Question

Which of the following environments would most likely lead to the transcription of the lactose operon?

a. The cyclic AMP levels are low.
b. There is glucose but no lactose in the cell.
c. There is more glucose in the cell than lactose.
d. The cyclic AMP and lactose levels are both high within the cell.
e. The cAMP level is high and the lactose level is low.

Answer 1

The transcription of the lactose operon is most likely when both cyclic AMP and lactose levels are high within the cell, due to the cAMP-CAP complex formation and the presence of lactose as an inducer. correct answer is not given in provided option D

Step-by-step explanation:

Among the options provided, the environment most likely to lead to the transcription of the lactose operon is when cyclic AMP (cAMP) and lactose levels are both high within the cell (option d). The lac operon is an inducible operon that requires two conditions for activation: a low or non-existent level of glucose, and the presence of lactose.

When glucose levels are low, cAMP levels rise and bind to the catabolite activator protein (CAP), forming a complex that promotes transcription of the lac operon. Simultaneously, lactose in the cell is converted to allolactose, which acts as an inducer by binding to the lac repressor, preventing it from binding to the operator, and allowing transcription to proceed.