CORRELATION BETWEEN THE MOLECULAR CONFIGURATION OF ORGANIC COMPOUNDS AND THEIR ACTIVE TRANSFER IN LIVING CELLS

Abstract

Active transfer resembles permeation in that a substance, after having entered a living system through its surface layer, reappears somewhere beyond this layer, either inside the protoplasm or beyond and outside the living system. It differs from permeation in that, first, it is associated with the expenditure of energy which derives from metabolic reactions inside the living system; second, this energy allows passage to those substances which otherwise would not be admitted to the cell body; and, third, the substance in question frequently reappears at a higher concentration level, in other words, it is transported against a concentration gradient. Certainly, arrival at a higher concentration level is not necessarily associated with the expenditure of energy. For example, in a system of electrolytes, unequally distributed, and about to reach a Donnan equilibrium, the cations may move up-hill, when, simultaneously, the anions go down-hill. However, when in a living system both cations