Edited Invalid date
13.1 Prokaryotic Regulation
Some genes were turned on or off in high-ranking females, compared to low-ranking females.
The study with the macaques shows that there are many factors that regulate when and how DNA can be transcribed.
Social status can affect the expression of genes for female macaques.
Gene expression is the translation of information from one part of the body to another.
Gene expression needs to be controlled or regulated, and there are many mechanisms that do this.
bacteria don't always need to express their entire complement of enzymes and proteins because their environment is always changing The L. "works" model was proposed by Jacob and Monod.
In 1965, they were awarded a prize for their work.
The operon is controlled by the repressor.
The promoter is a short sequence of DNA.
A promoter signals the start of the operon.
There is a small portion of DNA before the structural genes.
If a repressor is not attached to the operator, then transcription can occur.
The operator controls the transcription of structural genes.
These genes are involved in the metabolism of the operon.
Structural genes of the operon are normally expressed and the promoter can bind to the RNA polymerase.
Their products are part of a pathway that leads to the synthesis of the amino acid tryptophan.
Normally inactive, the regulatory gene codes for a repressor.
Structural genes are expressed when tryptophan is not present.
The shape of the repressor is changed when the tryptophan is present.
The operator can be bound by the repressor.
Structural genes are not expressed and the promoter can't be attached.
If tryptophan is present in the medium, the cell doesn't need the operon and it's turned off by the following method.
Tryptophan binding to the repressor.
The shape of the repressor now allows it to bind to the operator and prevent the polymerase from binding to the promoter.
A substance needs to be synthesised by the cell through the use of repressible operons.
Structural genes are expressed inbacteria, if they are needed for metabolism.
Genes are not expressed if metabolism is not required.
If the milk sugar is not present, there is no need for the expression of genes involved in catabolism.
When only Lactose is present, the cell begins to make the threeidases needed for metabolism.
The repressor is normally active.
Structural genes are not expressed when it binding to the operator.
When lactose is present, it changes its shape so that it can't bind to the operator.
Structural genes are expressed when the RNA polymerase binding to the promoter is successful.
Three structural genes are adjacent to one another and are under the control of a single promoter and a single operator.
Lactose binding to the repressor and the change in shape of the repressor are prevented when only Lactose is present.
The repressor is unable to bind to the operator, so the polymerase is better able to bind to the promoter.
The three enzymes of Lactose metabolism are made.
In catabolic pathways, operons are usually found.
The enzymes need to be active when the food is available.
The bacterium can make sure that the lactose operon is turned on only when there is no sugar in the air.
When CAP binding to DNA, the promoter is exposed.
CAP becomes active when cAMP is present.
Lactose is being transcribed, and it is being metabolized.
CAP is inactive if the promoter is present.
There is little cAMP in the cell, CAP is inactive, and the lactose operon is not functioning maximally.
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