Question

In lac operon, the genes a, i, y and z code respectively for

• A. respressor protein, permease, $\beta$-galactosidase, transacetylase
• B. transacetylase, permease, $\beta$-galactosidase, repressor protein
• C. permease, transacetylase, repressor protein, $\beta$-galactosidase
• D. transacetylase, repressor protein, permease, $\beta$-galactosidase

Answer 1

The correct option is D transacetylase, repressor protein, permease, $\beta$-galactosidase

The lac operon consists of one regulatory gene (the I gene) and three structural genes (Z, Y, and A). The I gene codes for the repressor of the lac operon. The Z gene codes for $\beta$-galactosidase, which is primarily responsible for the hydrolysis of the disaccharide lactose into its monomeric units, galactose and glucose. The Y gene codes for permease, which increases permeability of the cell to $\beta$-galactosides. The A gene encodes a transacetylase.