Cell Membrane Transport [antikvár]

PREFACE It is not a particularly rewarding task to engage in writing a book on a subject which is undergoing a rapid and potentially revolutionary development, but, on the other hand, the investigation of transport of substances into and out of cells has reached a stage of maturity or at least of self-realization and this fact alone warrants a closer examination of the subject. No one will doubt at present that the movement—mostly by selective translocation—of substances, ranging from hydrogen ions to deoxyribonucleic acids, across the cell-surrounding barriers represents one of the salient features of a living cell and that, if we are permitted to go so far, the cessation of the selective transport processes might be considered as the equivalent of cell death. Hardly anybody will question the premise that cell and tissue differentiation within the ontogenetic development of an organism is closely associated with properties of the outer cell face. Perhaps no serious scholar will attempt to refute the concept that membranes with characteristic morphology and composition represent the architectural framework for the whole cell. And probably no experienced biologist will raise objections to the belief that many physiological processes, like nervous impulse conduction and other electrical phenomena of cells and tissues or their volume changes, are associated with membrane-regulated shifts of ions and molecules. Still, perhaps because all these observations comprise a border discipline par excellence, textbooks of biochemistry hardly ever mention the problem of biological transport, textbooks of physiology deal at most with the ion and water movement in the kidney, and textbooks of biophysics (the few there are) treat membrane phenomena and ion distribution in cells rather one-sidedly. Bringing together all the pertinent information—an awesome task—is thus imperative at this stage of experimental research. However, collating vii