UTF-8Gibbs-Donnan EffectExploring the Gibbs-Donnan Effect.
For background see: http://en.wikipedia.org/wiki/Gibbs–Donnan_effect
This simulation represents a cell membrane with protein channels that allow ions to pass through the membrane.
Inside the cell there are 40 negative charges on macromolecules that cannot cross the membrane and leave the cell.
Each macromolecule has two negative charges. Suppose we start the simulation with only 20 positive charges
inside the cell. What do you predict will happen as the simulation proceeds. The simulation is set up with
the dielectric constant = 80 to simulate water solution.
At the start of the simulation, is ∆G >0, <0 or = 0 for the process Ions(outside) --> Ions(inside)?
Predict the distribution of ions once equilibrium is reached and ∆G = 0.
Is the electrical charge balanced? If not, is there
an electric field across the cell membrane? Which way does it point?
Is there a concentration gradient of the Positive ions?
Does the electric field point in the same direction as the concentration gradient of positive ions or in the opposite direction?
Inside of cell: Outside of cell:
16truetrueorg.concord.mw2d.activity.AtomContainerGibbs-Donnan with Macromolecules$0.mml