TKANSPORT in PLANIS Let us discuss another experiment where a solution of sucrose in water taken in a funnel is separated from pure water in a beaker by a sdectively permeable membrane (Figure 11.4). You can get this kind of a membrane in an egg. Remove the yolk and albumin through a small hole at one end of the egg. and place the shell in dilute solution of hydrochloric acid for a few hours. The egg shell dissolves leaving the membrane intact. Water will move into the funnel. resulting in rise in the level of the solution in the funnel. This will continue till the equilibrium is reached. In case sucrose does diffuse out through the membrane, will this equilibrium be ever reached? External pressure can be applied from the upper part of the funnel such that no water diffuses into the funnel through the membrane. This pressure required to prevent water from diffusing is in fact. the osmotic pressure and this is the function of the solute concentration; more the solute concentration. greater will be the pressure required to prevent water from diffusing in. Numerically osmotic pressure is equivalent to the osmotic potential, but the sign is opposite. Osmotic pressure is the positive pressure applied, while osmotic potential is negative. 11.2.3 Plasmolysis