An operon is controlled by a repressor.When the repressor binds to a small molecule, it is released from binding to DNA near the operon.The operon is never expressed if a mutation prevents the repressor from binding to the small molecule.The type of control illustrated is:
A)negative inducible.
B)negative repressible.
C)positive inducible.
D)positive repressible.

Question

Quizplus · Accepted Answer

This scenario describes a negative inducible system. In such systems, the operon is normally off (negative control) but can be turned on (induced) when a small molecule binds to the repressor, causing it to release from the DNA, allowing transcription to proceed.

An Operon Is Controlled by a Repressor