A mutation in the i gene encoding the lac operon repressor protein causes this protein to lose its ability to bind to the operator site. Which would you expect to observe in an E. coli population having this mutation?

Question

Quizplus · Accepted Answer

The lac operon is only expressed when lactose is present and glucose is absent. However, in a population of E. coli with a mutation in the i gene causing the lac repressor protein to lose its ability to bind to the operator site, the lac operon would be constitutively expressed, meaning the cells would express lac genes even in the absence of lactose. Therefore, the best choice is D. The cells would express lac genes when lactose is absent.

A Mutation in the I Gene Encoding the Lac Operon