Question

When an inducer is added to a medium containing an organism with a metabolic pathway controlled by a repressor, the inducer then Group of answer choices combines with the substrate and blocks induction. does not combine with, but rather functions as a chaperone molecule for, the enzyme-substrate complex. combines with the repressor and activates the repressor. combines with the substrate and activates induction. combines with the repressor and inactivates the repressor.

Answer 1

An inducer combines with a repressor and inactivates it, allowing RNA polymerase to transcribe the genes necessary for metabolizing the inducer substance, such as lactose in the lac operon.

Step-by-step explanation:

When an inducer is added to a medium containing an organism with a metabolic pathway controlled by a repressor, the correct action of the inducer is to combine with the repressor and inactivate it. For example, in the lac operon, the presence of lactose serves as an inducer. Lactose binds to the repressor protein, causing a conformational change which prevents the repressor from binding to the operator sequence. This action allows RNA polymerase to transcribe the genes necessary for the metabolism of lactose. The key aspect here is that the inducer directly interferes with the repressor's ability to block transcription, leading to the expression of the operon.

Answer 2

The correct answer is - combines with the repressor and inactivates the repressor.

Step-by-step explanation:

The role of inducers is to bind with a repressor in a metabolic pathway and cause them to change their shape. This modification of the shape in the repressor structure prevents them to bind with the DNA and the metabolic pathway continues.

So, inducers inactivate the repressors by binding them. For example in Lac operon lactose, an inducer bindswith the repressor and dissociates it from DNA and inactivates the repressor.