All of the following are true regarding Donnan effect except
Correct Answer: Non diffusible ion on one side of membrane affects the distribution of other diffusible ions
Description: "When an ion on one side of a membrane cannot diffuse through the membrane, the distribution of other ions to which the membrane is permeable is affected in a predictable way. The Donnan effect on the distribution of ions has three effects in the body. First, because of charged proteins (Prot-) in cells, there are more osmotically active paicles in cells than in interstitial fluid, and because animal cells have flexible walls, osmosis would make them swell and eventually rupture if it were not for Na, K ATPase pumping ions back out of cells. Thus, normal cell volume and pressure depend on Na, K ATPase. Second, because at equilibrium the distribution of permeant ions across the membrane (m in the example used here) is asymmetric, an electrical difference exists across the membrane whose magnitude can be determined by the Nernst equation. Third, because there are more proteins in plasma than in interstitial fluid, there is a Donnan effect on ion movement across the capillary wall." "The plasma proteins do more than just act as osmotic agents. Because these proteins also carry negative charges, the Donnan effect causes an increase in both the concentrations of cations and the colloid osmotic pressure in the capillary lumen."
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