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In Figure 84 which model of the lac operon correctly shows RNA polymerase lactose and repressor protein when the structural genes are being transcribed?
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∙ 11y ago
regulatory promoter oerator
Wiki User
∙ 11y ago
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When is the repressor protein transcribed?
It is always transcribed.
How would RNA polymerase be affected if the repressor protein were not bound to the proper site on a gene?
it will prevent the transcription of rNA polymerase
What is the operon hypothesis and discuss how it explains the control of?
control of messenger RNA production? An operon is made up of a promoter, structural genes, and the operator. The operator is basically the on-off switch for DNA polymerase. Transcription relies on the cell's regulator, which codes for a repressor that bind to the operator. When the repressor binds to the operator, the promoter is blocked. Thus, preventing transcription to occur. However, an inducer can activate or deactivate the repressor. When deactivated, RNA polymerase can bind to the DNA molecule to begin transcription.
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.
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 the repressor protein transcribed?
It is always transcribed.
The presence of a repressor protein prevents the action of what enzyme?
RNA polymerase.
How would RNA polymerase be affected if the repressor protein were not bound to the proper site on a gene?
it will prevent the transcription of rNA polymerase
What is the operon hypothesis and discuss how it explains the control of?
control of messenger RNA production? An operon is made up of a promoter, structural genes, and the operator. The operator is basically the on-off switch for DNA polymerase. Transcription relies on the cell's regulator, which codes for a repressor that bind to the operator. When the repressor binds to the operator, the promoter is blocked. Thus, preventing transcription to occur. However, an inducer can activate or deactivate the repressor. When deactivated, RNA polymerase can bind to the DNA molecule to begin transcription.
How is the trp repressor protein and allosteric protein?
If Tryptophan is low in the diet, the repressor changes shape and allows the RNA polymerase to attach and copy the DNA so that Tryptophan can be produced by the cell.
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 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.
Examples of a molecule in your body that can affect transcription factors?
A repressor, which works by binding to the operator and blocking the attachment of RNA polymerase to the promoter.
Give an examples of a molecule in your body that can affect transcription factors?
A repressor, which works by binding to the operator and blocking the attachment of RNA polymerase to the promoter
Is an enhancer is a sequence of nucleotides that when activated by specific signal proteins aids in shielding the RNA polymerase binding site of a specific gene?
False: its An Repressor not an enhancer
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 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.
