Search results
Results from the WOW.Com Content Network
The lactose operon (lac operon) is an operon required for the transport and metabolism of lactose in E. coli and many other enteric bacteria.Although glucose is the preferred carbon source for most enteric bacteria, the lac operon allows for the effective digestion of lactose when glucose is not available through the activity of β-galactosidase. [1]
The lac operon of the model bacterium Escherichia coli was the first operon to be discovered and provides a typical example of operon function. It consists of three adjacent structural genes, a promoter, a terminator, and an operator. The lac operon is regulated by several factors including the availability of glucose and lactose.
When these two conditions are satisfied, it means for the bacteria that glucose is absent and lactose is available. Next, bacteria start to transcribe the lac operon and produce β-galactosidase enzymes for lactose metabolism. The example above is a simplification of a complex process.
The lac operon in the prokaryote E. coli consists of genes that produce enzymes to break down lactose. Its operon is an example of a prokaryotic silencer. The three functional genes in this operon are lacZ, lacY, and lacA. [6] The repressor gene, lacI, will produce the repressor protein LacI which is under allosteric regulation.
Monod's interest in the lac operon originated from his doctoral dissertation, which explored the growth of bacteria on mixtures of sugars and documented the sequential utilization of two or more sugars. [9] [11] [12] The work was conducted at the University of Paris, with André Lwoff of the Pasteur Institute having provided important advice. [13]
It is encoded by the lacY gene in the lac operon. The LacY gene is a component of the lac operon that encodes lactose permease, a protein responsible for breaking down lactose into glucose and galactose, alongside transacetylase and beta galactosidase.
Food poisoning, also known as foodborne illness, is a common sickness caused by swallowing food or liquids that contain harmful bacteria, viruses or parasites, and sometimes even chemicals.
The lac repressor (LacI) is a DNA-binding protein that inhibits the expression of genes coding for proteins involved in the metabolism of lactose in bacteria. These genes are repressed when lactose is not available to the cell, ensuring that the bacterium only invests energy in the production of machinery necessary for uptake and utilization of ...