Q15 of 30 Page 1

How would lac operon operate in E. coli growing in a culture medium where lactose is present as source of sugar?

When lactose is present , the lac genes are expressed because allolactose binds to the lac repressor protein and keeps it from binding to the lac operator.


Allolactose is an isomer of lactose. Small amount of allolactose are formed when lactose enters E. coli.


In the absence of glucose, if lactose is added on the growth medium of the bacteria, the lactose is transported into the cell by permease.


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