What process describes the movement of molecules from an area of higher concentration to an area of lower concentration?

The process that describes the movement of molecules from an area of higher concentration to an area of lower concentration is diffusion. This fundamental concept in biology is crucial for understanding how substances move within cells and across membranes. During diffusion, molecules spontaneously spread out to evenly fill the available space, moving down their concentration gradient without the need for external energy.

This intrinsic tendency for molecules to move from areas of high concentration to areas of low concentration is vital for numerous biological processes, such as the exchange of oxygen and carbon dioxide in the lungs, the absorption of nutrients in the intestines, and the removal of waste products from cells.

In contrast, other processes like osmosis, active transport, and filtration either involve specific mechanisms or require energy. Osmosis specifically pertains to the movement of water molecules through a selectively permeable membrane, while active transport requires energy to move substances against their concentration gradient. Filtration involves the movement of liquid through a filter, typically driven by pressure differences, rather than concentration gradients. Understanding diffusion lays the groundwork for exploring these other critical processes in physiology and cell biology.