Which of the following describes the Lac operon in E. coli when both lactose and glucose are present in the culture medium?
A. The Lac repressor, but not CAP, is bound to the Lac operon's regulatory DNA, and the Lac operon is not expressed.
B. Neither CAP nor the Lac repressor is bound to the Lac operon's regulatory DNA, and the Lac operon is not expressed.
C. CAP and the Lac repressor are both bound to the Lac operon's regulatory DNA, and the Lac operon is not expressed.
D. CAP binds to the Lac repressor, preventing it from binding to the Lac operon's regulatory DNA, and the Lac operon is expressed.
E. CAP, but not the Lac repressor, is bound to the Lac operon's regulatory DNA, and the Lac operon is expressed.
Ans: B. Neither CAP nor the Lac repressor is bound to the Lac operon's regulatory DNA, and the Lac operon is not expressed.
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