Question

How are the structural genes inactivated in lac operon in E.coli? Explain.

Answer 1

The lac operon in E.coli has a promoter site (p), regulatory site (i) and operator site (o). It also has three structural gene namely z, y and a. The regulatory gene codes for a repressor protein and repressor protein has high affinity for the operator region and prevents RNA polymerase from transcribing the structural gene. Thus, the lac operon gene is inactivated.