what arw the advantage and disadvantage of negative vs positive controll of lac operon?
Answers
Answer:
The lac repressor binds to the operator region and negatively controls (prevents) transcription. However, when CAP (catabolite gene activating protein) binds upstream of this operator region near the promoter and transcription increases, this is an example of a positive control system.
Answer:
Whereas the difference between a negatively regulated vs a positively regulated system is about the behavior of the regulatory protein. The problem with a negatively regulated system is that for controlling a multi copy plasmid you need to have excess repressor present, and usually a single copy of the repressor gene on the chromosome does not suffice. So often negatively regulated promoters are not as tightly regulated and may have substantial basal expression. Whereas for positive regulation you don't have the same difficulty and the basal uninduced expression levels are usually lower