When the lac operon controls the expression of proteins in the E.coli cell that can break down lactose into two sugars, glucose and galactose.
When lactose is present, it binds to the repressor that typically sits on the lac operon, changing the repressor's conformation such that it can no longer bind to the lac operon. Because of this, RNA polymerase can now transcribe the gene into mRNA, which in turn is translated into the proteins that can break down lactose.
My answer is 3, I am pretty sure I am right, but I would double check to make sure. I am in ninth grade taking biology at PineTree.
t68u56r3
it is by lac operon syastem
The lac operon is switched on so the E. coli can use it as a food source.
gene expression occurring at transcription
When the lac operon controls the expression of proteins in the E.coli cell that can break down lactose into two sugars, glucose and galactose. When lactose is present, it binds to the repressor that typically sits on the lac operon, changing the repressor's conformation such that it can no longer bind to the lac operon. Because of this, RNA polymerase can now transcribe the gene into mRNA, which in turn is translated into the proteins that can break down lactose.
E. coli binds with lactose which changes its conformation so that it no longer binds to DNA. This allows the lactose operon to be transcribed.
The DNA sequence located near the promoter of the lactose operon in E. coli that regulates its expression is called the lac operator. The lac operator binds the lac repressor protein, which inhibits transcription of the operon when lactose is absent. When lactose is present, it binds to the repressor, causing it to release from the operator and allowing transcription to proceed.
The molecule that typically causes transcription of an operon is an inducer, which can either activate or repress the operon by binding to a regulatory protein. In the case of an inducible operon like the lac operon in E. coli, lactose acts as an inducer by binding to the repressor protein and preventing it from blocking transcription.
The lac genes in E. coli are regulated by the lac operon, which is controlled by a repressor protein. The repressor binds to the operator region of the DNA, blocking the transcription of the lac genes. When lactose is present, it binds to the repressor, causing a conformational change that releases the repressor from the operator, allowing for the expression of the lac genes.
trp operon
The lac operon is a place on the DNA that binds to the DNA to stop the production of the RNA sequence to code for lactase (breaks down lactose) or binds to lactase to let the production of the RNA sequence to proceed.