Which gene in the lac operon is responsible for the hydrolysis of lactose into its monomeric units?

Step-by-step solution

The lac operon consists of one regulatory gene (the i gene – here the term i does not refer to inducer, rather it is derived from the word inhibitor) 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 (β-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 β-galactosides. The g