How is osmosis defined?

Osmosis is defined as the diffusion of water across a selectively permeable membrane. This process occurs when there is a difference in water concentration on either side of the membrane, allowing water to move from an area of higher water concentration (or lower solute concentration) to an area of lower water concentration (or higher solute concentration). This movement continues until dynamic equilibrium is reached, where water molecules continue to move across the membrane, but at an equal rate in both directions.

The selectively permeable nature of the membrane is critical for osmosis because it permits water molecules to pass while restricting the movement of solute molecules. This property plays an essential role in maintaining cellular homeostasis, influencing cell shape, volume, and overall function. Understanding osmosis is fundamental in various biological processes, such as nutrient absorption in cells and the regulation of fluids in organisms.