What does the concentration gradient refer to in a solution?

The concentration gradient in a solution specifically refers to the graduated difference in solute concentration between two areas, such as across a membrane or within a given volume of solvent. This concept is fundamental in understanding processes like diffusion, where molecules move from an area of higher concentration to an area of lower concentration in an effort to reach equilibrium.

In biological systems, concentration gradients are crucial for processes such as nutrient absorption, gas exchange, and cellular signaling. Cells often rely on these gradients to transport substances necessary for their functions, demonstrating how vital the concept is in various physiological contexts. The idea of a concentration gradient is pivotal in explaining how diffusion occurs and why certain substances can move in and out of cells effectively.