regulatory promoter oerator
It is always transcribed.
it will prevent the transcription of rNA polymerase
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.
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.
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)
It is always transcribed.
RNA polymerase.
it will prevent the transcription of rNA polymerase
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.
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.
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 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.
A repressor, which works by binding to the operator and blocking the attachment of RNA polymerase to the promoter.
A repressor, which works by binding to the operator and blocking the attachment of RNA polymerase to the promoter
False: its An Repressor not an enhancer
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)
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.