What is a diffusion gradient?

A diffusion gradient refers to a difference in the concentration of molecules between two regions. This gradient serves as the driving force for diffusion, which is the process where molecules move from an area of higher concentration to an area of lower concentration until equilibrium is reached. When molecules move through a medium, such as air or water, they tend to spread out evenly, and this movement occurs along the gradient created by the uneven distribution of the molecules.

In the context of biological systems, diffusion gradients play a crucial role in processes like gas exchange in the lungs, nutrient absorption in the intestines, and the movement of ions across cell membranes. The energy for this movement does not come from an external source but rather from the inherent kinetic energy of the molecules themselves, which leads to their random motion.

This understanding of a diffusion gradient highlights how biological systems utilize concentration differences to facilitate essential functions, making it a fundamental concept in biology, particularly in areas relating to cellular processes and environmental interactions.