The structural gene that codes for transacetylase enzyme which can transfer acetyl group to `beta`-galactoside is

Options

A. lac z
B. lac a
C. i-gene
D. lac y

Answer

To answer the question regarding the structural gene that codes for the transacetylase enzyme, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Operon System**: The lac operon is a well-studied example of gene regulation in prokaryotes, particularly in E. coli. It consists of several components including structural genes, a promoter, an operator, and regulatory genes.

2. **Identify the Structural Genes**: The lac operon contains three structural genes:
- **lacZ**: Codes for β-galactosidase, which breaks down lactose into glucose and galactose.
- **lacY**: Codes for permease, which facilitates the transport of lactose into the cell.
- **lacA**: Codes for transacetylase, which transfers an acetyl group to β-galactosides.

3. **Focus on Transacetylase**: The question specifically asks for the gene that codes for the transacetylase enzyme. From the structural genes identified, we see that lacA is responsible for coding transacetylase.

4. **Conclusion**: Therefore, the structural gene that codes for the transacetylase enzyme which can transfer an acetyl group to β-galactoside is **lacA**.

### Final Answer:
The structural gene that codes for transacetylase enzyme is **lacA**.