Redox gradients

Virtually all energy released from the oxidation of carbohydrate, fat, and protein is made available in mitochondria as reducing equivalents (—H or e ). These are funneled into the respiratory chain, where they are passed down a redox gradient of carriers to their final reaction with oxygen to form water. 

The redox carriers are grouped into respiratory chain complexes in the inner mitochondrial membrane. These use the energy released in the redox gradient to pump protons to the outside of the membrane, creating an electrochemical potential across the membrane. 

Most notably, subtle positive spontaneous potential (SP) anomalies can be noted in association with strong, negative-inward, redox gradients (Hamilton Hattori 2008). The goal of our work is to understand the role of micro-organisms in the oxidation process and in the generation of electrical fields. 

Clay samples were collected at areas of high-redox gradient at the edge of the Thorn-north ring and the Bean ring, which are H2S sourced and methane sourced, respectively. These samples were preserved under anoxic conditions and... 

Redox gradients as strong as those observed at the ring edges are potential sources of energy for autotrophic bacteria. Evidence for microbial involvement includes H2S consumption, S042 ... 

Within the depth-dependent redox gradient, concentration peaks of solid Fe(lll) and of dissolved Fe(II) develop, the peak of Fe(III) overlying the peak of Fe(II) ... 

Dipole development around a conductor immersed in an electrolyte with uneven oxidative properties is scale independent. Even tiny conductive or semi-conductive mineral grains in overburden will develop dipoles if there are redox differences across them. Almost all solids have some semi-conductive properties and therefore the nature of the conductive minerals is of less importance than the existence of a redox gradient. Large redox gradients in overburden contain polarisable minerals. 

Redox gradients in Au systems of the Yilgarn Craton, Western Australia have been mapped across gold lodes and at camp to district scales using C and S isotopes combined with alteration studies. These gradients can be related to the interplay of oxidized and reduced... 

Tracing progressive redox gradients and directions of hydrothermal flow using uranium and lithium isotopes... 

Fig. 8 Bridge type connecting the donor and acceptor moieties, (a) Insulating bridge, (b) Redox gradient bridge, and (c) highly conjugated bridge...

Electron-cation symport has been realized in a double carrier process where the coupled, parallel transport of electrons and metal cations was mediated simultaneously by an electron carrier and by a selective cation carrier [6.47]. The transport of electrons by a nickel complex in a redox gradient was the electron pump for driving the selective transport of K+ ions by a macrocyclic polyether (Fig. 12). The pro-... 

Proton transfer is a particularly important transport process. Beyond acid-base reactions, proton transfer may be coupled to electron transfer in redox reactions and to excited-state chemistry. It is of enormous significance in biochemical processes where it is an essential step in hydrolytic enzyme processes and redox reactions spanning respiration, and photosynthesis where proton motion is responsible for sustaining redox gradients. In relatively recent times, proton transfer in the excited state has undergone significant study, primarily fueled by advances in ultrafast spectroscopy. 

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