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Tryptophan binds to and activates the repressor proteins; the repressor proteins, in turn, bind to the operator, preventing transcription.

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The tryptophan operon is turned off in the presence of tryptophan because tryptophan acts as a corepressor. When tryptophan levels are high, it binds to the trp repressor protein. This trp-repressor complex then binds to the operator region of the operon, preventing RNA polymerase from transcribing the genes involved in tryptophan synthesis.

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Q: Why is the tryptophan operon turned off in the presence of tryptophan?
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The tryptophan operon is a repressible operon that is?

regulated by the availability of tryptophan. When tryptophan levels are high, tryptophan acts as a corepressor, binding to the repressor protein, which then binds to the operator, preventing gene transcription. This allows bacteria to conserve energy by only producing tryptophan when needed.


Difference between inducible and repressible operons?

Inducible operons are normally turned off but can be turned on by an inducer molecule, such as lactose in the lac operon. Repressible operons are typically turned on but can be turned off by a corepressor molecule, like tryptophan in the trp operon. The key difference is in their default state and the signal that controls their activity.


The tryptophan synthetase operon uses glucose to synthesize tryptophan Repressible operons such as this one are?

typically involved in anabolic pathways that synthesize essential molecules. When the end product is abundant, it acts as a corepressor to inhibit transcription. This regulatory mechanism ensures that resources are not wasted on unnecessary synthesis.


What turns the lac operon on and off?

The lac operon is turned on when lactose is present in the environment and glucose is scarce. This leads to the activation of the lac repressor protein, allowing the expression of genes involved in lactose metabolism. The lac operon is turned off when lactose is absent or glucose is abundant, which prevents the unnecessary expression of these genes.


What is a clue that the lac operon is on?

One clue that the lac operon is on is the presence of lactose in the environment. The lac operon is induced when lactose is available as a substrate for the lac repressor protein, allowing transcription of genes involved in lactose metabolism.

Related questions

The tryptophan operon is a repressible operon that is?

regulated by the availability of tryptophan. When tryptophan levels are high, tryptophan acts as a corepressor, binding to the repressor protein, which then binds to the operator, preventing gene transcription. This allows bacteria to conserve energy by only producing tryptophan when needed.


What is a repressible operon?

A repressible operon is a type of operon in bacteria where gene expression is usually active but can be turned off when a specific corepressor molecule binds to the repressor protein. This binding causes the repressor to bind to the operator region of the operon, blocking transcription and thus shutting down gene expression. An example of a repressible operon is the trp operon in E. coli, which is involved in tryptophan biosynthesis.


Difference between inducible and repressible operons?

Inducible operons are normally turned off but can be turned on by an inducer molecule, such as lactose in the lac operon. Repressible operons are typically turned on but can be turned off by a corepressor molecule, like tryptophan in the trp operon. The key difference is in their default state and the signal that controls their activity.


The tryptophan synthetase operon uses glucose to synthesize tryptophan Repressible operons such as this one are?

typically involved in anabolic pathways that synthesize essential molecules. When the end product is abundant, it acts as a corepressor to inhibit transcription. This regulatory mechanism ensures that resources are not wasted on unnecessary synthesis.


What turns the lac operon on and off?

The lac operon is turned on when lactose is present in the environment and glucose is scarce. This leads to the activation of the lac repressor protein, allowing the expression of genes involved in lactose metabolism. The lac operon is turned off when lactose is absent or glucose is abundant, which prevents the unnecessary expression of these genes.


What is a clue that the lac operon is on?

One clue that the lac operon is on is the presence of lactose in the environment. The lac operon is induced when lactose is available as a substrate for the lac repressor protein, allowing transcription of genes involved in lactose metabolism.


What acts as an on and off switch in an operon?

which part of an operon acts as the on or off switch?


A lac repressor turns off the lac genes by binding to?

When the lac repressor binds to the O region, RNA polymerase is prevented from beginning the process of transcription. In effect, the binding of the repressor protein turns the operon "off" by preventing the transcription of its genes. (Prentice Hall Biology Book .....Chapter 12 page 310)


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 turns the lac operon off and off?

Repressors


Why lac operon the gene expression is switch off?

explain the regulation of gene expression in lac operon.


The lac operon is shut off when what is absent?

The lac operon is shut off when lactose is absent. In the absence of lactose, the repressor protein binds to the operator site, preventing transcription of the lac operon genes.