TY - CONF. T1 - Tight product binding is the key for efficient electron transfer from D-lactate dehydrogenase 2 to the electron transferring flavoprotein of Saccharomyces cerevisiae. AU - Toplak, Marina. AU - Brunner, Julia. AU - Macheroux, Peter. PY - 2018/7. Y1 - 2018/7. M3 - Poster. T2 - GRC - Enzymes, Coenzymes and Metabolic Pathways. Y2 - 22 July 2018 through 27 July 2018. ER - ...
The ndhB- and psaE- mutants of the cyanobacterium Synechocystis sp. PCC 6803 are partly deficient in PSI-driven cyclic electron transport. We compared photoinhibition in these mutants to the wild type to test the hypothesis that PSI cyclic electron transport protects against photoinhibition. Photoinhibitory treatment greatly accelerated PSI cyclic electron transport in the wild type and also in both the mutants. The psaE- mutant showed rates of PSI cyclic electron transport similar to the wild type under all conditions tested. The ndhB- mutant showed much lower rates of PSI cyclic electron transport than the wild type following brief dark adaptation but exceeded wild type rates after exposure to photoinhibitory light. The wild type and both mutants showed similar rates of photoinhibition damage and photoinhibition repair at PSII. Photoinhibition at PSI was much slower than at PSII and was also similar between the wild type and both mutants, despite the known instability of PSI in the psaE- ...
Beratan, D. N., Hopfield, J. J., & Onuchic, J. N. (1989). Molecular shift register memory based on electron transfer. In Program and Abstracts. New York: Engineering Foundation ...
Electron Transport Chain and Energy Production In cellular biology, the electron transport chain is one of the steps in your cells processes that make energy from the foods you eat.à It is the third step of aerobic cellular respiration. Cellular respiration is the term for how your bodys cells make energy from food consumed. The electron transport chain is where most of the energy cells need to operate is generated. This chain is actually a series of protein complexes and electron carrier molecules within the inner membrane of cell mitochondria, also known as the cells powerhouse. Oxygen is required forà aerobic respirationà as the chain terminates with the donation of electrons to oxygen.à Key Takeaways: Electron Transport Chain The electron transport chain is a series of protein complexes and electron carrier molecules within the inner membrane of mitochondria that generate ATP for energy.Electrons are passed along the chain from protein complex to protein complex until they are donated to ...
The electron transfer properties of proteins are normally measured as molecularly averaged ensembles. Through these and related measurements, proteins are widely regarded as macroscopically insulating materials. Using scanning tunnelling microscopy (STM), we present new measurements of the conductance through single-molecules of the electron transfer protein cytochrome b562 in its native conformation, under pseudo-physiological conditions. This is achieved by thiol (SH) linker pairs at opposite ends of the molecule through protein engineering, resulting in defined covalent contact between a gold surface and a platinum-iridium STM tip. Two different orientations of the linkers were examined: a long-axis configuration (SH-LA) and a short-axis configuration (SH-SA). In each case, the molecular conductance could be gated through electrochemical control of the heme redox state. Reproducible and remarkably high conductance was observed in this relatively complex electron transfer system, with ...
Electron transfer reactions constitute a fundamental chemical process and are of intrinsic importance in biology, chemistry, and the emerging field of nanotechnology. Electron transfer reactions proceed generally in a few limiting regimes: nonadiabatic electron transfer, adiabatic electron transfer and solvent controlled electron transfer. Behavior between some of these regimes was examined by varying the solvents in which the reaction occurs i.e., the different polarization relaxation. In a fast solvent, such as acetonitrile, the electron transfer occurs in the nonadiabatic regime over a broad temperature range; in a slow solvent, such as N-methylacetamide (NMA) and N-methylpropionamide (NMP), the electron transfer reaction occurs in the nonadiabatic regime of high temperature but occurs in the solvent controlled regime as the temperature decreases. The semiclassical model was compared to the electron transfer rate data in the nonadiabatic regime and the Zusman model was compared to the ...
TY - JOUR. T1 - Coexistence of two thermally induced intramolecular electron transfer processes in a series of metal complexes [M(Cat-N-BQ)(Cat-N-SQ)]/ [M(Cat-N-BQ)2] (M = Co, Fe, and Ni) bearing non-innocent catechol-based ligands: A combined experimental and theoretical study. AU - Evangelio, Emi. AU - Bonnet, Marie Laure. AU - Cabañas, Miquel. AU - Nakano, Motohiro. AU - Sutter, Jean Pascal. AU - Dei, Andrea. AU - Robert, Vincent. AU - Ruiz-Molina, Daniel. PY - 2010/6/11. Y1 - 2010/6/11. N2 - The different thermally induced intermolecular electron transfer (IET) processes that can take place in the series of complexes [M(Cat-NBQ)(Cat-N-SQ)]/ [M(Cat-N-BQ)2], for which M = Co (2), Fe (3) and Ni(4), and Cat-N-BQ and Cat-N-SQ denote the mononegative (Cat-N-BQ) or dinegative (Cat-N-SQ 2-) radical forms of the tridentate Schiff-base ligand 3,5-diterf-butyl-1,2-quinone-l-(2-hydroxy-3,5di-tert-butylphenyl)imine, have been studied by variable-temperature UV/ Vis and NMR spectroscopies. Depending on ...
Amino acid radicals are key redox intermediates in several natural enzymes including Cytochrome c peroxidase, DNA photolyase, ribonucletide reductase, cytochrome c oxidase and photosystem II. Electron transfer from amino acids is often coupled to deprotonation and this thesis concerns the coupling of electron transfer from tyrosine and tryptophan to trisbipyridineruthenium(III) with deprotonation in model complexes. Specifically the mechanisms for these proton coupled electron transfer reactions have been studied and the controlling parameters have been identified, the possible mechanisms being stepwise electron transfer followed by deprotonation and deprotonation followed by electron transfer or concerted electron transfer/deprotonation.. Proton coupled electron transfer reactions have been studied using nano-second flash photolysis in water solution and the effect of pH, temperature, reaction driving force, deuteration and nature of the amino acid has been determined. I have shown that the ...
FUNCTION: [Summary is not available for the mouse gene. This summary is for the human ortholog.] The protein encoded by this gene is involved in plasma membrane electron transport pathways. The encoded protein has both a hydroquinone (NADH) oxidase activity and a protein disulfide-thiol interchange activity. The two activities cycle with a periodicity of 24 minutes, with one activity being at its peak when the other is at its lowest. [provided by RefSeq, Dec 2016 ...
TY - JOUR. T1 - Energetic mechanism of cytochrome c-cytochrome c oxidase electron transfer complex formation under turnover conditions revealed by mutational effects and docking simulation. AU - Sato, Wataru. AU - Hitaoka, Seiji. AU - Inoue, Kaoru. AU - Imai, Mizue. AU - Saio, Tomohide. AU - Uchida, Takeshi. AU - Shinzawa-Itoh, Kyoko. AU - Yoshikawa, Shinya. AU - Yoshizawa, Kazunari. AU - Ishimori, Koichiro. PY - 2016/7/15. Y1 - 2016/7/15. N2 - Based on the mutational effects on the steady-state kinetics of the electron transfer reaction and our NMR analysis of the interaction site (Sakamoto, K., Kamiya, M., Imai, M., Shinzawa-Itoh, K., Uchida, T., Kawano, K., Yoshikawa, S., and Ishimori, K. (2011) Proc. Natl. Acad. Sci. U.S.A. 108, 12271-12276), we determined the structure of the electron transfer complex between cytochrome c (Cyt c) and cytochrome c oxidase (CcO) under turnover conditions and energetically characterized the interactions essential for complex formation. The complex structures ...
A continuous supply of energy in the form of ATP is essential to the maintenance of life. In most eukaryotes, it is achieved by oxygen-dependent energy production and the mitochondrial electron transport chain plays a central role in ATP production. In higher eukaryotes, the electron transport chain comprises four integral membrane protein complexes namely, NADH:ubiquinone oxidoreductase (complex I), succinate:ubiquinone oxidoreductase (complex II), ubiquinol:cytochrome c oxidoreductase/ cytochrome bc1 complex (complex III) and cytochrome oxidase (complex IV). The electrons are transferred from NADH and succinate to oxygen through these series of enzymatic complexes of the inner mitochondrial membrane and oxygen is reduced to water. This releases energy and generates a proton gradient across mitochondrial membrane by pumping protons into the intermembrane space. The energy of oxidation of hydrogen is used to phosphorylate ADP into ATP. This ATP generation is catalysed by ATP synthase complex ...
TY - JOUR. T1 - Tunneling time for electron transfer reactions. AU - Nitzan, Abraham. AU - Jortner, Joshua. AU - Wilkie, Joshua. AU - Burin, Alexander L.. AU - Ratner, Mark A.. PY - 2000/6/22. Y1 - 2000/6/22. N2 - The tunneling time for nonadiabatic electron transfer reactions described within the superexchange model is estimated using a Biittiker type internal clock: the electron is taken to possess two internal spin states that are weakly coupled on the bridge. By studying the transition probability between these channels during the tunneling process the traversal time through the bridge can be estimated. Like the Büttiker-Landauer result it is linear in the bridge length, but its dependence on the barrier energy UB approaches the Büttiker-Landauer form only in the limit of strong interstate coupling (broad band). In the normal superexchange (weak coupling) limit it is inversely proportional to the barrier energy.. AB - The tunneling time for nonadiabatic electron transfer reactions ...
TY - JOUR. T1 - Numerical solution of solvent reorganization energy and its application in electron transfer reaction. AU - Bi, Ting Jun. AU - Ming, Mei Jun. AU - Ren, Hai Sheng. AU - Ma, Jian Yi. AU - Li, Xiang Yuan. PY - 2014/8/27. Y1 - 2014/8/27. N2 - According to our recent studies on the nonequilibrium solvation, the solvent reorganization energy λs is found to be the cost of maintaining the residual polarization, which equilibrates with the constraining extra electric field. In this work, a matrix form of λs has been formulated based our new analytical expression of the solvent reorganization energy. By means of the integral equation formulation-polarizable continuum model (IEF-PCM), a new numerical algorithm for λs has been implemented as a subroutine coupled with the Q-Chem package. Then, we have performed a comparison of numerical results with analytical solution obtained by two-sphere model for λs in self-exchange electron transfer (ET) reaction of He-He+ system. The numerical ...
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TY - JOUR. T1 - Intramolecular Electron Transfer from Tryptophan to Guanosyl Radicals in a Linked System as a Model of DNA Repair. AU - Morozova, Olga B.. AU - Fishman, Natalya N.. AU - Yurkovskaya, Alexandra V.. PY - 2017/3/1. Y1 - 2017/3/1. N2 - As a model of chemical DNA repair, intramolecular electron transfer from tryptophan to the radical of the purine base guanosine combined into a conjugate by a flexible linker was studied by time-resolved chemically induced dynamic nuclear polarization (CIDNP). The guanosyl radicals were photochemically generated in the quenching reaction of the triplet excited dye 2,2′-dipyridyl. The CIDNP kinetics was obtained by detection of NMR spectra containing anomalously enhanced signals of diamagnetic products that are formed during a variable period after excitation by a laser pulse. The kinetic data obtained for the protons located on the guanosyl and tryptophanyl moieties of the conjugate were compared to those obtained in photoreactions of the molecules ...
We have studied long-range electron transfer through various lengths of helical peptides from 8 mer (24 Å) up to 80 mer (120 Å) in self-assembled monolayers prepared on a gold surface. Helical peptides carrying a redox-active ferrocene unit and a disulfide group at the respective terminals were synthesized and immobilized on gold via a gold-sulfur linkage to form a well-defined monolayer with vertical helix orientation, and the electron transfer from the ferrocene unit to gold through the helical peptides was studied by electrochemistry. The electron transfer showed a very shallow distance dependence and high activation energies, both of which are characteristic of a hopping mechanism. Detailed theoretical calculations successfully demonstrated that a hopping mechanism with the amide groups as hopping sites is responsible for the long-range electron transfer, which enables ultralong-range electron transfer over 120 Å with the 80 mer helical peptide.
Disponible ahora en Iberlibro.com - ISBN: 9780841216754 - Hard Cover - American Chemical Society - 1990 - Condición del libro: Fine - Not Given - No Jacket - Electron transfer has become a unifying concept for widely disparate groups of researchers. It serves as the bridge between scientists studying electron-transfer processes in solids and those studying the same processes between metal centers in proteins and other biologically significant molecules. This broad and fundamental subject matter is in a state of intellectual ferment, as electron transfer is investigated in such unusual materials as proteins and peptides. Semiconductor and tunneling models, which have often been used to explain conducting properties in solids, also apply to many aspects of long-range biological electron transfer. This book has 470 pages and is illustrated throughout.
In biological redox catalysis, energy transduction, and many aspects of regulation, electron transfer (ET) is linked directly to conformational change, ligand/substrate binding, ion/proton transfer etc., and the ways in which these events occur and how the system as a whole is optimised and harmonised are still not well understood. Studies of biological electron transfer (ET) within multi-cofactor redox enzymes under conditions when the electrode replaces the natural redox partner of the enzyme can contribute to understanding intramolecular ET within the biomolecules followed by ET coupling of the active sites. The obligatory condition for the bioelectrocatalytic event in this case is the existence of a direct communication between the electrode and at least one of the active sites present in the enzyme, which is difficult to attain in some cases. Mimicking the natural partner/environment of protein by the modified electrode is then of particular interest to achieve an efficient ET reaction ...
The electron transfer rates at the steady state are evaluated in terms of the Gaussian wave packet motion on free energy curves in the two- and three-surface models in the presence of inertial effects. The autocorrelation functions of the solvent polarization coordinate are fitted to the results of recent molecular dynamics simulations. It is found that the inertial effects are particularly important for the electron transfer processes in acetonitrile and water. They constitute an impeding factor in the wave packet motion. The neglect of the inertial part of the solvent autocorrelation function gives underestimation of the electron transfer rate coefficient ...
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Individual bacteria use multiple electron transport chains, often simultaneously. Bacteria can use a number of different electron donors, a number of different dehydrogenases, a number of different oxidases and reductases, and a number of different electron acceptors. For example, E. coli (when growing aerobically using glucose as an energy source) uses two different NADH dehydrogenases and two different quinol oxidases, for a total of four different electron transport chains operating simultaneously.. A common feature of all electron transport chains is the presence of a proton pump to create a transmembrane proton gradient. Bacterial electron transport chains may contain as many as three proton pumps, like mitochondria, or they may contain only one or two. They always contain at least one proton pump.. In the present day biosphere, the most common electron donors are organic molecules. Organisms that use organic molecules as an energy source are called organotrophs. Organotrophs (animals, ...
Normal aerobic metabolism (via processes such as photosynthetic and respiratory electron transport chains) in plants yields varied reactive oxygen species (ROS) such as singlet oxygen (1O2), superoxide (O2.¬), hydrogen peroxide (H2O2), and the hydroxyl radical (OH¬). Among the major ROS, H2O2 is an important, relatively stable (under physiological conditions), water-soluble and a longer half-life exhibiting, non-radical w-electron reduction product of oxygen. It has ability to readily cross biological membranes. Literature clearly reflects a double role of H2O2 in normal and (biotic/abiotic)stressed plants. On one hand, H2O2 can be considered essential to plant life because of the involvement of its optimum concentrations in the regulation of specific biological/physiological processes such as photosynthetic functions, cell cycle, growth and development, and plant responses to biotic and abiotic stresses. On the other hand, severe damage to biomolecules such as cellular lipids and proteins and
In this practical text, the author covers the fundamentals of biological electron microscopy - including fixation, instrumentation, and darkroom work - to provide an excellent introduction to the subject for the advanced undergraduate or graduate student.Michael J. Dykstra is the author of Biological Electron Microscopy: Theory, Techniques, and Troubleshooting, published 1992 under ISBN 9780306442773 and ISBN 0306442779. [read more] ...
The electron transport chain (Figure 1) is the last component of aerobic respiration and is the only part of glucose metabolism that uses atmospheric oxygen. Oxygen continuously diffuses into plants; in animals, it enters the body through the respiratory system. Electron transport is a series of redox reactions that resemble a relay race or bucket brigade in that electrons are passed rapidly from one component to the next, to the endpoint of the chain where the electrons reduce molecular oxygen, producing water. There are four complexes composed of proteins, labeled I through IV in Figure 1, and the aggregation of these four complexes, together with associated mobile, accessory electron carriers, is called the electron transport chain. The electron transport chain is present in multiple copies in the inner mitochondrial membrane of eukaryotes and the plasma membrane of prokaryotes. Note, however, that the electron transport chain of prokaryotes may not require oxygen as some live in anaerobic ...
Biological Electron Microscopy: Theory, Techniques, and Troubleshooting By Michael J. Dykstra, Laura E. Reuss2013 | 534 Pages | ISBN: 1461348560 | PDF | 16
Participants: Pascale Gaudet, Michelle Gwinn-Giglio, Jennifer Deegan, Jim Hu, Debby Siegele, Ingrid Keseler. Since last meeting we discussed on email the problem the electron transport to some of the proteins in the photosynthetic electron transport chain are processes and some are really just functions. It seemed like we could waste a lot of time essentially splitting hairs trying to work out which were functions and which were processes, when currently so many are missing altogether. It is hoped that very soon the GO will include links between the function and process ontologies, and this change would make it much easier to make a correct representation of this area of biology as the full set of terms would be linked together and visible as a group in a single window of the user interface. This change to MF-BP links has not happened yet but is taking place as a pilot project. Therefore we discussed the idea of initially making a flat list of the functions and smaller processes that should come ...
Escherichia coli contains a versatile respiratory chain that oxidizes 10 different electron donor substrates and transfers the electrons to terminal reductases or oxidases for the reduction of six different electron acceptors. Salmonella is able to use two more electron acceptors. The variation is further increased by the presence of isoenzymes for some substrates. A large number of respiratory pathways can be established by combining different electron donors and acceptors. The respiratory dehydrogenases use quinones as the electron acceptors that are oxidized by the terminal reductase and oxidases. The enzymes vary largely with respect to their composition, architecture, membrane topology, and the mode of energy conservation. Most of the energy-conserving dehydrogenases (FdnGHI, HyaABC, HybCOAB, and others) and the terminal reductases (CydAB, NarGHI, and others) form a proton potential (Δp) by a redox-loop mechanism. Two enzymes (NuoA-N and CyoABCD) couple the redox energy to proton translocation by
TY - JOUR. T1 - Contrasting photoinduced electron-transfer properties of two closely related, rigidly linked porphyrin-quinone dyads. AU - Sumida, John P.. AU - Liddell, Paul A.. AU - Lin, Su. AU - Macpherson, Alisdair N.. AU - Seely, Gilbert R.. AU - Moore, Ana L. AU - Moore, Thomas A. AU - Gust, John Devens. PY - 1998/7/9. Y1 - 1998/7/9. N2 - Two closely related, rigidly linked porphyrin-naphthoquinone dyads have been prepared and studied using time-resolved fluorescence and absorption methods. Dyad 1, whose quinone carbonyl groups are relatively close to the porphyrin macrocycle, exhibits photoinduced electron-transfer rate constants that are virtually independent of solvent dielectric constant and temperature within the range 77-295 K. Dyad 2, which has a similar donor-acceptor linkage but whose quinone carbonyl groups are ∼2 Å farther from the porphyrin, features photoinduced electron-transfer rate constants that decrease with decreasing solvent dielectric constant. Electron transfer in ...
View Notes - Electron Transport System from BIO 101 at Texas State. final electron acceptor is an oxygen atom. In their energy-depleted condition, the electrons unite with an oxygen atom. The
There are at least two photosynthetic cyclic electron transport (CET) pathways in most C(3) plants: the NAD(P)H dehydrogenase (NDH)-dependent pathway and a pathway dependent upon putative ferredoxin:plastoquinone oxidoreductase (FQR) activity. While the NDH complex has been identified, and shown to …
During a multistep synthesis, protecting groups are often employed for the amino group to reduce its basicity and nucleophilicity. The benzyl group is a common protecting group for amines. However, its deprotection involves harsh chemical conditions. ^ The purpose of this research is (1) seek a mild debenzylation method by a visible light induced electron transfer reaction, and (2) develop a novel visible light removable quinoline type protecting group for amines which offers some advantages over the benzyl group. ^ Photochemical debenzylation of benzylated tertiary amines was carried out using an inexpensive spotlight, a dye as a photosensitizer and acetonitrile-water as solvent. Illumination under nitrogen led to the cleanest reaction, though under oxygen the reaction was faster. The reaction was about ten times faster in the presence of a cupric salt. The presumed mechanism of reaction involves a photoinduced electron transfer, and a coordination involving cupric ion seems to improve the quantum
wp-content/uploads/2017/10/blank-box.png 0 0 Coraline Tao /wp-content/uploads/2017/10/blank-box.png Coraline Tao2021-07-31 22:39:442021-07-31 22:48:22Mechanistic insights about electrochemical proton-coupled electron transfer derived from a vibrational probe ...
Spin-polarized electron transport through zigzag-edged graphene nanoislands is studied within the framework of the Pariser-Parr-Pople Hamiltonian. By including both short- and long-range electron-electron interactions, the electron conductance is calculated self-consistently for the hexagonal model on various substrates from which we are able to identify the effects of the many-body interactions in the electron transport. For the system in its lowest antiferromagnetic (AFM) state, the long-range interactions are shown to have negligible effect on the electron transport in the low-energy region in which the conductance is found quenched mainly by the short-range interactions. As the system is excited to its second AFM state, the short- and long-range interactions are found to have opposite effects on the electron transmission, i.e., the electron transmission is found to increase with either the suppression of the long-range interactions or the enhancement of the short-range interactions. When the ...
We discuss the conductance of a molecular bridge between mesoscopic electrodes supporting low-dimensional transport and bearing an internal structure. As an example for such nanoelectrodes we assume semi-infinite (carbon) nanotubes. In the Landauer scattering matrix approach, we show that the conductance of this hybrid is very sensitive to the geometry of the contact, unlike the usual behavior in the presence of bulk electrodes. ...
The electron transport chain takes place in the membranes of the mitochondria in eukaryotic cells. Electron transport is the last stage of cell respiration. The chain passes high-energy electrons...
Frey BL, Ladror DT, Sondalle SB, Krusemark CJ, Jue AL, Coon JJ, Smith LM. Chemical Derivatization of Peptide Carboxyl Groups for Highly Efficient Electron Transfer Dissociation. Journal of the American Society for Mass Spectrometry. 2013 ;24:1710-1721. ...
Frey B.L, Ladror D.T, Sondalle S.B, Krusemark C.J, Jue A.L, Coon J.J, Smith L.M. 2013. Chemical Derivatization of Peptide Carboxyl Groups for Highly Efficient Electron Transfer Dissociation. Journal of the American Society for Mass Spectrometry. 24:1710-1721. ...
Frey B.L, Ladror D.T, Sondalle S.B, Krusemark C.J, Jue A.L, Coon J.J, Smith L.M. 2013. Chemical Derivatization of Peptide Carboxyl Groups for Highly Efficient Electron Transfer Dissociation. Journal of the American Society for Mass Spectrometry. 24:1710-1721. ...
Electron transport system can define as a mechanism of cellular respiration that occurs in the inner membrane of mitochondria, which produces ATP by the transfer of electron from one carrier to another.
TY - JOUR. T1 - Energy and electron transfer in a poly(fluorene-alt-phenylene) bearing perylenediimides as pendant electron acceptor groups. AU - Gómez, R.. AU - Veldman, D.. AU - Blanco, R.. AU - Seoane, C.. AU - Segura, J.L.. AU - Janssen, R.A.J.. PY - 2007. Y1 - 2007. N2 - We describe the synthesis and characterization of a novel poly(fluorene-alt-phenylene) substituted with perylenediimide (PDI) moieties as pendant groups. Cyclic voltammetry experiments show the amphoteric nature of the material, which combines the good electron donor ability of the polymeric chain with the acceptor properties of the pendant PDI moieties. Absorption spectroscopy suggests the presence of PDI aggregates, whereas the emission spectra show a strong emission quenching of both the polymeric backbone and the PDI units. Further investigation on the energy and/or electron-transfer processes involved is carried out by temperature-dependent excitation spectra and photoluminescence lifetimes. These studies show the ...
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In this work, investigations on the transport of electrons on liquid helium films through narrow channels using suitable substrate structures, microfabricated on a silicon wafer which resembles Field E ect Transistors (we call it He-FET) have been presented. The sample has Source and Drain,br /,regions, separated by a Gate structure, which consists of 2 gold electrodes with a narrow gap (channel) through which the electron transport takes place. The electron densities on the source and drain are determined directly by electrical method. For time-resolved measurements, a pulse of electrons from a small lament is rst collected on the source area, and then the passage of this pulse through the channel of the split gate towards the drain is monitored. This allows determining the electron transport of surface state electrons in channels of various dimensions and for a wide range of electron densities. The study of the potential distribution across the He-FET sample results,br /,in a new model of ...
Highly (001)-textured, photoactive WSe2 thin films have been prepared by an amorphous solid-liquid-crystalline solid process promoted by palladium. By increasing the thickness of the Pd promoter film (≥10 nm) the structure and texture of the WSe2 films can be improved significantly. However, these as-crystallized WSe2 films are only weakly photoactive in a 0.5 М H2SO4 electrolyte under AM 1.5 solar irradiation which we attribute to an inefficient photogenerated charge transfer across the WSe2/electrolyte interface via the prevailing van der Waals planes of the WSe2 crystallites. In this work photochemically deposited platinum on the p-type WSe2 photocathode is used for an efficient electron transfer thus inducing the hydrogen evolution reaction. Upon illuminating the WSe2 photocathodes in a Pt-ion containing electrolyte, the photogenerated electrons reduce Pt+ to Pt leading to the precipitation of Pt islands, preferentially at edge steps of the WSe2, i.e. at the grain boundaries of the WSe2
In photosynthesis , 26 protein complexes and enzymes are required to go through the light and light independent reactions, a chemical process that transforms sunlight into chemical energy, to get glucose as end product , a metabolic intermediate for cell respiration. A good part of the protein complexes are uniquely used in photosynthesis. The pathway must go all the way through, and all steps are required, otherwise glucose is not produced. Also, in the oxygen evolving complex, which splits water into electrons, protons, and CO2, if the light-induced electron transfer reactions do not go all the five steps through, no oxygen, no protons and electrons are produced, no advanced life would be possible on earth. So, photosynthesis is a interdependent system, that could not have evolved, since all parts had to be in place right from the beginning. It contains many interdependent systems composed of parts that would be useless without the presence of all the other necessary parts. In these systems, ...
Electron Transport Chain. The oxidation of glucose carbon atoms is carried out in glycolysis and the citric acid cycle, and the produced protons and electrons are stored in NADH and FADH2 molecules.
A major challenge associated with intrinsic bioremediation is demonstrating its success. The consumption of electron acceptors during bioremediation of hydrocarbons and other contaminants can result in shifts in the predominant terminal electron-accepting processes (TEAPs), which may be useful for monitoring. Because traditional assessment tools have disadvantages, an accurate indicator of TEAPs is still needed. Acetate thresholds were evaluated to test the hypothesis that characteristic ranges of acetate thresholds may exist for different TEAPs and be useful as a bioremediation monitoring tool. Acetate thresholds established by pure microbial batch cultures using different TEAPs were measured experimentally. Furthermore, the factors controlling acetate thresholds were investigated using a microbial respiration model. Acetate thresholds increased in the order: Fe(III),Mn(IV)=nitrate,sulfate,CO2. Modeling results indicated that acetate thresholds were controlled by kinetics under Mn(IV)-, ...
ETC: Advanced Look --, 4.) ATP Synthase ATP synthase is considered a part of the electron transport chain, but it is not involved in the transport of electrons. ATP synthase uses the proton gradient created by the ETC to synthesize ATP. Clicking on each of the thumbnail images will bring up a larger, labeled version of the described scene.. To see the Flash movie for the following sequence of images, click here.. ...
After the Krebs cycle is completed, oxygen enters the respiration pathway as the electron acceptor at the end of the electron transport chain.
Genome mapping of Mtb revealed that the genome contains genes encoding for a high number of cytochrome P450 enzymes (CYPs or P450s) that are involved in very specific and physiologically relevant pathways for the bacteria. Therefore, cytochrome P450 enzymes are investigated as targets for novel therapeutic agents. Sandra Ortega Ugalde and her AIMMS colleagues identified the reaction catalyzed by one of these CYPs, CYP130A1, shedding light into its physiological role. Furthermore, catalytic activity of mycobacterial CYPs is dependent on electron transfer from a NAD (P)H-ferredoxin-reductase and a ferredoxin. Ortega and her colleagues have improved the basic understanding of the selectivity, biochemical properties, and function of the iron-sulfur cluster-containing ferredoxin proteins in Mtb essential for the reconstitution of the cognate CYP catalytic system to aid in the development of new antibiotics. Finally, they are also conducting collaborative studies to synthetize specific and potent ...
in an adjacent domain corresponds to a change in the description of the state from one little group k to another little group k′. Although this change of momentum is forbidden in a bulk wurtzite crystal, it becomes allowed in the OSL because of the wedge interface boundaries that give rise to the lossless refraction phenomenon (15). The interdomain electron transfer can be described as a transition from one Pmn21 symmetry BZ (see fig. S6) to another rotated by π/3, just as in Fig. 6. The intradomain transport obeys the translation symmetry of the space group Pmn21. However, this translation group is not an invariant subgroup of the P63cm supergroup corresponding to the OSL because Pmn21 does not have a sixfold symmetry axis. Thus, k changes can occur during interdomain propagation because k is not a constant of motion of the OSL. The inter- and intradomain propagation outlined above describes all propagation in the OSL. It is therefore not necessary to invoke the Bloch formalism for the ...