You are studying the regulation of a prokaryotic operon.Experimental results suggest that the operon is governed by negative control.Based on this information,you conclude that
A)the operon is ON in the absence of its regulatory protein.
B)the operon is OFF in the absence of its regulatory protein.
C)the presence of an inducer will always cause a repressor to bind the operator.
D)the presence of an inducer will always prevent a repressor from binding the operator.

Question

Quizplus · Accepted Answer

Negative control means that the operon is normally off and is turned on only in the absence of a regulatory protein (usually a repressor). Therefore, the operon is not active in the absence of the regulatory protein, leading to the conclusion that the operon is OFF in the absence of its regulatory protein. Choices C and D are incorrect because the effect of an inducer on the regulatory protein depends on the specific mechanism of regulation and cannot be generalized.

You Are Studying the Regulation of a Prokaryotic Operon