Question

In lac operon model, as proposed by Jacob and Monod, how many structural genes are controlled by a single operator gene?

• A. 1
• B. 2
• C. 3
• D. None of the above

Answer 1

Answer: (C)

3

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