Question

In regulation by repression Multiple Choice an amino acid activates the repressor so that the repressor binds to the operator and prevents transcription. a sugar, such as lactose, acts as an inducer and combines with the repressor to prevent transcription. an inducer activates the activator so that it binds to DNA and prevents transcription. an amino acid binds to the operator, blocking the repressor, allowing transcription to proceed.

Answer 1

An amino acid activates the repressor so that the repressor binds to the operator and prevents transcription.

Step-by-step explanation:

In an operon, promoter is followed by operator which is finally followed by the structural genes to be transcribed. RNA Polymerase binds to the promoter and initiates transcription. A repressor can negatively control the transcription process by binding to the operator so that the RNA Polymerase is not able to move forward and transcription is halted.

For example: in trp operon, tryptophan amino acid binds to the repressor molecule which leads to change in repressor's shape. The repressor is now able to bind to the operator and prevent transcription.