This chapter begins by considering a kind of transports through the biological membranes, that is to say the crossing across them under active transport and more precisely by considering what is named osmotic work. It gives some examples of such transports and conditions under which they are operating. The chapter also considers the case where an active transport results in a bioelectric phenomena such as an action potential. It briefly considers the notion of transcellular active transport. Contrary to the homocellular transport mechanism, transcellular active transport takes place across a whole cell or a whole layer of cells. In this process, the “pumps” work at different rates on the opposite sides of cells. “Pumps” may be of different kinds. When the nerve cell is excited by reception of an impulse from the next cell, or by electrical stimulation, it is found that a “wave” travels along the axon at a high rate.