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Molecular Basis of Inheritance

Match List I with List II.
List – I List – II
A. Gene ‘a’ - I. β – galactosidase
B. Gene ‘y’ - II. Transacetylase
C. Gene ‘i’ - III. Permease
D. Gene ‘z’ - IV. Repressor protein
Choose the correct answer from the options given below:

Molecular Basis of Inheritance


The lac operon consists of one regulatory 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 (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.

Hence, all the three gene products in lac operon are required for metabolism of lactose

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