The lac operon of E.coli consists of
A) a promoter and an operator.
B) an operator and three structural genes.
C) three structural genes and a promoter.
D) a promoter,an operator,and three structural genes.
E) a promoter,a director,and two structural genes.

Question

Quizplus · Accepted Answer

The lac operon of E.coli consists of a promoter (to which RNA polymerase binds), an operator (a regulatory element that controls the expression of the operon), and three structural genes (lacZ, lacY, and lacA) that code for enzymes involved in lactose metabolism. Therefore, choice D, which includes all three elements, is the correct answer.

The Lac Operon of E.coli Consists of