Membrane Biophysics

Membranes are essential for cell functioning because various components need to be compartmentalized. Biological membranes are selectively permeable as well as providing structure to allow for separation. The chapter introduces the application of physical sciences to the study of membrane function, with consequent ability to quantify cellular processes, in particular, the phenomenon of transmembrane electrical potentials. This arises out of the way physical, chemical, and electrical phenomena interact, giving a quantity known as electrochemical potential. The diffusion of some substances follows electrochemical gradients, but some substances flow “uphill” because of the supply of cellular metabolic energy. This maintains the viability of cells and is an important distinction between living and non-living systems. Nevertheless, the approach outlined in this chapter also has applications in general membrane systems, including filtration, reverse osmosis, fuel cell technology, and battery storage. As well as the movement of solutes, the movement of solvent, water in the case of biological cells, is of fundamental importance, and this too is covered in this chapter.