Gibbs-Donnan effect

Gibbs-Donnan effect

The Gibbs-Donnan effect (also known as the Donnan effect, Donnan law, Donnan equilibrium, or Gibbs-Donnan equilibrium) is a name for the behavior of charged particles near a semi-permeable membrane to sometimes fail to distribute evenly across the two sides of the membrane. [http://www.cartage.org.lb/en/themes/Reference/dictionary/Biologie/G/13.html, retrieved 28 August 2006] The usual cause is the presence of a different charged substance that is unable to pass through the membrane and thus creates an uneven electrical charge. [ [http://www.people.vcu.edu/~mikuleck/courses/gdeq/sld001.htm The Gibbs-Donnan Equilibrium...] , D.C. Mikulecky, retrieved 28 August 2006] For example, the large anionic proteins in blood plasma are not permeable to capillary walls. Because small cations are attracted-to but not bound-to the proteins, small anions will cross capillary walls more readily than small cations.

The Gibbs-Donnan effect can prevent sick cells' sodium pumps from functioning properly. [ [http://www.everything2.com/index.pl?node_id=1207400 Gibbs-Donnan effect] , Everything2.com, retrieved 28 August 2006] Some ionic species can pass through the barrier while others cannot. The solutions may be gels or colloids as well as solutions of electrolytes, and as such the phase boundary between gels, or a gel and a liquid, can also act as a selective barrier. The electric potential arising between two such solutions is called the Donnan potential.

The effect is named after the physicist Josiah Willard Gibbs and the chemist Frederick G. Donnan.

The Donnan equilibrium is prominent in the triphasic model for articular cartilage proposed by Mow and Ratcliffe, as well as in electrochemical fuel cells and dialysis.

The Donnan effect is extra osmotic pressure attributable to cations (Na+ and K+) attached to dissolved plasma proteins.

ee also

*Chemical equilibrium
*Nernst equation
*Double Layer (biospecific)
*Osmotic pressure
*Equilibrium

References

*IUPAC Compendium of Chemical Terminology 2nd Edition (1997)
*Van C. Mow and Anthony Ratcliffe "Basic Orthopedic Biomechanics", 2nd Ed. Lippincott-Raven Publishers, Philadelphia, 1997


Wikimedia Foundation. 2010.

Игры ⚽ Поможем решить контрольную работу

Look at other dictionaries:

  • Gibbs–Donnan effect — Donnan equilibrium across a cell membrane (schematic) The Gibbs–Donnan effect (also known as the Donnan effect, Donnan law, Donnan equilibrium, or Gibbs–Donnan equilibrium) is a name for the behavior of charged particles near a semi permeable… …   Wikipedia

  • Gibbs-Donnan effect — Donnan equilibrium …   Medical dictionary

  • Gibbs-Donnan equilibrium (effect) — Gibbs Don·nan equilibrium (effect) (gibzґ donґən) [J.W. Gibbs; Frederick George Donnan, English chemist, 1870–1956] Donnan equilibrium …   Medical dictionary

  • Donnan-Gleichgewicht — Schematische Darstellung des Donnan Gleichgewichts über eine Zellmembran Das Donnan Gleichgewicht beschreibt in der Physikalischen Chemie die ungleiche Verteilung von gelösten geladenen Teilchen (Ionen), die sich einstellt, wenn eine… …   Deutsch Wikipedia

  • Donnan equilibrium — Don·nan equilibrium dän ən n the ionic equilibrium reached in a solution of an electrolyte whose ions are diffusible through a semipermeable membrane but are distributed unequally on the two sides of the membrane because of the presence of a… …   Medical dictionary

  • Josiah Willard Gibbs — Infobox Scientist box width = 300px name = J. Willard Gibbs image size = 300px caption = Josiah Willard Gibbs birth date = birth date|1839|2|11|mf=y birth place = New Haven, Connecticut, USA death date = death date and… …   Wikipedia

  • Frederick G. Donnan — Infobox Scientist name = PAGENAME box width = image width =150px caption = PAGENAME birth date = September 6, 1870 birth place = Sri Lanka death date = December 16, 1956 death place = Canterbury, England residence = citizenship = nationality =… …   Wikipedia

  • Scientific phenomena named after people — This is a list of scientific phenomena and concepts named after people (eponymous phenomena). For other lists of eponyms, see eponym. NOTOC A* Abderhalden ninhydrin reaction Emil Abderhalden * Abney effect, Abney s law of additivity William de… …   Wikipedia

  • List of effects — This is a list of names for observable phenonema that contain the word effect, amplified by reference(s) to their respective fields of study. #*3D audio effect (audio effects)A*Accelerator effect (economics) *Accordion effect (physics) (waves)… …   Wikipedia

  • Osmotic pressure — Morse equation redirects here. For the potential energy of a diatomic molecule, see Morse potential. For the functions in differential topology, see Morse theory. Osmotic pressure on red blood cells Osmotic pressure is the pressure which needs to …   Wikipedia

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”