What is the Function of Allolactose in Regulation of the Lac

Question

What is the function of allolactose in regulation of the lac operon?
A)Inducer
B)Repressor
C)Activator
D)Promoter
E)Regulatory protein

Accepted Answer

Allolactose is an inducer and binds to the repressor protein of the lac operon, causing it to undergo a conformational change and be unable to bind to the operator region of the DNA. This allows RNA polymerase to bind to the promoter and transcribe the genes needed to utilize lactose as a source of energy.