What term describes stiffness in a cell caused by water pressure?

The term that describes stiffness in a cell caused by water pressure is turgor. Turgor pressure is a vital physiological phenomenon that occurs in plant cells. When water enters a plant cell through osmosis, it accumulates in the central vacuole, creating internal pressure against the cell wall. This pressure keeps the cells rigid and maintains the plant's structure, allowing it to stand upright.

Turgor is crucial for various functions in plants, including growth, support, and the transport of nutrients. When turgor pressure is adequate, plants exhibit healthy, firm tissues. Conversely, when turgor pressure decreases due to lack of water, plants can become wilted and less resilient.

Other terms listed do not encapsulate this concept. Osmosis refers to the movement of water across a semipermeable membrane, while hydration pertains to the process of absorbing water. Capacitance typically relates to the ability to store electrical charge, which does not apply to the structural properties of plant cells. Thus, turgor specifically denotes the stiffness and structural integrity provided by internal water pressure within the cell.