Which one of the following synthesize a repressor protein :-

Options

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

Answer

To determine which of the following options synthesizes a repressor protein, let's analyze each option step by step:

### Step 1: Understand the Role of Each Gene Type
1. **Regulator Gene**: This gene is responsible for producing regulatory proteins, including repressor proteins. These proteins can bind to operator regions and inhibit the transcription of certain genes.

2. **Promoter Gene**: The promoter is a sequence of DNA that initiates transcription of a particular gene. It does not synthesize proteins itself; instead, it serves as a binding site for RNA polymerase.

3. **Structural Gene**: This type of gene codes for proteins or RNA molecules that have a specific function in the cell. It does not code for regulatory proteins such as repressors.

4. **Operator Gene**: The operator is a segment of DNA that a repressor protein can bind to. It does not synthesize proteins; rather, it regulates the expression of adjacent genes.

### Step 2: Identify the Correct Answer
From the analysis:
- The **regulator gene** is the only option that synthesizes repressor proteins.
- The other options (promoter gene, structural gene, and operator gene) do not synthesize repressor proteins.

### Conclusion
The correct answer is **Regulator Gene**.

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