Which of the Following Occurs When the Lactose Enters the Cell

Question

Which of the following occurs when the lactose enters the cell?
A)The repressor protein attaches to the regulator.
B)Allolactose binds to the repressor protein.
C)Allolactose binds to the regulator gene.
D)The repressor protein and allolactose bind to RNA polymerase.
E)RNA polymerase attaches to the regulator.

Accepted Answer

When lactose enters the cell, it is converted to allolactose which binds to the repressor protein. This binding changes the shape of the repressor protein, causing it to fall off the operator region of the DNA. This allows RNA polymerase to bind to the promoter region and transcribe the genes necessary for lactose metabolism.