Practice Problems – Osmosis and Water potential
Use this key to answer all the problems below. If you choose B or C, rewrite the statement
so that it is complete and true.
T = TRUE F = FALSE N = NOT ENOUGH INFORMATION
PROBLEM ONE: The initial molar concentration of the cytoplasm inside a cell is 2M and the
cell is placed in a solution with a concentration of 2.5M.
1. It is possible that this cell is already in equilibrium with its surroundings.
F The cell must lose water to reach equilibrium. There is no way pressure can build up
to bring the cell to equilibrium.
2. Initially, solute concentration is greater outside the cell than inside.
T
3. Water will enter the cell because solute potential is lower inside the cell than outside.
FWater will leave the cell because solute potential is higher inside the cell than outside.
4. The cell will become flaccid because the pressure potential is greater outside the cell
than inside.
F The cell will become more flaccid because the solute potential is greater inside the cell
than outside.
5. The cell is already in equilibrium with its surroundings because of the combination of
pressure potential and solute potential inside and outside the cell.
F The cell is not in equilibrium because there is no pressure potential inside the cell and
none will build up when water leaves the cell.
6. Initially, the cytoplasm is hypertonic to the surrounding solution.
F ...... cell is hypotonic to the surrounding solution.
7. Initially, the numerical value of the solute potential is more negative inside the cell than outside.
F ...... more negative outside the cell than inside.
8. Net diffusion of water will be from inside the cell to outside the cell.
T
9. At equilibrium, the molarity of the cytoplasm will have increased.
T
10. At equilibrium, the pressure potential inside the cell will have increased.
F ..... pressure potential inside the cell will remain zero.
PROBLEM TWO: The initial molar concentration of the cytoplasm inside a cell is 1.3 M and
the surrounding solution is .3M.
1. The cell could already be in equilibrium with the surrounding solution.
T
