In chemistry and biology , activation is the process whereby something is prepared or excited for a subsequent reaction .
13-468: [REDACTED] Look up activate in Wiktionary, the free dictionary. Activate may refer to: Arts and entertainment [ edit ] Activate (album) , by Back Door Activated (album) , by Tee Grizzley "Activate", a 2006 song by Stellar Kart from We Can't Stand Sitting Down " Activated ", a 2016 song by Cher Lloyd "Activated",
26-404: A molecule into a nearly identical chemical or physical state, with the defining characteristic being that this resultant state exhibits an increased propensity to undergo a specified chemical reaction . Thus, activation is conceptually the opposite of protection , in which the resulting state exhibits a decreased propensity to undergo a certain reaction. The energy of activation specifies
39-478: A 1989 song by Gerald Alston Organisations [ edit ] Activate (organisation) , a British political organisation Activate Learning , an English education group Honduras Activate , a health organisation See also [ edit ] Activation Activator (disambiguation) Reactivate , trance music compilation album series Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with
52-464: A British political organisation Activate Learning , an English education group Honduras Activate , a health organisation See also [ edit ] Activation Activator (disambiguation) Reactivate , trance music compilation album series Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Activate . If an internal link led you here, you may wish to change
65-479: Is called chemical kinetics . In biochemistry , activation, specifically called bioactivation , is where enzymes or other biologically active molecules acquire the ability to perform their biological function, such as inactive proenzymes being converted into active enzymes that are able to catalyze their substrates' reactions into products . Bioactivation may also refer to the process where inactive prodrugs are converted into their active metabolites, or
78-424: Is catalyzed by aminoacyl-tRNA synthetase , and requires a molecule of ATP . The amino acid bound to the tRNA is called an aminoacyl-tRNA , and is considered the activated molecule in protein translation. Once activated, the aminoacyl-tRNA may move to the ribosome and add the amino acid to the growing polypeptide chain. In immunology , activation is the transition of leucocytes and other cell types involved in
91-448: Is where a cofactor binds to an enzyme, which then remains active while the cofactor is bound, and stops being active when the cofactor is removed. In protein synthesis , amino acids are carried by transfer RNA (tRNA) molecules and added to a growing polypeptide chain on the ribosome . In order to transfer the amino acids to the ribosome, tRNAs must first be covalently bonded to the amino acid through their 3' CCA terminal. This binding
104-414: The toxication of protoxins into actual toxins. An enzyme may be reversibly or irreversibly bioactivated. A major mechanism of irreversible bioactivation is where a piece of a protein is cut off by cleavage, producing an enzyme that will then stay active. A major mechanism of reversible bioactivation is substrate presentation where an enzyme translocates near its substrate. Another reversible reaction
117-557: The immune system . On the other hand, deactivation is the transition in the reverse direction. This balance is tightly regulated, since a too small degree of activation causes susceptibility to infections, while, on the other hand, a too large degree of activation causes autoimmune diseases . Activation and deactivation results from a variety of factors, including cytokines , soluble receptors , arachidonic acid metabolites, steroids , receptor antagonists , adhesion molecules , bacterial products and viral products. Activation refers to
130-477: The amount of free energy the reactants must possess (in addition to their rest energy) in order to initiate their conversion into corresponding products —that is, in order to reach the transition state for the reaction. The energy needed for activation can be quite small, and often it is provided by the natural random thermal fluctuations of the molecules themselves (i.e. without any external sources of energy). The branch of chemistry that deals with this topic
143-492: The 💕 [REDACTED] Look up activate in Wiktionary, the free dictionary. Activate may refer to: Arts and entertainment [ edit ] Activate (album) , by Back Door Activated (album) , by Tee Grizzley "Activate", a 2006 song by Stellar Kart from We Can't Stand Sitting Down " Activated ", a 2016 song by Cher Lloyd "Activated", a 1989 song by Gerald Alston Organisations [ edit ] Activate (organisation) ,
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#1732791366144156-426: The link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Activate&oldid=1209008039 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Activation In chemistry , "activation" refers to the reversible transition of
169-458: The title Activate . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Activate&oldid=1209008039 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages activate From Misplaced Pages,
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