Question

How does active CAP induce expression of the genes of the lactose operon?

Answer 1

By opening up the Double Helix...

Explanation:

CAP: Catabolite Activator Protein....

Activated by cAMP ( cyclic AMP, Adenosine Mono Phosphate) it binds to the promotor region and opens up the Double Helix. It basically deforms the helix (it bends it).

This enables RNA Polymerase to begin transcription. (for the genes involved in Lactose catabolism).

Nice Picture:

Pink = DNA of course, Blue = CAP....