Activation energy

Definition

noun

The amount of energy (in joules) needed to convert all the molecules in one mole of a reacting substance from a ground state to the transition state intermediate


Supplement

The activation energy is a term coined by the Swedish scientist, Svante Arrhenius in 1889. It means the amount of energy expressed in joules that is required to convert the molecules in one mole of a reactant from a ground state to the transition state. It can also mean the energy that an atomic system must have before an emission or chemical reaction can occur. The activation energy of a reaction may be denoted by Ea.

In relation to biology (such as biochemistry), the activation energy (or energy of activation) pertains to the energy needed to initiate a reaction. For instance, the activation energy required to breakdown glucose into pyruvic acid in respiration is two ATP.

Accordingly, enzymes speed up chemical reactions by reducing the activation energy of a reaction. Moreover, this reduction by an enzyme allows biological reactions to proceed rapidly at relatively low temperatures tolerable by living organisms.1


Also called:

See also:

Reference(s):
1P. J. Russell. (2008). "Biology: The Dynamic Science, Volume 1." Canada (Belmont): Cengage Learning. ISBN 9781111795559.

Retrieved from "http://www.biology-online.org/bodict/index.php?title=Activation_energy&oldid=99893"
First | Previous (Activation analysis) | Next (Activation product) | Last
Please contribute to this project, if you have more information about this term feel free to edit this page.