A gene is inducible and under negative control. Which of the following pairs will allow expression of this gene?
A) Activator + repressor
B) Activator + inhibitor
C) Repressor + inducer
D) Repressor + co-repressor

Question

Quizplus · Accepted Answer

If a gene is inducible, that means its expression can be turned on in the presence of an inducer. However, if it is under negative control, that means a repressor must be present to prevent its expression. Therefore, the only pair that would allow expression of this gene is a repressor and an inducer. The repressor would be bound to the operator region of the gene, preventing transcription. When an inducer is present, it binds to the repressor and inactivates it, allowing transcription of the gene to occur.

A Gene Is Inducible and Under Negative Control