Final answer:
A mutation in the lac operon's operator sequence that prevents repressor binding would lead to constitutive expression of the operon's genes for lactose metabolism.
Step-by-step explanation:
If the operator sequence of the lac operon contained a mutation that prevented the repressor protein from binding the operator, the operon would be constitutively expressed. This means that the genes of the lac operon, which are responsible for the metabolism of lactose, would be continuously transcribed and translated into proteins, even in the absence of lactose. Normally, when lactose is not present, the repressor protein binds to the operator to block transcription.
However, with the inability of the repressor to bind, RNA polymerase would have unrestricted access to the promoter and would constantly transcribe the operon's genes.If the operator sequence of the lac operon contained a mutation that prevented the repressor protein from binding the operator, the operon would be constitutively expressed. This means that the lac operon would be constantly on and the genes involved in lactose metabolism (lacZ, lacY, and lacA) would continuously produce their corresponding proteins.