is the correct answer.

**Final Answer:**
In the tryptophan operon, the co-repressor binds to the operator region.

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