An extremely large lactose source is encountered by an E. coli cell in the lumen of the small intestine of a human who just ate an entire carton of ice cream. Which of the following would most likely be a contributor to why the E. coli does not metabolize any of the lactose?
A) presence of allolactose
B) presence of phosphorylated adenylate cyclase
C) absence of glucose
D) absence of cAMP

Question

Quizplus · Accepted Answer

The absence of cAMP would prevent the activation of CAP (catabolite activator protein), which is necessary for the transcription of the lac operon, thus inhibiting lactose metabolism.

An Extremely Large Lactose Source Is Encountered by an E