Search results
Results from the WOW.Com Content Network
The lactose operon (lac operon) is an operon required for the transport and metabolism of lactose in E. coli and many other enteric bacteria.Although glucose is the preferred carbon source for most enteric bacteria, the lac operon allows for the effective digestion of lactose when glucose is not available through the activity of β-galactosidase. [1]
You are free: to share – to copy, distribute and transmit the work; to remix – to adapt the work; Under the following conditions: attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses ...
Penguin diagram: a quark changes flavor via a W or Z loop Tadpole diagram: One loop diagram with one external leg Self-interaction or oyster diagram An electron emits and reabsorbs a photon Box diagram The box diagram for kaon oscillations: Photon-photon scattering: Higgs boson production: Via gluons and top quarks: Via quarks and W or Z bosons ...
The Feynman diagrams are much easier to keep track of than "old-fashioned" terms, because the old-fashioned way treats the particle and antiparticle contributions as separate. Each Feynman diagram is the sum of exponentially many old-fashioned terms, because each internal line can separately represent either a particle or an antiparticle.
The lac repressor (LacI) is a DNA-binding protein that inhibits the expression of genes coding for proteins involved in the metabolism of lactose in bacteria. These genes are repressed when lactose is not available to the cell, ensuring that the bacterium only invests energy in the production of machinery necessary for uptake and utilization of ...
In E. coli, the lacZ gene is the structural gene for β-galactosidase; which is present as part of the inducible system lac operon which is activated in the presence of lactose when glucose level is low. β-Galactosidase synthesis stops when glucose levels are sufficient. [2] β-Galactosidase has many homologues based on similar sequences.
The promoters used for these vector are usually based on the promoter of the lac operon or the T7 promoter, [11] and they are normally regulated by the lac operator. These promoters may also be hybrids of different promoters, for example, the Tac-Promoter is a hybrid of trp and lac promoters. [12]
Like allolactose, IPTG binds to the lac repressor and releases the tetrameric repressor from the lac operator in an allosteric manner, thereby allowing the transcription of genes in the lac operon, such as the gene coding for beta-galactosidase, a hydrolase enzyme that catalyzes the hydrolysis of β-galactosides into monosaccharides.