Active and Coupled Uphill Transport

Abstract

In chapters 3 and 4, transport mechanisms that permit substances to pass across membranes in order to reach states of chemical or electrochemical equilibrium were treated. In other words, the transfer of substances, whether uncharged or ionic in character, by such systems need not be directly coupled to a source of metabolic energy, all the movement being provided for by the simple physicochemical forces (concentration, electrical potential gradients) operating in the system.