Which one of the following enzyme brings about hydrolysis of lactose to glucose and galactose?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → β-galactosidase
Option (4) β-galactosidase — Correct. Coded by the z gene, it hydrolyses lactose into galactose and glucose.
NCERT Extract:
The Lac Operon – “… 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 a gene encodes a transacetylase.”