Reverse Electron Flow
Reverse Electron Flow - Related Videos
10:34
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Cited by 5 •
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Stable radicals that are present in carbon substrates interact with paramagnetic oxygen through a Heisenberg spin exchange. This interaction can be significantly reduced under STP conditions by flowing a diamagnetic gas over the carbon system. This manuscript describes a simple method to characterize the nature of those radicals.
10:10
Reverse Total Shoulder Arthroplasty
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Reverse total shoulder arthroplasty is indicated for the treatment of conditions that cannot be treated with conventional arthroplasty or other procedures. These primarily include degenerative and incapacitating conditions with irreparable rotator cuff and loss of the normal biomechanical coupling of the shoulder.
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Focussed Ion Beam Milling and Scanning Electron Microscopy of Brain Tissue
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This protocol describes how resin embedded brain tissue can be prepared and imaged in the three dimensions in the focussed ion beam, scanning electron microscope.
01:28
Electron Transport Chains
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2019
The final stage of cellular respiration is oxidative phosphorylation that consists of two steps: the electron transport chain and chemiosmosis. The electron transport chain is a set of proteins found in the inner mitochondrial membrane in eukaryotic cells. Its primary function is to establish a proton gradient that can be used during chemiosmosis to produce ATP and generate electron carriers, such as NAD+ and FAD, that are used in glycolysis and the citric acid cycle. The ETC is comprised of...
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Creation of Reversible Cholestatic Rat Model
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2011
Cholestasis is a clinical condition commonly encountered by both surgeons and gastroenterologists. Creation of a reversible cholestatic rat model can be challenging in view of the smaller size and unique hepatopancreatobiliary anatomy in rats. This video article demonstrates the creation of a reversible cholestatic model.
FAQs
The proton motive force serves as the energy input that makes uphill electron transfer possible. Within the respiratory chain, an electrochemical gradient drives components in reverse, allowing electrons from reduced environmental donors to reach NAD(P)+. This produces NAD(P)H, which supplies reducing power for carbon fixation and synthesis of cellular building blocks.
Some reduced inorganic or environmental electron donors cannot reduce NAD(P)+ directly. The cell therefore uses energy from a proton motive force or another electrochemical gradient to move those electrons through respiratory-chain components toward NAD(P)+. This extra energetic step provides NAD(P)H when direct electron transfer is not thermodynamically available.
Ordinary respiratory electron transfer follows a favorable thermodynamic direction, whereas reverse electron flow moves electrons against that direction. The reversal requires an electrochemical energy source, such as a proton motive force, to power respiratory-chain components. Its importance lies in converting environmental donor electrons into the reducing power required for biosynthetic metabolism.
The process depends on three linked features: a reduced environmental electron donor, respiratory-chain components capable of operating in reverse, and an electrochemical gradient that provides the required energy. The identity of the donor determines the starting point for electrons, while the available gradient determines whether they can reach NAD(P)+ and generate NAD(P)H.
The resulting NAD(P)H supports reductive biosynthetic reactions, especially carbon fixation and the production of cellular building blocks. This connection allows chemolithotrophic microorganisms to use reduced environmental compounds as energy sources while still obtaining the reducing power needed to construct biomass. Reverse electron flow therefore links respiratory energy conversion with cellular growth.
It explains how bacteria and archaea can grow using inorganic compounds even when their initial electron donors do not directly reduce NAD(P)+. Examining this process reveals how energy conservation, electron transfer, carbon fixation, and biosynthesis are connected. It also helps explain how microorganisms adapt their metabolism to diverse environmental conditions.