Question

In lac operon, $i$-gene codes for

• A. inducer of lac operon
• B. represser of lac operon
• C. hydrolysis of disaccharide
• D. permease

Answer 1

Answer: (B)

represser of lac operon

Answer 2

The lac operon consists of one regulatory gene (the $i$-gene) and three structural genes ($z, y$ and $a$). The $z$-gene codes for the represser of the lac operon. The $\%$-gene codes for $P$-galactosidase ($\beta$ -gal), 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.