Question

At the promoter for the lac operon, how does the dna loop block transcription?

Answer 1

The DNA loop blocks transcription by preventing RNA polymerase from binding to the promoter region of the lac operon. This is because the DNA loop physically separates the promoter from the RNA polymerase, preventing the polymerase from accessing the promoter and initiating transcription.

Answer 2

by creating torsional strain in the DNA at the promoter which prevents the transition from closed to open promoter complex.