Question

When an end product of a metabolic pathway activates the repressor of the operon that produces enzymes for the pathway, it is called ______.

Answer 1

When an end product of a metabolic pathway activates the repressor of the operon that produces enzymes for the pathway, it is called a corepressor.

Explanation:

This process occurs in repressible operons, where the end product of a metabolic pathway acts as a corepressor. When the end product accumulates in excess, it binds to an inactive repressor protein, activating it. The activated repressor then binds to the operator, blocking RNA polymerase and stopping the production of more enzymes for that pathway. This ensures the cell does not waste energy synthesising substances it already has in abundance.