Question

if many missense mutations change the nucleotide sequence of the promotor for lac ZYA. Please explain what would happen to the induction of the lac operon when glucose is absent and lactose is present.

Answer 1

When there is no glucose or low glucose levels,the Catabolite Activator Protein(CAP) is attached on by cAMP, which allows it to bind to the DNA, CAP allowa the RNA polymerase enzyme to bind to the DNA, which means the transcription process will be very high.

When the concentrations of gluose is high, no c AMP will be produces, which means the CAP will noot be able to bind to the DNA , which means the transcription will be at low rates.

Also, if Lactose is present , it binds to the lac operon repressor(which tends) to stop the procedure.Binding of the lactose to the lac repressor will cause the let go of the represssor , which means there will be binding of the promoter easily.