There are two basic types of transcriptional control: negative and positive. In negative control, when a regulatory protein (repressor) binds to DNA, transcription is inhibited; in positive control, when a regulatory protein (activator) binds to DNA, transcription is stimulated. Some operons are inducible; transcription is normally off and must be turned on. Other operons are repressible; transcription is normally on and must be turned off.
-In a negative repressible operon, the regulator protein is synthesized as
A) an active activator.
B) an inactive activator.
C) an active repressor.
D) an inactive repressor

Question

Quizplus · Accepted Answer

In a negative repressible operon, the regulator protein is synthesized as an inactive repressor. It becomes active only when it binds to a corepressor, allowing it to bind to the operator and inhibit transcription.

There Are Two Basic Types of Transcriptional Control: Negative and Positive