What is the significance of lac operon?

The classic example of prokaryotic gene regulation is that of the lac operon. This operon is a genetic unit that produces the enzymes necessary for the digestion of lactose (Fig. 16-13). The lac operon consists of three contiguous structural genes that are transcribed as continuous mRNA by RNA polymerase.

What activates the lac operon?

The lac operon is an inducible operon that utilizes lactose as an energy source and is activated when glucose is low and lactose is present.

What role does cAMP play in the regulation of the lac operon quizlet?

How does cAMP play a role in the transcription of the lac operon? cAMP binds to CAP and together they bind to the DNA, which enhances transcription of the lac operon.

Why does the lac operon switch off after some time?

After addition of lactose complete breakdown of lactose to glucose and galactose takes place. Therefore there is no more lactose to bind to the repressor protein and the lac operon shuts down.

How does a lac repressor turn off Lac genes?

Glucose and lactose levels control the initiation of transcription of the lac operon through their effects on the lac repressor protein and CAP. Lactose addition increases the concentration allolactose, which binds to the repressor protein and removes it from the DNA.

What is the lac operon and how is it controlled?

The lac operon is a negatively controlled inducible operon, where the inducer molecule is allolactose. In negative repressible operons, transcription of the operon normally takes place. Repressor proteins are produced by a regulator gene, but they are unable to bind to the operator in their normal conformation.

What is the function of the lac operator?

Lac operator. 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.

What regulates the lac operon?

Lac Repressor. The lac repressor refers to a lactose sensor,which blocks the transcription of the lac operon in the presence of glucose.

What is the function of the genes in the lac operon?

The lac operon is an operon, or group of genes with a single promoter (transcribed as a single mRNA). The genes in the operon encode proteins that allow the bacteria to use lactose as an energy source.