Endergonic means absorbing energy in the form of work. Its etymology stems from the suffix "-ergonic" as derived from the Greek root "ergon" meaning work, combined with the prefix "end-" as derived from the Greek root "en" meaning "put into". By thermodynamic standards, work, a form of energy, is defined normally to move from the surroundings (the external region) to the system (the internal region). Thus, an endergonic process, as contrasted with an exergonic process, is one where the system absorbs energy from the surroundings. Subsequently, during an endergonic process energy is "put into" the system. If the transformation occurs at constant pressure and temperature: "∆G > 0". An endergonic reaction is a chemical reaction that absorbs energy in the form of work. A good example of an endergonic reaction is photosynthesis.

An endergonic reaction is essentially the opposite of an exergonic reaction. Since endergonic reactions require energy, they form molecular bonds, which decreases entropy. These bonds are energy carriers, so the formation of these bonds requires some energy input.

'Cold packs,' which become cold after mixing two liquids, exploit this property. In fact, a common reaction which is clearly endergonic is the mixing of ammonium chloride and water. There is a net drop in temperature of the reaction as a result of the solvation of Ammonium ion.

ee also

*Exergonic reaction
*Exothermic reaction
*Endothermic reaction

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Look at other dictionaries:

  • endergonic — [en΄dər gän′ik] adj. of or having to do with a biochemical reaction requiring the absorption of energy, as photosynthesis or anabolism: opposed to EXERGONIC …   English World dictionary

  • endergonic — adjective Etymology: end + Greek ergon work more at work Date: 1940 endothermic 1 < an endergonic biochemical reaction > …   New Collegiate Dictionary

  • endergonic — An endergonic reaction requires the input of energy …   Dictionary of molecular biology

  • endergonic — Referring to a chemical reaction that takes place with absorption of energy from its surroundings ( i.e., a positive change in Gibbs free energy). Cf.:exergonic. [endo + G. ergon, work] * * * end·er·gon·ic .en .dər gän ik adj …   Medical dictionary

  • endergonic — adjective (biochemistry) of a process accompanied by or requiring the absorption of energy; the products of the process are of greater free energy than the reactants photosynthesis is an endergonic process • Ant: ↑exergonic • Topics:… …   Useful english dictionary

  • endergonic — /en deuhr gon ik/, adj. Biochem. (of a biochemical reaction) requiring energy. Cf. exergonic. [1935 40; END + Gk érgon work + IC] * * * …   Universalium

  • endergonic — adjective Describing a reaction that absorbs (heat) energy from its environment …   Wiktionary

  • endergonic — end·er·gon·ic …   English syllables

  • endergonic — end•er•gon•ic [[t]ˌɛn dərˈgɒn ɪk[/t]] adj. biochem. (of a biochemical reaction) requiring energy Compare exergonic • Etymology: 1935–40 …   From formal English to slang

  • endergonic — /ɛndəˈgɒnɪk/ (say enduh gonik) adjective (of a chemical reaction) consuming energy or requiring energy to occur, as when the temperature of water being mixed with ammonium chloride drops. Compare exergonic. {end + Greek ergon work + ic} …   Australian English dictionary

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