Question

State whether the following statement is true or false.

In repressible operons, an inactive repressor is normally produced that is activated by the metabolic product (corepressor) of the reaction controlled by the operon enzymes.

Answer 1

This statement is true.

Explanation:

In a repressible operon, the regulatory gene produces a repressor protein in an inactive form (called an aporepressor) that cannot bind to the operator on its own. When the metabolic end product, or corepressor, becomes abundant, it binds to the inactive repressor and changes its shape to activate it. This activated complex then binds to the operator, blocking transcription and preventing the cell from wasting energy by synthesising a product that is already plentiful.