Osmosis is a specific type of passive transport that refers to the movement of water molecules across a selectively permeable membrane. It occurs from an area of lower solute concentration (where there is a higher concentration of water) to an area of higher solute concentration (where there is a lower concentration of water). This process does not require energy, as it relies on the natural kinetic energy of water molecules and the concentration gradient.
In biological systems, osmosis is crucial for maintaining cellular homeostasis, regulating the internal environment of cells, and ensuring that essential processes like nutrient absorption and waste removal occur efficiently. The selective permeability of cell membranes allows them to control the movement of water and solutes, thus impacting cellular function and overall health.