where are protons pumped in electron transport chain
across the mitochondrial inner membrane
title: Electron transport chain text: chain electrons move from an electron donor (NADH or QH) to a terminal electron acceptor (O) via a series of redox reactions. These reactions are coupled to the creation of a proton gradient across the mitochondrial inner membrane. There are three proton pumps: "I", "III", and "IV". The resulting transmembrane proton gradient is used to make ATP via ATP synthase. The reactions catalyzed by "Complex I" and "Complex III" work roughly at equilibrium. This means that these reactions are readily reversible, by increasing the concentration of the products relative to the concentration of the reactants (for example, by increasing the title: Electron transport chain text: of protons across a membrane, producing a proton gradient. The proton gradient is used to produce useful work. About 30 work units are produced per electron transport. Electron transport chain An electron transport chain (ETC) is a series of complexes that transfer electrons from electron donors to electron acceptors via redox (both reduction and oxidation occurring simultaneously) reactions, and couples this electron transfer with the transfer of protons (H ions) across a membrane. This creates an electrochemical proton gradient that drives the synthesis of adenosine triphosphate (ATP), a molecule that stores energy chemically in the form of highly strained bonds. title: Electron transport chain text: proton pumps; others are not. Most oxidases and reductases are proton pumps, but some are not. Cytochrome "bc" is a proton pump found in many, but not all, bacteria (it is not found in "E. coli"). As the name implies, bacterial "bc" is similar to mitochondrial "bc" ("Complex III"). Proton pumps are the heart of the electron transport process. They produce the transmembrane electrochemical gradient that enables ATP Synthase to synthesize ATP. Cytochromes are pigments that contain iron. They are found in two very different environments. Some cytochromes are water-soluble carriers that shuttle electrons to and from large, immobile macromolecular title: Electron transport chain text: their cell membrane. In chloroplasts, light drives the conversion of water to oxygen and NADP to NADPH with transfer of H ions across chloroplast membranes. In mitochondria, it is the conversion of oxygen to water, NADH to NAD and succinate to fumarate that are required to generate the proton gradient. Electron transport chains are major sites of premature electron leakage to oxygen, generating superoxide and potentially resulting in increased oxidative stress. The electron transport chain consists of a spatially separated series of redox reactions in which electrons are transferred from a donor molecule to an acceptor molecule. The underlying force title: Electron transport chain text: by Nobel Prize in Chemistry winner Peter D. Mitchell, the electron transport chain and oxidative phosphorylation are coupled by a proton gradient across the inner mitochondrial membrane. The efflux of protons from the mitochondrial matrix creates an electrochemical gradient (proton gradient). This gradient is used by the FF ATP synthase complex to make ATP via oxidative phosphorylation. ATP synthase is sometimes described as "Complex V" of the electron transport chain. The F component of ATP synthase acts as an ion channel that provides for a proton flux back into the mitochondrial matrix. It is composed of a, b and c