Assume that a mutation occurs in the promoter for the lacI regulatory gene and this mutation results in a tenfold increase in the transcription of lacI. What would be the expected consequences of such a mutation?
A) The lac structural genes will be fully expressed even in the presence of glucose and absence of lactose.
B) The lac operon would be expected to be regulated normally.
C) The lac structural genes will not be fully induced even in the absence of glucose and presence of lactose.
D) The lac structural genes will be partially expressed in the presence of glucose and fully expressed if lactose is also present.
E) The lac structural genes will now be fully expressed in the absence of glucose and lactose but not expressed in the absence of glucose and presence of lactose.

Question

Quizplus · Accepted Answer

A tenfold increase in lacI transcription would lead to more repressor proteins being produced, making it harder for lactose to induce the lac operon, thus preventing full induction even when lactose is present.

Assume That a Mutation Occurs in the Promoter for the LacI