In lac operon, which of the following codes for the enzyme β-galactosidase?

Correct option is A

What is the Lac Operon?
The lac operon is a classic example of gene regulation in prokaryotes (especially E. coli).
It enables bacteria to use lactose as an energy source by producing necessary enzymes only when lactose is present and glucose is absent.
�� Key Components of Lac Operon:
Structural Genes:
Lac Z – ✅ Encodes β-galactosidase, which breaks down lactose into glucose and galactose.
Lac Y – Encodes lactose permease, helps transport lactose into the cell.
Lac A – Encodes transacetylase, whose role is less directly involved in lactose metabolism.
Regulatory Elements:
Promoter (P) – Site where RNA polymerase binds.
Operator (O) – Binding site for the repressor protein. It does not code for any enzyme.
�� Explanation of Options:
(a) Lac Z – ✅ Correct, codes for β-galactosidase, the key enzyme for lactose breakdown.
(b) Lac Y – ❌ Codes for lactose permease, not β-galactosidase.
(c) Lac A – ❌ Codes for transacetylase, not involved in lactose cleavage.
(d) Operator – ❌ A regulatory DNA sequence, not a gene; does not produce an enzyme.