Electrochemical Models for Biological Energy Conversion

Many particles pass through the membrane of a cell with the electrochemical energy gradient, but some against it. Adenosin triphosphate (ATP) is thought to provide the energy for this latter occurrence. An important biochemical reaction is, then, the endothermic formation of ATP by the phosphorylation process. The enzymes which are associated with this are found in the subcellular unit known as the mitochondrion. Electrochemical reactions may function here. 

Mitchell used Nernstian ideas of electrochemistry to support a concept of the functioning of biological membrane which he called chemiosmotic, as descriptive of a reversible potential difference arising across the membrane as a result of osmotic forces. Mitchell does not consider the transfer of protons as in conduction (or electronic conduction associated with it). He assumes that a carrier system transports H from 

Two substantial reviews and discussions of biological and cellular processes in terms of electrodics have been published by KelF and Berry. Berry emphasized that an exergonic oxidation reaction can initiate an electrochemical process without direct chemical coupling, and, thus, the biological cell is a complex electrochemical device, rather than a chemically powered heat engine, and metabolic reactions are electrochemical processes, giving rise to proton currents. 

FIGURE 6. Stoichiometry of chemiosmotic coupling. The circulation of one proton is caused by the utilization of a certain number (O/ - H ) of oxygen atoms, and causes the synthesis of a certain number (P/- ) of ATP molecules. The P/O quotient is the product (P/- H+)x(-H+/0).  

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