Donnan equilibrium (which can also be referred to as the Gibbs-Donnan equilibrium) describes the equilibrium that exists between two solutions that are. Looking for online definition of Gibbs-Donnan equilibrium in the Medical Dictionary? Gibbs-Donnan equilibrium explanation free. What is Gibbs-Donnan. According to Gibbs-Donnan equilibrium when two ionized solutions are seprated by a semipermeable membrane at equilibrium- 1. Each solution shall be.

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What does this do to cells? In bacteriafor example, the passage of potassium across the outer membrane of Gram-negative bacteria occurs as a result of an established Donnan equilibrium between the external environment and the periplasm of the bacterium.

We have preserved much of the material of the former hard copy editions, making changes to improve understanding of the concepts in addition to including some of the recent discoveries in physical chemistry. Home Science Encyclopedias almanacs transcripts and maps Donnan Equilibrium.

The negative charge in the cell and ions outside the cell creates a thermodynamic potential; if damage occurs to the brain and cells lose their membrane integrity, ions will rush into the cell to balance chemical and electrical gradients that were previously established.

Donnan effect on chloride ion distribution as a determinant of body gibvs composition that allows action potentials to spread via fast sodium channels. This means that there are more equilinrium inside the cell than outside.

Views Read Edit View history. Donnan equilibrium Donnan equilibrium which can also be referred to as the Gibbs-Donnan equilibrium describes the equilibrium that exists between two solutions that are separated by a membrane.


Cell membranes are selectively permeable, which means that they allow some molecules to pass through while keeping others out. Physical Chemistry Ebook does not work on Windows 8: The Gibbs—Donnan effect also known as the Donnan’s effectDonnan lawDonnan equilibriumor Gibbs—Donnan equilibrium is a name for the behaviour of charged particles near a semi-permeable membrane that sometimes fail to distribute evenly across the two sides of the membrane.

The Donnan Equilibrium Phenomenon in Living Cell Functions

Your email address will not be published. Diffusion occurs when substances move from areas of high concentration to low concentration down a concentration gradient. This post presents the significance of this phenomenon in every day molecular processes.

The inward movement of sodium corrects the imbalance. I love the wonderful world of Chemistry and its practicality. I n vivoion balance does not equilibriate donnna the proportions that would be predicted by the Gibbs-Donnan model, because the cell cannot tolerate the attendant large influx of water.

A equilibdium to physical-chemical physiology]. The earlier Donnan effect Donnan Equilibrium 1 with respect to impermeable anionic colloids balances the latter Donnan effect Donnan Equilibrium 2 of impermeable extracellular sodium.

When tissue cells are in a protein-containing fluid, the Donnan effect of the cytoplasmic proteins is equal and opposite to the Donnan effect of the extracellular proteins.

The Donnan Phenomenon in Living Cell Functions

Because small cations are attracted, but are not bound to the proteins, small anions will cross capillary walls away from the anionic proteins more readily than small cations. Some ionic species can pass through the barrier while others cannot.


Retrieved December 24, from Encyclopedia. Since potassium is freely permeable, it will tend to diffuse out again.

The chemical aspect of the topic is captured in Chapter 7 of the Physical Chemistry book. The two solutions vary in osmotic pressurewith one solution having more of a certain type species or types of ion that does the other solution. The membrane voltage will become zero, but the chemical gradient will still exist. Posted in Chapter 7Study Tips.

The solutions may be gels or colloids as well as solutions of electrolytesand as such the phase boundary between gels, or a gel and a liquid, can also act as a selective barrier. Welcome to Physical Chemistry. When the charged groups are positive acidicthen they will repel protons so that the pH will be higher than the surrounding buffer.

The Donnan effect may explain why some red blood cells do not have active sodium pumps; dojnan effect relieves the osmotic pressure of plasma proteins, which is why sodium pumping is less important for maintaining the cell volume. Donnan equilibrium which can also be referred to as the Gibbs-Donnan equilibrium describes the equilibrium that exists between two solutions that are separated by a membrane.

If this process continues, the cells will inevitably rupture.