In a repressible operon,the repressor molecule
A) can control the operon only after it is activated by a corepressor.
B) can repress the transcription of the operon on its own.
C) is a molecule made from the operon.
D) binds to the mRNA.
E) must first be made negative to control the operon.

Question

Quizplus · Accepted Answer

In a repressible operon, the repressor molecule can control the operon only after it is activated by a corepressor. The corepressor binds to the repressor, changing its conformation so that it can bind to the operator region and block transcription. Without the corepressor, the repressor cannot bind and the operon continues to be transcribed.

In a Repressible Operon,the Repressor Molecule