Diffusion of water inside and outside of a cell, during osmosis the equal amount of solute and solution inside and outside a cell is trying to be maintained. Hypertonic cells shrivel up because there is more solute outside a cell (Plasmolysis). Hypotonic cells take in too much water because there is more solute inside the cell (Cytolysis). Isotonic cells are cells where the inside and outside of the cell are equal and water moves in and out of the cell. Aquaporens: pores that let in water.