How is lac operon transcription regulated by the prescence or abscence of lactos
ID: 79963 • Letter: H
Question
How is lac operon transcription regulated by the prescence or abscence of lactose? A) When lactose is NOT available, the repressor will bind to the promoter and block RNA polymerase from transcribing the genes of the lac operon. B) When lactose is available, the repressor will bind to the lactose instead of blocking RNA polymerase C) When Lactose is NOT available , the repressor will bind to allolactose. D) When lactose is available , allolactose is produced and binds to the operator, blocking RNA polymerase. E) In the abscence of lactose, transcription occurs at a low level resulting in the production of allolactose which in turn stimulates the cell to take up lactose.
Explanation / Answer
Answer B - When lactose present repressor molecules binds to lactose or allolactose.
A-Lactose is not present repressor molecules binds to operator region not the Polymerase region.
C - Lactose is not present repressor molecules binds to operator.
D - When lactose present allolactose binds to repressor not to operator.