Synthesis of a repressible enzyme is inhibited by
A)repressor alone bound to operator.
B)substrate bound to repressor.
C)substrate bound to promoter.
D)corepressor and repressor binding to operator.

Question

Quizplus · Accepted Answer

The question is describing a repressible system where the enzyme synthesis is usually active but can be turned off. The presence of a corepressor molecule can bind to the repressor protein and allow it to bind to the operator, inhibiting transcription of the enzyme. Therefore, only option D, where both corepressor and repressor are present to bind to the operator, can inhibit the synthesis of the enzyme in this repressible system. Options A, B, and C do not involve the necessary components to inhibit enzyme synthesis in a repressible system.

Synthesis of a Repressible Enzyme Is Inhibited by