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---|CRP|-------------| O |---| Z | Y | A |---

CRP: Binding site for activator

O: Operator, binding site for repressor

Coding sequences:

Z: b-galactosidase

Y: lactose permease

A: thiogalactoside transacetlyase

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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.


When does the induction of the lac operon occur?

The induction of the lac operon occurs when lactose is present in the environment and glucose is limited. The presence of lactose leads to the activation of the lac repressor protein, allowing RNA polymerase to bind to the promoter region and transcribe the genes involved in lactose metabolism.


Four of the five answers listed below are features of the lactose operon Select the exception a regulator b terminator c operator d promoter e structural gene?

The "lac operon" is the unit of DNA in E.coli and other bacteria which is responsible for the metabolism of lactose. So with regards to the question above, its function is that of an operator.


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.


When is the lactose operon likely to be transcribed?

The lactose operon is likely to be transcribed in the absence of glucose and presence of lactose. When glucose is low and lactose is available, the inducer molecule allolactose binds to the repressor protein, causing it to be released from the operator region and enabling RNA polymerase to transcribe the operon.

Related Questions

The operon that controls the metabolism of lactose is called the what?

its an operon required for the transport and metabolism of lactose.


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.


If lactose is present would the lac operon in a bacterial cell be on or off?

If lactose is present, the lac operon in a bacterial cell would be "on." Lactose binds to the repressor protein, causing it to change shape and detach from the operator region of the operon. This allows RNA polymerase to access the promoter and initiate transcription of the genes needed for lactose metabolism. Therefore, the presence of lactose activates the operon.


When does the induction of the lac operon occur?

The induction of the lac operon occurs when lactose is present in the environment and glucose is limited. The presence of lactose leads to the activation of the lac repressor protein, allowing RNA polymerase to bind to the promoter region and transcribe the genes involved in lactose metabolism.


True are false the lac operon is a repressible operon?

False. The lac operon is an inducible operon, not a repressible one. It is typically turned off when lactose is absent and activated when lactose is present, allowing the transcription of genes needed for lactose metabolism. In contrast, repressible operons are usually active and can be turned off by the presence of a specific molecule.


How does lactose caue the lac opero to turn on?

Lactose activates the lac operon by binding to the repressor protein, which normally inhibits the operon by blocking transcription. When lactose is present, it is converted into allolactose, which binds to the repressor, causing a conformational change that releases it from the operator region of the operon. This removal allows RNA polymerase to access the promoter and initiate transcription of the genes needed for lactose metabolism. Consequently, the lac operon is turned on in the presence of lactose.


Four of the five answers listed below are features of the lactose operon Select the exception a regulator b terminator c operator d promoter e structural gene?

The "lac operon" is the unit of DNA in E.coli and other bacteria which is responsible for the metabolism of lactose. So with regards to the question above, its function is that of an operator.


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.


When is the lactose operon likely to be transcribed?

The lactose operon is likely to be transcribed in the absence of glucose and presence of lactose. When glucose is low and lactose is available, the inducer molecule allolactose binds to the repressor protein, causing it to be released from the operator region and enabling RNA polymerase to transcribe the operon.


Why is the lac operon not transcribed when both glucose and lactose are present in the medium?

The lac operon is not transcribed when both glucose and lactose are present because glucose is the preferred energy source for the cell. When glucose is available, the lac operon is repressed, preventing the cell from wasting energy by metabolizing lactose.


What environmental factor causes the lac operon to turn on?

In the lac operon model, lactose acts as in inducer molecule. In the presence of lactose, the molecule binds to the repressor protein. This repressor-lactose complex is unable to bind to the promoter. When the promoter is not occupied, RNA pol - II binds to it and begins transcribing the structural genes located downstream. Thus, the lac operon is turned on in the presence of lactose.


What happen to lac repressor in E. coli when lactose is present?

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.