Examples of using Operon in English and their translations into Vietnamese
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For example, T7 phages have two operons.
Operons are related to regulons, stimulons and modulons;
The genome encodes 200-300 proteins that are transcribed in operons.
Operons are also found in viruses such as bacteriophages.
The number and organization of operons has been studied most critically in E. coli.
The regulatory gene does not need to be in, adjacent to,or even near the operon to control it.
Longer stretches exist where operons start and stop, often up to 40- 50 bases.
The lac operon is regulated by several factors including the availability of glucose and lactose.
A single unit of messenger RNA(mRNA) is transcribed from the operon and is subsequently translated into separate proteins.
In the absence of lactose, the lac repressor, lacI,halts production of the enzymes encoded by the lac operon.
The 517 polycistronic operons are listed in a 2009 study describing the global changes in transcription that occur in L.
It is not possible to talk of a general regulatory mechanism,because different operons have different mechanisms.
In genetics, an operon is a functioning unit of DNA containing a cluster of genes under the control of a single promoter.
Used in conjunction with X-Gal or Bluo-Gal in blue-white selection of recombinantbacterial colonies that induce expression of the lac operon in Escherichia coli.
For example, an operon is a stretch of DNA that is transcribed to create a contiguous segment of RNA, but contains more than one cistron/ gene.
The importance of Barbara's contributions came to light only when the French Francois Jacob andJacques Monod's work in 1960 described the genetic regulation of lac operon, a concept that Barbara had demonstrated with her Ac/Ds in 1951.
In negative inducible operons, a regulatory repressor protein is normally bound to the operator, which prevents the transcription of the genes on the operon.
The protein assumes its active shape and binds to a specific site beside the lac promoter, making it easier for RNA polymerase to bind to the adjacent promoter to start transcription of the lac operon, increasing the rate of lac operon transcription.
The lac operon of the model bacterium Escherichia coli was the first operon to be discovered and provides a typical example of operon function.
Although glucose is the preferred carbon source for most bacteria,the lac operon allows for the effective digestion of lactose when glucose is not available through the activity of beta-galactosidase.
Elegans operons also differ from those in bacteria in that each pre-mRNA is processed into a separate mRNA for each gene rather than being translated as a unit.
Following Jacob and Monod's 1961 Journal of Molecular Biology paper"Genetic regulatory mechanisms in the synthesis of proteins",McClintock wrote an article for American Naturalist comparing the lac operon and her work on controlling elements in maize.
While the lac operon can be activated by a chemical(allolactose), the tryptophan(Trp) operon is inhibited by a chemical(tryptophan).
This theory suggested that in all cases, genes within an operon are negatively controlled by a repressor acting at a single operator located before the first gene.
Whereas operons contain a set of genes regulated by the same operator, regulons contain a set of genes under regulation by a single regulatory protein, and stimulons contain a set of genes under regulation by a single cell stimulus.
An alternative method to predict operons is based on finding gene clusters where gene order and orientation is conserved in two or more genomes.[18].
The lac operon is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria.
Not always included within the operon, but important in its function is a regulatory gene, a constantly expressed gene which codes for repressor proteins.
The lac operon uses a two-part control mechanism to ensure that the cell expends energy producing the enzymes encoded by the lac operon only when necessary.
