Question

What two events are are required for maximal lac operon expression?.

Answer 1

For maximal lac operon expression, two events are required: glucose levels must be low or absent, and lactose must be present. This allows for the optimal transcription of the lac operon. The CAP protein and allolactose play key roles in regulating the expression of the lac operon.

Step-by-step explanation:

For maximal lac operon expression, two events are required. First, glucose must be absent or at very low levels. Second, lactose must be present. These conditions allow for the lac operon to be transcribed maximally. When glucose is absent, the CAP protein binds to the operator region, enhancing transcription. When lactose is present, allolactose binds to the lac repressor, preventing it from blocking transcription. These two events together enable maximal lac operon expression.

Answer 2

These two events in combination – the binding of the activator and the release of the repressor – allow RNA polymerase to bind strongly to the promoter and give it a clear path for transcription. They lead to strong transcription of the lac operon and production of enzymes needed for lactose utilization.