Which of the following genotypes produces functional lactose permease constitutively?

Question

Quizplus · Accepted Answer

The lactose permease gene is a part of the lac operon which is regulated by the lac repressor protein. In the absence of lactose, the repressor protein binds to the operator region and inhibits transcription of the lactose permease gene. When lactose is present, it binds to the repressor, causing a conformational change and preventing it from binding to the operator, allowing transcription of the lactose permease gene. Therefore, a genotype that produces functional lactose permease constitutively must have a mutation in the operator region or the repressor protein that prevents it from binding to the operator. Option C has a mutation in the promoter region () and the wild-type gene for the repressor (I^{), which would allow for constitutive transcription of the lactose permease gene.}

Which of the Following Genotypes Produces Functional Lactose Permease Constitutively