Ozmózis

Ozmózis, commonly called osmosis in English, is the movement of water molecules through a semi-permeable membrane from a solution with lower solute concentration to one with higher solute concentration. This process tends to equalize solute concentrations on the two sides of the membrane.

The membrane is permeable to water but restricts most solutes, such as salts or proteins. The driving force is osmotic pressure, a colligative property that arises from differences in solute concentration, or more generally water potential.

In biology, osmosis is essential for cellular osmoregulation. Plant cells rely on osmosis for turgor pressure; animal cells maintain volume through fluid balances. In red blood cells, hypotonic solutions cause swelling and potential lysis, while hypertonic solutions cause shrinkage.

Applications include medical treatments such as dialysis, where osmosis helps remove waste, and industrial processes, including water purification and desalination. The related process of reverse osmosis applies external pressure to reverse the direction of water flow.

Measurement and history: Osmolarity and osmolality quantify solute concentration, while osmotic pressure predicts the direction and extent of water movement. The concept was formalized in the 19th century by Wilhelm Pfeffer, who introduced the term osmosis and described osmotic pressure. Ozmózis remains a fundamental concept across biology, chemistry, medicine, and environmental science.