Diffusion and Transport of Molecules In Living Cells

Diffusion, derived from the Latin word diffundere meaning to spread out, is a mass transport phenomenon in both fluids (without requiring bulk fluid motion) and solids. Both macroscopic or phenomenological and microscopic or atomistic and molecular approaches are employed to introduce the concept of diffusion. According to the former approach, the diffusion transport goes from regions of high concentration to regions of low concentration, whereas according to the latter diffusion is a result of the random walk of the particles. In molecular diffusion, moving molecules are self-propelled by thermal energy. In this chapter we discuss the historical developments, diffusion in cells and the current status of research , basic mathematical models of diffusion, and osmosis and its importance for living systems.