Donnan Effect?

Question

what is the relation of Donnan effect to osmotic pressure, on capillary and on ph?

what is the significance of the Donnan equilibrium to the biological system ?

what is the color of phenolphthalein, bromphenl ble, and phenol red in acidic and in base media?

Answer 1

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

When a biological cell is in a hypotonic environment (the cell interior contains a lower concentration of water than its exterior), water flows across the cell membrane into the cell, causing it to expand due to osmotic pressure. In plant cells, the cell wall restricts the expansion, resulting in pressure on the cell wall from within called turgor pressure. The osmotic pressure π of a dilute solution can be calculated using the formula

π = iMRT,
where

i is the van 't Hoff factor
M is the molarity
R is the gas constant, where R = 0.08206 L atm/mol K
T is the thermodynamic temperature (formerly called absolute temperature)
Note the similarity of the above formula to the ideal gas law and also that osmotic pressure is not dependent on particle charge.


Donnan equilibrium refers to the distribution of ion species between two ionic solutions separated by a semipermeable membrane or boundary. The boundary layer maintains an unequal distribution of ionic solute concentration by acting as a selective barrier to ionic diffusion. Some species of ions may pass through the barrier while others may not. The solutions may be gels or colloids as well as ionic liquids, and as such the phase boundary between gels or a gel and a liquid can also act as a selective barrier.

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.

Answer 2

The Gibbs-Donnan effect (also known as the Donnan effect, Donnan law, or Gibbs-Donnan equilibrium) is a name for the behavior of charged particles near a semi-permeable membrane to sometimes fail to distribute evenly on either side of the membrane. [1] The usual cause is the presence of a different charged substance that is unable pass through the membrane and is thus creating an uneven electrical charge. [2] The Gibbs-Donnan effect can prevent sick cells' sodium pumps from functioning properly. [3]

It is named after physicists Josiah Willard Gibbs and Frederick G. Donnan.

Answer 3

This Site Might Help You.

RE:
Donnan Effect?
what is the relation of Donnan effect to osmotic pressure, on capillary and on ph?

what is the significance of the Donnan equilibrium to the biological system ?

what is the color of phenolphthalein, bromphenl ble, and phenol red in acidic and in base media?