Question

Imagine that you are studying a repressor protein. Your experiments show that the repressor binds to a promoter UNLESS maltose (a sugar) is present. Further, you show that the repressor binds directly to maltose and that maltose binding causes the repressor to leave the promoter. In this case, maltose is acting as:

An inducer.

An activator.

An operator.

A co-repressor

Answer 1

Ans:

An inducer

Explanation: An inducer is a small molecules that can binds with repressor protein and inhibits the repressor binding to the promoter. In the above experiment, maltose binds to repressor protein and leaves the promoter site for transcription. So, maltose is a inducer. An activator is a positive regulator protein that binds to the DNA binding site and increases the transcription. Operator is a site adjacent to the structural gene that determines whether the structural genes are to be repressed by repressor protein. An co- repressor is a molecule that binds to the repressor protein and stimulates its binding activity.