Consider a simple spherical model cell that consists of cytoplasm and a plasma membrane.
The cell's initial volume is 2 nL and contains 0.2 M protein. The cell is placed in a large volume of 0.05 M CaCl2. Neither Ca++ nor Cl- can cross the plasma membrane and enter the cell. Are the 0.05 M CaCl2 solutions hypotonic, isotonic or hypertonic relative to the osmolarity inside the cell? Describe what happens to the mathematically cell as it achieves equilibrium in this new environment. What will be the final osmolarity of the cell? What will be its final volume?