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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.
What is fuction of operator region in operon?
The operator region in an operon functions as a regulatory switch that controls the transcription of the associated genes. It is a specific DNA sequence where repressor proteins can bind, inhibiting RNA polymerase from initiating transcription. When a repressor is bound to the operator, gene expression is turned off; conversely, when the repressor is absent or inactivated, transcription can proceed, allowing the genes to be expressed. This mechanism is crucial for the efficient regulation of gene expression in prokaryotic cells.
In E. coli the tryprophan switches off the trp operon by?
binding to the trp repressor, causing a conformational change that allows it to bind to the operator region of the trp operon. This blocks RNA polymerase from transcribing the genes, turning off expression of the trp operon.
Can eukaryotic Cells control gene expression by using transcription factors?
Yes, eukaryotic cells can control gene expression using transcription factors. Transcription factors are proteins that regulate the transcription of specific genes by binding to DNA and either promoting or inhibiting gene expression. They play a crucial role in controlling when and where genes are turned on or off in response to various signals and cellular conditions.
What is sometimes turned off by regulatory proteins that bind to DNA and block transcription?
Regulatory proteins that bind to DNA and block transcription are often referred to as repressors. These proteins can inhibit the expression of specific genes by physically obstructing the binding of RNA polymerase or other transcription factors to the promoter region of the gene. By doing so, they effectively prevent the transcription of mRNA, thereby regulating gene expression in response to various cellular signals or environmental conditions.
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)
What causes the lac genes in E. coli to turn off?
A lac repressor turns off the lac genes by binding to the operator.
A lac repressor turns ff the lac genes by binding to?
A lac repressor turns off the lac genes by binding to the operator
What Piece of DNA that serves as an on-off switch for transcription?
The operator
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.
What is fuction of operator region in operon?
The operator region in an operon functions as a regulatory switch that controls the transcription of the associated genes. It is a specific DNA sequence where repressor proteins can bind, inhibiting RNA polymerase from initiating transcription. When a repressor is bound to the operator, gene expression is turned off; conversely, when the repressor is absent or inactivated, transcription can proceed, allowing the genes to be expressed. This mechanism is crucial for the efficient regulation of gene expression in prokaryotic cells.
In E. coli the tryprophan switches off the trp operon by?
binding to the trp repressor, causing a conformational change that allows it to bind to the operator region of the trp operon. This blocks RNA polymerase from transcribing the genes, turning off expression of the trp operon.
How do repressors affect promoters?
a repressor is a protein that binds to DNA, which turns off the genes that code for the digestive enzymes. the promoter, located near the digestive enzyme genes, is a section on DNA that serves as the binding site for the enzyme RNA polymers.
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.
Can eukaryotic Cells control gene expression by using transcription factors?
Yes, eukaryotic cells can control gene expression using transcription factors. Transcription factors are proteins that regulate the transcription of specific genes by binding to DNA and either promoting or inhibiting gene expression. They play a crucial role in controlling when and where genes are turned on or off in response to various signals and cellular conditions.
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.
What does it mean for a gene to be turned off or not expressed?
When a gene is turned off or not expressed, it means that the DNA sequence within that gene is not being transcribed into mRNA and translated into protein. This can happen through a variety of mechanisms that regulate gene expression, such as DNA methylation, histone modification, and transcription factor binding.
