The lac operon
A) is an example of positive control.
B) produces lactose.
C) is an example of a regulon.
D) is an example of negative control.
E) is an example of constitutive control.

Question

Quizplus · Accepted Answer

The lac operon is negatively controlled, which means that the repressor protein binds to the operator region of the DNA and prevents transcription of the genes. This repression can be relieved by the presence of lactose, which binds to the repressor and prevents it from binding to the DNA.

Answer: C
 The lac operon is part of a larger regulon, which includes other genes involved in lactose metabolism. The regulon is controlled by multiple signals, including glucose levels and cAMP levels, and the expression of the different genes can be coordinated to optimize energy use by the cell.

The Lac Operon