Question

1. Describe and draw the lactose operon.

Answer 1

As we know that is In genetics, an operon is a functioning unit of DNA containing a cluster of genes under the control of a single promoter.The genes are transcribed together into an mRNA strand and either translated together in the cytoplasm, or undergo splicing to create monocistronic mRNAs that are translated separately, i.e. several strands of mRNA that each encode a single gene product .so it is The lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria. ans it also work in the  body

Lactase is a protein, an enzyme that is produced in the small intestine. The human body uses lactase to break down lactose into galactose and glucose, which is then absorbed into the bloodstream. If lactase levels are low, the lactose does not break down and it does not absorb into the bloodstream.

Regulation of the Lactose SystemThe salient features of transcriptional regulation in prokaryotes can be seen in the regulation of expression of the enzymes necessary for lactose metabolism in the bacterium Escherichia coli

The lac Structural Genes

The metabolism of lactose requires two enzymes: a permease to transport lactose into the cell and β-galactosidase to cleave the lactose molecule to yield glucose and galactose

Catabolite Repression of the lac Operon: Choosing the Best Sugar to Metabolize

An additional control system is superimposed on the repressor–operator system. This control system is thought to have evolved because the cell can capture more energy from the breakdown of glucose than it can from the breakdown of other sugars. If both lactose and glucose are present, the synthesis of β-galactosidase is not induced until all the glucose has been utilized.