Water entering a cell is stored in the large, central vacuole (chapter 1), which expands and presses the cytoplasm against the rigid cell wall. When a cell becomes turgid (fully inflated), the rate of water uptake is slowed but does not come to a complete stop. Water continues to diffuse into the cell and simply displaces a comparable volume, while the cell wall, counteracting internal turgor pressures, squeezes water out. Turgid cells are thus equipped with a safety valve that keeps them from inflating to the bursting point.
