In the lac operon, CAP binding to the CAP site of the promoter ____.
A) occurs when glucose is present
B) inhibits RNA polymerase from binding to the promoter
C) occurs when cAMP is absent
D) helps the repressor protein bind to the operator
E) enables RNA polymerase to transcribe the operon's genes

Question

Quizplus · Accepted Answer

CAP (catabolite activator protein) binding to the CAP site enhances the binding of RNA polymerase to the promoter, facilitating transcription of the operon's genes. This occurs in low glucose conditions, when cAMP levels are high, leading to the formation of a CAP-cAMP complex that binds to the DNA.

In the Lac Operon, CAP Binding to the CAP Site