Question

In lac operon, structural gene 'Z' synthesizes

• A. $\beta$ - galactosidase
• B. Galactosidase permease
• C. Galactosidase transacetylase
• D. None of the above

Answer 1

Answer: (A)

$\beta$ - galactosidase

The lac operon is an operon responsible for transport and metabolism of lactose in Escherichia coli and other bacteria and carries the genes that codes for enzymes involved in lactose metabolism only. The lac operon has three structural genes. The lac Z gene codes for $\beta$-galactosidase which converts lactose into glucose and galactose. The lac Y gene codes for $\beta$-galactoside permease which transports lactose into the cell. The lac A gene codes for $\beta$-galactoside transacetylase. Thus, the correct answer is option A.