<P> The lac operon ( lactose operon ) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria . Although glucose is the preferred carbon source for most bacteria , the lac operon allows for the effective digestion of lactose when glucose is not available through the activity of beta - galactosidase . Gene regulation of the lac operon was the first genetic regulatory mechanism to be understood clearly , so it has become a foremost example of prokaryotic gene regulation . It is often discussed in introductory molecular and cellular biology classes for this reason . This lactose metabolism system was used by Jacob and Monod to determine how a cell knows which enzyme to synthesize . Their work on the lac operon won them the Nobel Prize in Physiology in 1965 . </P>
<P> The lac operon ( lactose operon ) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria . Although glucose is the preferred carbon source for most bacteria , the lac operon allows for the effective digestion of lactose when glucose is not available through the activity of beta - galactosidase . Gene regulation of the lac operon was the first genetic regulatory mechanism to be understood clearly , so it has become a foremost example of prokaryotic gene regulation . It is often discussed in introductory molecular and cellular biology classes for this reason . This lactose metabolism system was used by Jacob and Monod to determine how a cell knows which enzyme to synthesize . Their work on the lac operon won them the Nobel Prize in Physiology in 1965 . </P>
in prokaryotes the lac operon contains gene ( s ) for
in prokaryotes the lac operon contains gene ( s ) for
lactose
lactose