Question

What is the role of y gene in lac operon?

• A. Codes for β-galactosidase
• B. Codes for permease
• C. Codes for repressor gene
• D. Codes for transacetylase

Hint:

lac Z → β-galactosidase, lac Y → Permease, lac A → Transacetylase.

Answer 1

The Correct Option is B

Step 1: Genes in lac operon.
The lac operon in E. coli has three structural genes:
- lac Z → β-galactosidase
- lac Y → Permease
- lac A → Transacetylase
Step 2: Function of lac Y.
The lac Y gene codes for permease, which facilitates lactose entry into the bacterial cell.
Step 3: Conclusion.
Thus, the y gene in lac operon codes for permease.