Activation

Activation in (bio-)chemical reaction.

Contents

[edit] Chemistry

In protection, in which the resulting state exhibits a decreased propensity to undergo a certain reaction.

The energy of activation[1] specifies 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 is called chemical kinetics.

[edit] Biology

[edit] Biochemistry

In 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 the cofactor is placed on the enzyme, causing it to only stay active while the cofactor stays on. However, when the cofactor is removed, the enzyme stops being active.

[edit] Immunology

In autoimmune diseases.

Activation and deactivation results from a variety of factors, including adhesion molecules, bacterial products and viral products.

[edit] Physics

Similarly, Prompt Gamma Neutron Activation Analysis (PGNAA) is a rapid, nondestructive, instrumental, nuclear technique which is used for trace and major component analysis of various elements.

[edit] Electrophysiology

Activation refers to the opening of ion channels, i.e. the conformational change that allows ions to pass.

[edit] References

  1. ^ The Activation Energy of Chemical Reactions



This article uses material from the Wikipedia article Activation, which is released under the Creative Commons Attribution-Share-Alike License 3.0.

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