Question

What would be the result of a mutation that deactivates the regulatory gene of a repressible operon in an escherichia coli cell?

Answer 1

The correct answer is: B) continuous transcription of the structural gene controlled by that regulator

A regulatory gene is gene that encodes for a protein, such as a repressor (or activators) that controls the transcription of another gene or group of genes.

The regulatory gene of a repressible operon encodes for the repressor that inhibits gene transcription. So, when that repressor isn’t active, transcription occurs continuously.