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How is a non-constituative gene turned off?
repressor proteins block the gene physically and prevent transcription from occurring
When lactose is present in bacterial does it prevent the blocking effect of the repressor protein and allow the transcription of lactose metabolizing genes?
Yes. A precursor to lactose binds to the repressor and prevents or relaxes its binding to the Lac operon.
What state is the repressor protein in when tryptophan is absent?
When tryptophan is absent, the repressor protein is in an inactive state, allowing transcription of the trp operon to continue. This is because the repressor protein needs tryptophan to bind to it, enabling it to attach to the operator region and block transcription of the operon.
How would RNA polymerase be affected if the repressor protein were not bound to the proper site on a gene?
If the repressor protein is not bound to the proper site on a gene, it would not block the RNA polymerase from transcribing the gene. This would lead to the expression of the gene, as the RNA polymerase can then proceed with transcription.
The expression of the tryptophan operon is controlled by?
The expression of the tryptophan operon is controlled by a repressor protein that binds to the operator region in the presence of tryptophan. When tryptophan levels are high, the repressor is active and prevents transcription of the operon. When tryptophan levels are low, the repressor is inactive, allowing transcription to occur.
A protein that binds to an operator and inhibits transcription?
A repressor protein binds to the operator region of DNA to inhibit the binding of RNA polymerase, blocking transcription of the gene. This mechanism is common in prokaryotic organisms to regulate gene expression by preventing transcription of specific genes when they are not needed.
What turns off transcription by binding to the operator?
A repressor protein turns off transcription by binding to the operator region. By binding to the operator, the repressor prevents the RNA polymerase from binding to the promoter region and initiating transcription. This prevents the expression of the gene or genes downstream of the operator.
Transcription of lactose-metabolizing genes is blocked when?
Transcription of lactose-metabolizing genes is blocked when the Lac repressor protein binds to the operator region of the lac operon. This typically occurs in the presence of glucose when lactose is absent or in low concentrations. The Lac repressor prevents RNA polymerase from transcribing the genes, leading to inhibition of lactose metabolism.
What happens when a repressor is bound to the operator?
When a repressor is bound to the operator, it physically blocks the RNA polymerase from binding to the promoter region of the gene, preventing transcription. This mechanism effectively shuts down gene expression by inhibiting the initiation of transcription of that specific gene.
The operon segment composed of the gene that codes for a protein repressor is called the?
The operon segment composed of the gene that codes for a protein repressor is called the regulatory gene. This gene produces the repressor protein that can bind to the operator region of the operon, preventing transcription of the structural genes when the repressor is bound.
What is the difference between a repressor and an activator in gene regulation?
In gene regulation, a repressor is a protein that blocks the expression of a gene, while an activator is a protein that enhances the expression of a gene. Repressors prevent the binding of RNA polymerase to the gene, while activators help RNA polymerase bind to the gene and initiate transcription.
How is the ath operon most likely controlled?
The ath operon is most likely controlled by a repressor protein that binds to the operator region to prevent transcription. This repressor protein may undergo conformational changes in response to the presence of aromatic amino acids, allowing for the expression of the operon when these amino acids are scarce.
