The repressor is bound to the lac operon unless ____ is present.
A)lactose
B)lactase
C)transcription factor
D)RNA polymerase
E)promoter

Question

Quizplus · Accepted Answer

The lac operon is controlled by a repressor protein, which binds to the operator region and prevents transcription. However, when lactose is present, it binds to the repressor and changes its shape, causing it to release from the operator and allowing RNA polymerase to bind to the promoter and initiate transcription. As a result, transcription and translation of the genes coding for the lactose-metabolizing enzymes can occur. Therefore, choice A (lactose) is the best answer.

The Repressor Is Bound to the Lac Operon Unless ____