NEETZoologyMolecular Basis of Inheritance
How is the expression of the lac operon regulated?
Options
- ABy the i gene
- BBy the z gene
- CBy the y gene
- DBy the a gene
Correct answer
A. By the i gene
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