In the presence of both lactose and glucose, which of the following occurs with the E. coli lac operon?
A) The lacI gene does not produce repressor.
B) The cAMP-CAP complex is not available to bind near or at the lac promoter.
C) The lacZ and lacY genes are fully expressed.
D) Lactose is converted to glucose and galactose.
E) Lactose binds to the operator.

Question

Quizplus · Accepted Answer

In the presence of glucose, the cAMP levels are low, preventing the formation of the cAMP-CAP complex, which is necessary for the activation of the lac operon. Thus, the lac operon is not fully activated even if lactose is present.

In the Presence of Both Lactose and Glucose, Which of the Following