Q. 74.5( 6 Votes )
Why does the lac
The enzyme beta-galactosidase is synthesized by E.coli, is used to catalyze the hydrolysis of a disaccharide, lactose into galactose and glucose.
Lactose binds to the repressor molecule (repressor m RNA) and thus preventing the repressor molecule from binding with lac operon. Since operon is free from binding, the RNA polymerase can easily bind to the operator region and transcribes the operon.
After some time due to continuous use of lactose by cells, decreases its quantity. Eventually, in the absence of lactose, the repressor molecule (m RNA) can easily bind with the operator region and thereby transcribing the operon. This shuts down the operon.
The low-level expression of lac operon has to be present has to be present in a cell for all time for the lactose (the inducer) to enter the cells.
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