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Natural Organic Photosynthetic Solar Energy Transduction
Published in Sun Sam-Shajing, Sariciftci Niyazi Serdar, Organic Photovoltaics, 2017
The electrons extracted from water are donated to Photosystem II, and after a second light-driven electron transfer step by Photosystem I [8], eventually reduce an intermediate electron acceptor, the oxidized form of nicotinamide adenine dinucleotide phosphate (NADP+). Protons are also transported across the membrane and into the thylakoid lumen during the process of the noncyclic electron transfer, creating a pH difference, which contributes to the proton motive force. The energy in this proton motive force is used to make ATP. The NADPH and ATP that are formed in the light-driven steps of photosynthesis are used to fix CO2 to form sugars and other organic products that give energy for metablolism and growth of the organism. Excess stored energy is available to us in the form of food, fiber, and biomass.
Systems Biology Approach and Modeling for the Design of Microbial Cell Factories
Published in Kazuyuki Shimizu, Metabolic Regulation and Metabolic Engineering for Biofuel and Biochemical Production, 2017
Oxygen serves as a final electron acceptor of the electron transport chain (ETC) (Ingredew and Poole 1984, Bettenbrock et al. 2014), where the function of ETC is to successively transport electrons from donors to acceptors, while translocating protons from cytoplasm through inner (cytosolic) membrane into periplasm. The resulting proton motive force (ΜMF) caused by the proton gradient across the membrane between cytosol and periplasm can be used to generate ATP by ATPase. In relation to ETC, dehydrogenases oxidize cytoplasmic electron donors such as NADH and FADH2 by reducing membrane-associated quinones to quinoles, where the related enzymes are NADH dehydrogenase I (Nuo) (Hayashi et al. 1989) and II (Ndh) (Young and Wallace 1976), succinate dehydrogenate (SDH), and fumarate reductase (Frd) (Hirsch et al. 1963, Guest 1981), where NADH-I encoded by nuoABCDE operon translocates proton contributing ATP generation, while NDH-II encoded by ndh does not translocate proton, and not contributing to the generation of ΜMF (H+/O = 0).
Diazinon impairs bioenergetics and induces membrane permeability transition on mitochondria isolated from rat liver
Published in Journal of Toxicology and Environmental Health, Part A, 2020
Camila Araújo Miranda, Anilda Rufino de Jesus Santos Guimarães, Paulo Francisco Veiga Bizerra, Fábio Erminio Mingatto
Mitochondria are responsible for synthesis of almost all of the ATP that is required for maintaining cellular structure and function. The proton motive force, whose major impetus is the membrane potential (ΔΨ), which is generated by electron transport along the respiratory chain in the inner mitochondrial membrane, drives ATP synthesis via oxidative phosphorylation (Mitchell 1961). Experimental evidence indicates that mitochondria represent a critical and preferred target for the action of drugs and toxins (Meyer et al. 2013). The toxic effects on mitochondria might occur through direct and indirect actions, leading to mitochondrial dysfunction including (1) changes in electron transport and oxidative phosphorylation, (2) increase in inner membrane permeability, (3) deregulation of calcium homeostasis, and (4) shifts in the redox state, as well as a series of other events that deplete ATP (Bizerra et al. 2018; Castanha-Zanoli et al. 2012; Dykens et al. 2008; Li et al. 2012; Nadanaciva et al. 2007; Oliveira et al. 2020).
Green hydrogen production by Rhodobacter sphaeroides
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Dahbia Akroum-Amrouche, Hamza Akroum, Hakim Lounici
Electron transfer pushes the protons into cytoplasmic membrane cavities that communicate with periplasms, thereby establishing a proton motive force. ATP synthetase (or ATP ase) reverse proton translocation to the cytoplasm and catalyzes the synthesis of ATP from ADP and phosphate.