TERMIUM Plus^®

Record 1,  Textual support,  English

Record number: 1, Textual support number: 1 DEF

Linking of an exogonic reaction and an endogonic reaction in such a way that there is only a small net change in free energy, resulting in an overall reversible reaction. In living organisms, anabolic reactions are coupled with catabolic reactions resulting in the build up of complex molecules, but with an overall loss of energy as metabolic heat.  2, record 1, English, - coupled%20reaction

Record number: 1, Textual support number: 1 CONT

Coupling is brought about when an enzyme causes a substrate that is to be consumed ... to react with one of the cell's small-molecule energy donors (say, ATP) to give rise to an energized activated substrate molecule. The subsequent decomposition of this activated substrate in the synthetic reaction will release significant energy, which will result in the synthetic reaction .... The need for cells to carry on simultaneously many different coupled reactions requires cells to devote a significant part of their total metabolic activity to the constant replenishment of their ATP supply. In animal cells and in most bacteria, the formation of ATP is coupled with the breakdown of food molecules that are even more rich in energy. In cells that carry out photosynthesis, the energy of sunlight is used directly to make ATP.  3, record 1, English, - coupled%20reaction

Record 1,  Textual support,  French

Record number: 1, Textual support number: 1 CONT

Les cellules vivantes doivent effectuer un certain nombre de réactions endergoniques; ce sont non seulement des réactions anaboliques [...], mais encore certaines réactions de transports, de transmissions, des travaux mécaniques, fonctionnement du système nerveux, réactions cataboliques, en particulier lorsque les substrats doivent être activés avant de pouvoir être dégradés. [...] L'énergie nécessaire est fournie par les réactions exergoniques grâce au couplage énergétique. Ce couplage énergétique est une des grandes caractéristiques des êtres vivants. D'une part, il implique que la réaction exergonique qui fournit l'énergie ait un [delta]G' négatif plus élevé en valeur absolue que le [delta]G' positif de la réaction endergonique qui lui est couplée. D'autre part, les deux réactions couplées doivent avoir un intermédiaire commun.  2, record 1, French, - r%C3%A9action%20coupl%C3%A9e

Record 1,  Textual support,  Spanish