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Is the lac operon found in prokaryotes or eukaryotes?
The lac operon is found in prokaryotes, specifically in bacteria such as Escherichia coli. It is a regulatory system that controls the expression of genes involved in lactose metabolism. Eukaryotic cells do not typically have operons like the lac operon.
What must happen for transcription of the lac operon genes to take place?
Lac operon is a set of genes that regulates the digestion of lactose. In absence of lactose in the medium, the repressor protein binds to the operator that inhibit the transcription of structural genes such as beta galactosidase, lactose permease and transacetylase. This makes sure to avoid the enzyme synthesis when there is no need!Conversely, when the lactose present in the medium, an isomer of lactose called allolactose bind to the repressor protein, the conformational change in the repressor let it to detach from repressor hence the RNA polymerase can transcribe the structural gene. Although this may be enough for synthesis of structual gene the system is tightly regulated by a protein called CAP (catabolite activator protein) and glucose.Glucose is a preferred source of energy for cell when this desirable source is present, lactose need not be used as a energy resource. What happens is there will be low level of cAMP when there is high amount of glucose and this keeps CAP inactive.When there is low glucose levels, the cAMP would be higher, that binds to CAP to make it active, which in turn binds to the promoter that enhance the transcription of structural genes.Thus, for efficient transcription lac operon structural genes, lactose must be present where glucose must be absent.
The lac repressor releases the operator in the presence of glucose?
That statement is inaccurate. The lac repressor releases the operator in the absence of glucose but in the presence of lactose. Glucose acts as a catabolite activator protein (CAP) regulator in the lac operon system.
What is the mechanism by which the presence of glucose inhibits the lac operon?
The mechanism by which the presence of glucose inhibits the arabinose operon is catabolite repression. The lac operon is responsible for the metabolism of glucose.
Where does Lactose metabolism occur in the human body?
Lactose metabolism primarily occurs in the small intestine. Enzymes called lactase are responsible for breaking down lactose into its simpler forms, glucose and galactose, which can then be absorbed by the body for energy. If lactase is deficient, individuals may experience lactose intolerance.
When is gene expression blocked in the lac operon system?
Gene expression is blocked in the lac operon system when the lac repressor binds to the operator in the presence of lactose. This prevents RNA polymerase from transcribing the genes, keeping the system off until lactose is available to derepress the operon.
What is the comparison between lac operon and trp operon?
The lac operon and trp operon are both key regulatory mechanisms in bacteria that control gene expression in response to environmental conditions. The lac operon, which is involved in lactose metabolism, is activated in the presence of lactose and inhibited by glucose, functioning primarily through an inducible system. In contrast, the trp operon regulates tryptophan biosynthesis and operates as a repressible system, being turned off when tryptophan levels are sufficient. Thus, while the lac operon responds to the availability of substrates, the trp operon responds to the abundance of end products.
Is the lac operon found in prokaryotes or eukaryotes?
The lac operon is found in prokaryotes, specifically in bacteria such as Escherichia coli. It is a regulatory system that controls the expression of genes involved in lactose metabolism. Eukaryotic cells do not typically have operons like the lac operon.
How can you describe the state of the lac operon system if the level of lactose is low indicating the activity and state of all major enzymes and proteins found in the system?
http://en.wikipedia.org/wiki/Lac_operon
What does the promoter of the lac operon sac do?
The promoter of the lac operon helps initiate the transcription of the lac genes. It is where RNA polymerase binds to start transcribing the mRNA for the lacZ, lacY, and lacA genes. The Lac operon is a system in bacterial cells that regulates the expression of genes involved in lactose metabolism.
What is the role of lactose in regulating lac operon expression?
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.
What must happen for transcription of the lac operon genes to take place?
Lac operon is a set of genes that regulates the digestion of lactose. In absence of lactose in the medium, the repressor protein binds to the operator that inhibit the transcription of structural genes such as beta galactosidase, lactose permease and transacetylase. This makes sure to avoid the enzyme synthesis when there is no need!Conversely, when the lactose present in the medium, an isomer of lactose called allolactose bind to the repressor protein, the conformational change in the repressor let it to detach from repressor hence the RNA polymerase can transcribe the structural gene. Although this may be enough for synthesis of structual gene the system is tightly regulated by a protein called CAP (catabolite activator protein) and glucose.Glucose is a preferred source of energy for cell when this desirable source is present, lactose need not be used as a energy resource. What happens is there will be low level of cAMP when there is high amount of glucose and this keeps CAP inactive.When there is low glucose levels, the cAMP would be higher, that binds to CAP to make it active, which in turn binds to the promoter that enhance the transcription of structural genes.Thus, for efficient transcription lac operon structural genes, lactose must be present where glucose must be absent.
The lac repressor releases the operator in the presence of glucose?
That statement is inaccurate. The lac repressor releases the operator in the absence of glucose but in the presence of lactose. Glucose acts as a catabolite activator protein (CAP) regulator in the lac operon system.
What is the mechanism by which the presence of glucose inhibits the lac operon?
The mechanism by which the presence of glucose inhibits the arabinose operon is catabolite repression. The lac operon is responsible for the metabolism of glucose.
In what organ does lactose intolerance occur?
Lactose Intolerance occurs in the digestive system.
What is lactate tolerance?
Lactose intolerance is the inability to metabolize lactose, because of a lack of the required enzyme lactase in the digestive system.
How do you become lactose intolerance?
Lactose intolerance occurs when the digestive system is no longer able to metabolise the sugars (lactose) found in dairy products through producing insufficient amounts of an enzyme called lactase.
