The combined use of diamagnetic and paramagnetic chemical shift changes makes it possible to obtain detailed information about the structure of a transient complex of redox proteins. The structure suggests that the electrostatic interactions 'guide' the partners into a position that is optimal for electron transfer, and which may be stabilised by short-range interactions.

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Recent advances in fuel cell (FC) and microbial fuel cell (MFC) research have demonstrated these electrochemical technologies as effective methods for generating electrical power from chemical fuels and organic compounds. This led to the development of MFC-inspired photovoltaic (BPV) devices that produce electrical power by harvesting solar energy through biological activities of photosynthetic organisms. We describe the fabrication of a BPV device with multiple microchannels. This allows a direct comparison between sub-cellular photosynthetic organelles and whole cells, and quantitative analysis of the parameters affecting power output. Electron transfer within the photosynthetic materials was studied using the metabolic inhibitors DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) and methyl viologen (1,1 0 -dimethyl-4,4 0 -bipyridinium dichloride). These experiments suggest that the electrons that cause an increase in power upon illumination leave the photosynthetic electron transfer chain from the reducing end of photosystem I. Several key factors limiting performance efficiency, including density of the photosynthetic catalyst, electron carrier concentration, and light intensity were investigated.

Pathways of electron transport have been studied in mitochondria isolated from hypocotyls of etiolated mung bean seedlings and skunk cabbage spadices that show cyanide-resistant respiratory activity. The (27) confirmed the high oxygen affinity in tissues of the Arum maculatum spadix.Hypothesis 3. The simplest explanation of cyanide-insensitive respiration is that there is incomplete inhibition of cytochrome c oxidase. Such a situation could arise if the mitochondria contained a large excess of cytochrome oxidase relative to a rate-limiting step in the respiratory chain. The excess oxidase hypothesis has been discussed in relation to plants