There is a mutation in the operator of the trp operon in a cell such that the trp repressor is unable to bind to the operator. If tryptophan is added to the cell, what will happen?
A) Tryptophan will bind to the repressor, and trp enzymes will be produced.
B) Tryptophan will bind to the repressor, and trp enzymes will not be produced.
C) Tryptophan will not bind to the repressor, and trp enzymes will be produced.
D) Tryptophan will bind to the operator, and trp enzymes will be produced.

Question

Quizplus · Accepted Answer

CIn this scenario, since the trp repressor cannot bind to the mutated operator, the regulation of the trp operon by the repressor is disrupted. Normally, tryptophan binds to the trp repressor, causing it to change shape and bind to the operator, thereby blocking transcription. However, with the mutation preventing repressor binding, transcription of the trp operon will proceed regardless of whether tryptophan is present or not. Thus, trp enzymes will be produced whether tryptophan binds to the repressor (A) or not (C), making both A and C correct under the given conditions.

There Is a Mutation in the Operator of the Trp