You identify a mutation affecting the lac operon and find the following: lacZ is expressed whether lactose is present or not.
LacI is expressed normally.
What could be WRONG in this mutant?

Question

Quizplus · Accepted Answer

The lacO region is where the lac repressor protein binds to prevent transcription of the lacZ gene in the absence of lactose. If lacO is deleted, then the repressor cannot bind and transcription of lacZ will occur regardless of lactose presence. The other options (A, C, D) would not lead to the observed phenotype.

You Identify a Mutation Affecting the Lac Operon and Find