How would a cap− mutation that produces an inactive cap protein affect transcriptional control of the lac operon? how would a mutation that produces an inactive cap protein affect transcriptional control of the operon? lac operon transcription in the presence of lactose would be enhanced. lac operon transcription would not be repressible. lac operon transcription would be constitutive. lac operon transcription would be reduced.

The answer is: The lac operon transcription would be reduced.

Explanation:

The lac operon is the machinery that bacteria uses to break down lactose to use it as an energy source when there is no glucose around. The catabolite activator protein (CAP) senses glucose via a molecule called cAMP. If the levels of glucose are high then no cAMP is produced and therefore no cAMP would be able to bind CAP. That would leave CAP inactive and the transcription would occur but at low levels. The same would happen if CAP protein would have a mutation that would leave it inactive.