When the substrate of a metabolic pathway is present in a bacterial cell,which of the following processes will occur?
A)transcription of the genes in a repressible operon
B)deactivation of the promoter for an operon
C)transcription of the genes in an inducible operon
D)allosteric regulation of an inducer

Question

Quizplus · Accepted Answer

When the substrate of a metabolic pathway is present, it can act as an inducer molecule to activate transcription of the genes in an inducible operon. This is because the substrate binds to a repressor protein, causing a conformational change that prevents it from binding to the operator region on the DNA. As a result, RNA polymerase can then access the promoter and initiate transcription of the operon. This allows the bacterium to produce the necessary enzymes to break down the substrate and generate energy. Option A is incorrect as a repressible operon would be turned off in the presence of excess substrate, while option B is incorrect as deactivation of the promoter would prevent transcription altogether. Option D is incorrect as allosteric regulation usually involves a molecule binding to an enzyme to modify its activity, rather than a gene or operon.

When the Substrate of a Metabolic Pathway Is Present in a Bacterial