Question

Which of the following is the best explanation in how the lac operon in E. coli bacteria functions in the absence of lactose?

The last option is RNA polymerase is blocked from conducting translation of the genes for processing lactose when it is absent

Answer 1

Step-by-step explanation:

The best explanation of how the lac operon in E. coli bacteria functions in the absence of lactose is that a repressor protein binds to the operator region of the operon, preventing RNA polymerase from transcribing the genes responsible for lactose metabolism. This is because the lac repressor protein is synthesized in an active form and is able to bind to the operator sequence of the operon, physically blocking the binding of RNA polymerase and preventing the transcription of the genes for lactose utilization.

In summary, the lac repressor protein prevents the transcription of the genes responsible for lactose metabolism in the absence of lactose by physically blocking the binding of RNA polymerase to the operon's promoter region.