Is osmosis considered a passive or active process?

Osmosis is considered a passive process because it does not require the expenditure of energy to occur. Instead, it relies on the natural movement of water molecules from an area of lower solute concentration to an area of higher solute concentration, aiming to achieve equilibrium on both sides of a semipermeable membrane. This movement occurs because of the concentration gradient, where molecules move spontaneously from areas of higher concentration to areas of lower concentration.

In contrast to active transport processes, which utilize energy (often in the form of ATP) to move molecules against their concentration gradient, osmosis is driven purely by the intrinsic kinetic energy of the molecules involved. This fundamental principle establishes osmosis as a key concept in cellular function, particularly in maintaining cell turgor and homeostasis.

Understanding osmosis as a passive process highlights its role in various physiological functions, such as nutrient absorption and waste elimination in cells.