Question

Which among the following are enzymes coded for by the lac operon?

• A. ꞵ - Galactosidase, Permease, Glycogen synthase
• B. ꞵ - Galactosidase, Permease, Transacetylase
• C. Permease, Glycogen synthase, Transacetylase
• D. ꞵ - Galactosidase, Permease, Phosphoglucose isomerase

Answer 1

The correct option is B ꞵ - Galactosidase, Permease, Transacetylase

Lac operon consists of structural genes which are a group of sequences that code for different proteins/ enzymes.

ꞵ - Galactosidase, permease and transacetylase are the various proteins /enzymes produced by the structural genes lac z, lac y and lac a respectively.

The functions of these enzymes are as follows:
ꞵ - Galactosidase → Digests lactose

Permease → Increase permeability of lactose

Transacetylase → plays an important role in lactose utilisation


Glycogen synthase catalyses glycogen synthesis in liver and skeletal muscle.

Phosphoglucose isomerase is an enzyme that catalyses isomerisation of glucose-6-phosphate to fructose-6-phosphate in TCA cycle.