Three situations for water potential are covered showing the effect on cell membranes. Water moves to lower water potential regions. The more solute particles, the lower the water potential. Water moves from hypotonic areas to hypertonic areas unless the is a pressure potential. In cytolysis, cells burst as water rushes into the hypertonic area. For plasmolysis, cells shrink as water leaves the cell tomgo intoma hyprtonic solution on the outside.