Synthesis of an inducible enzyme requires Select one:

a. corepressor and repressor binding to operator.

b. substrate bound to repressor.

c. repressor alone bound to operator.

d. substrate bound to promoter.

Answer: B

Explanation:

Synthesis of an inducible enzyme requires the substrate bound to repressor.

In the synthesis of a specific inducible enzymes, a substrate on which the enzyme acts must bind to the repressor that prevents the synthesis of the inducible enzyme. Example of an inducible enzyme is β-galactosidase in Escherichia coli that degrades lactose and galactose.

The synthesis of β-galactosidase is regulated by a repressor protein, that binds to the region of deoxyribonucleic acid (DNA) that codes for the synthesis of β-galactosidase. If lactose or galactose (substrate) is present, it acts as an inducer which induce the repressor protein from binding to DNA. Hence the enzyme is synthesized