This book describes half a century of progress in two mainstream areas of biological research: membrane transport, initially a focus of physiologists, and oxidative phosphorylation, initially a focus of biochemists. Robinson shows how the development of new explanatory models had unexpectedly merged these inquiries into a new field, bioenergetics. In the late 1930s, explanations for the asymmetric distribution of ions between cells and their environments invoked absolute impermeabilities of the cell's surrounding membranes. But new experiments contradicted that idea and demonstrated that forming the transmembrane distributions required metabolic energy, implying the participation of active transport "pumps." Subsequent studies identified, isolated, and characterized these pumps as enzymes coupling ionic transport to the consumption of adenosine triphosphate (ATP), an "energy-rich" molecule serving as a cellular energy store. In the late 1930s oxidative phosphylation, the process of coupling ATP synthesis to oxidative metabolism, was identified. The explanatory model emerging in the next decades, however, did not follow the enzymatic precedents of known metabolic phosphorylations but rather embodied the principle that metabolic oxidations drive active transport pumps to create transmembrane distribution of ions, with these ionic asymmetries then driving ATP synthesis. It was discovered that ATP consumption can form ionic asymmetries; ionic asymmetries can drive ATP formation; and ionic asymmetries-like ATP-can also power other cellular functions.

Klappentext

This book describes a half century of research on cellular membrane transport and on metabolic energy capture and utilization. During this time-which begins in the late 1930s-the effort and imagination of various scientists overthrew reigning formulations, created novel explanatory models, and unified previously distinct experimental fields. My primary goal is to display the course of that research, showing how new experiments defined novel entities and processes, and how an encompassing field, bioenergetics, then emerged. A secondary goal is to present examples of mainstream biological research that illustrate how experimental results-seen as refutations, confirmations, and elabora­ tions-can sway opinion toward a solid consensus. This interpretation differs from the currently fashionable view of some commentators that stresses instead the central roles of power, prestige, gender, class, and ethnicity. In any case, the scien­ tific practices exhibited here deserve proper philosophical scrutiny. Although con­ straints of space have squeezed any analysis from this draft, brief mention of salient issues does appear in relevant chapters and in the final conclusions. (Oddly, histori­ ans and philosophers seem reluctant to deal with this science. Those who do consider biological topics tend to focus on the theory of evolution, even though the bulk of biological research in this century, in terms of papers published and technology influenced, has dealt not with evolution per se but with what may be termed physiology and biochemistry. And these endeavors, which are the aims, efforts, and accomplishments of the vast majority of biologists, have been largely ignored.

Inhalt

Introduction.- Views in the 1930s.- Accounting for Asymmetric Distributions of Na+ and K+ in Muscle.- Accounting for Asymmetric Distributions of Na+ and K+ in Red Blood Cells.- Ion Gradients and Movements in Excitable Tissues.- Epithelial Transport by Frog Skin.- Contemporary Events: 1939-1952.- Characterizing the Na+/K+ Pump.- Identifying the Na+/K+-ATPase.- Contemporary Events: 1953-1965.-Characterizing the Na+/K+-ATPase.-Structure and Relatives of the Na+/K+-ATPase.- Alternatives.- Using the Transmembrane Cation Gradients: Transporters and Channels.- Contemporary Events: 1966-1985.- Oxidative Phosphorylation: Chemical-Coupling Hypothesis.- Oxidative Phosphorylation: Chemiosmotic Coupling Hypothesis.- Oxidative Phosphorylation: F1, F0F1, and ATP Synthase.- Conclusions.