A mutation occurs in the operator region of the lac operon of E. coli, and the repressor protein is unable to bind. Which of the following would occur?
A) Synthesis of the repressor protein would stop.
B) Lactose would not enter the cell.
C) The promoter region would be transcribed.
D) The genes from the lac operon would not be transcribed.
E) Structural genes would be continuously transcribed.

Question

Quizplus · Accepted Answer

If the repressor protein cannot bind to the operator region of the lac operon, it cannot block RNA polymerase from transcribing the structural genes of the operon. Therefore, the genes responsible for lactose metabolism would be continuously transcribed, leading to the continuous production of the enzymes needed to metabolize lactose, regardless of the presence or absence of lactose.

A Mutation Occurs in the Operator Region of the Lac