Question

How is the cell in Diagram B effectively using its resources?

A) the cell continually produces the enzymes needed to break down lactose.

B) since lactose is absent, the repressor protein is blocking the genes and stopping transcription.

C) RNA polymerase is transcribing the genes since lactose is present.

D) since lactose is present, the repressor protein will begin transcription

Answer 1

B

Step-by-step explanation:

The lactose molecules are allosteric to the repressor. When they bind their site on the repressor, the protein changes shape and is unable to bind the regulatory site on the DNA. This allows the polymerase enzyme to bind the promoter region and begins transcription of the gene. When the lactose is absent the repressor is able to bind to the region blocking out the polymerase.