How do dissolved solutes contribute to the water potential of the cell?

Answer 1

Water potential is
ψ=ψs+ψp where ψs is the contribution of the solutes (osmotic pressure) and ψp the pressure on that side of the membrane.

ψs is always negative, so dissolving solutes lowers the water potential. When there are no cell walls the pressure on both sides of the membrane is the same and thus water potential is equal to ψs.

For plant or bacterial cells which have walls internal pressure can build up so you have to take it into account if you want to see whether water will enter the cells.

Answer 2

these dissolved solutes will change the osmotic pressure in the body and thus lowers the water potential of the cell. in plants if this happens the water in the cell will leave the cell via osmosis to maintain the necessary osmotic pressure in the blood plama in mammals. thus in mammals, the cells will die of dehydration if this condition persists.--> hardly seen as the body has homeostatic ability

In plants however the cells wil not die but it will be plasmolysed bcos of the presence of the cellulose cell walls that will exert a certain pressure until fully plasmolysed. in normal suitations water potential= solute potential + pressure exerted by cell walls(only in plants). when fully plasmolysed, pressure by cell walls is zero and thus water potential=solute potential.

Answer 3

http://en.wikipedia.org/wiki/Osmosis