In a Negative,repressible Regulatory Mechanism,transcription of the Structural Gene(s)occurs In

Question

In a negative,repressible regulatory mechanism,transcription of the structural gene(s)occurs in
A) the absence of the co-repressor, but not in its presence.
B) the absence of the inducer but not in its presence.
C) the absence or presence of the co-repressor.
D) the presence of the co-repressor, but not in its absence.
E) None of these are correct.

Accepted Answer

In a negative, repressible regulatory mechanism, transcription is normally on but can be turned off when a co-repressor binds to the repressor, making it active. Therefore, transcription occurs in the absence of the co-repressor because the repressor is inactive without it, allowing gene expression.