The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)
A complex of enzymes and PROTON PUMPS located on the inner membrane of the MITOCHONDRIA and in bacterial membranes. The protein complex provides energy in the form of an electrochemical gradient, which may be used by either MITOCHONDRIAL PROTON-TRANSLOCATING ATPASES or BACTERIAL PROTON-TRANSLOCATING ATPASES.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
Stable elementary particles having the smallest known negative charge, present in all elements; also called negatrons. Positively charged electrons are called positrons. The numbers, energies and arrangement of electrons around atomic nuclei determine the chemical identities of elements. Beams of electrons are called CATHODE RAYS.
The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.
The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.
A flavoprotein and iron sulfur-containing oxidoreductase complex that catalyzes the conversion of UBIQUINONE to ubiquinol. In MITOCHONDRIA the complex also couples its reaction to the transport of PROTONS across the internal mitochondrial membrane. The NADH DEHYDROGENASE component of the complex can be isolated and is listed as EC 1.6.99.3.
Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.
The synthesis by organisms of organic chemical compounds, especially carbohydrates, from carbon dioxide using energy obtained from light rather than from the oxidation of chemical compounds. Photosynthesis comprises two separate processes: the light reactions and the dark reactions. In higher plants; GREEN ALGAE; and CYANOBACTERIA; NADPH and ATP formed by the light reactions drive the dark reactions which result in the fixation of carbon dioxide. (from Oxford Dictionary of Biochemistry and Molecular Biology, 2001)
A multisubunit enzyme complex that contains CYTOCHROME B GROUP; CYTOCHROME C1; and iron-sulfur centers. It catalyzes the oxidation of ubiquinol to UBIQUINONE, and transfers the electrons to CYTOCHROME C. In MITOCHONDRIA the redox reaction is coupled to the transport of PROTONS across the inner mitochondrial membrane.
A multisubunit enzyme complex containing CYTOCHROME A GROUP; CYTOCHROME A3; two copper atoms; and 13 different protein subunits. It is the terminal oxidase complex of the RESPIRATORY CHAIN and collects electrons that are transferred from the reduced CYTOCHROME C GROUP and donates them to molecular OXYGEN, which is then reduced to water. The redox reaction is simultaneously coupled to the transport of PROTONS across the inner mitochondrial membrane.
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)
An antibiotic substance produced by Streptomyces species. It inhibits mitochondrial respiration and may deplete cellular levels of ATP. Antimycin A1 has been used as a fungicide, insecticide, and miticide. (From Merck Index, 12th ed)
A pre-emergent herbicide.
Hemeproteins whose characteristic mode of action involves transfer of reducing equivalents which are associated with a reversible change in oxidation state of the prosthetic group. Formally, this redox change involves a single-electron, reversible equilibrium between the Fe(II) and Fe(III) states of the central iron atom (From Enzyme Nomenclature, 1992, p539). The various cytochrome subclasses are organized by the type of HEME and by the wavelength range of their reduced alpha-absorption bands.
A flavoprotein oxidase complex that contains iron-sulfur centers. It catalyzes the oxidation of SUCCINATE to fumarate and couples the reaction to the reduction of UBIQUINONE to ubiquinol.
The rate dynamics in chemical or physical systems.
The directed transport of ORGANELLES and molecules along nerve cell AXONS. Transport can be anterograde (from the cell body) or retrograde (toward the cell body). (Alberts et al., Molecular Biology of the Cell, 3d ed, pG3)
Porphyrin derivatives containing magnesium that act to convert light energy in photosynthetic organisms.
A lipid-soluble benzoquinone which is involved in ELECTRON TRANSPORT in mitochondrial preparations. The compound occurs in the majority of aerobic organisms, from bacteria to higher plants and animals.
Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.
The 8-hydroxy derivatives inhibit various enzymes and their halogenated derivatives, though neurotoxic, are used as topical anti-infective agents, among other uses.
A botanical insecticide that is an inhibitor of mitochondrial electron transport.
Electron transfer through the cytochrome system liberating free energy which is transformed into high-energy phosphate bonds.
The movement of ions across energy-transducing cell membranes. Transport can be active, passive or facilitated. Ions may travel by themselves (uniport), or as a group of two or more ions in the same (symport) or opposite (antiport) directions.
The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)
The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.
The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)
Chemical agents that uncouple oxidation from phosphorylation in the metabolic cycle so that ATP synthesis does not occur. Included here are those IONOPHORES that disrupt electron transfer by short-circuiting the proton gradient across mitochondrial membranes.
Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.
Polyunsaturated side-chain quinone derivative which is an important link in the electron transport chain of green plants during the photosynthetic conversion of light energy by photophosphorylation into the potential energy of chemical bonds.
A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
Inorganic salts of HYDROGEN CYANIDE containing the -CN radical. The concept also includes isocyanides. It is distinguished from NITRILES, which denotes organic compounds containing the -CN radical.
A flavoprotein and iron sulfur-containing oxidoreductase that catalyzes the oxidation of NADH to NAD. In eukaryotes the enzyme can be found as a component of mitochondrial electron transport complex I. Under experimental conditions the enzyme can use CYTOCHROME C GROUP as the reducing cofactor. The enzyme was formerly listed as EC 1.6.2.1.
A large multisubunit protein complex found in the THYLAKOID MEMBRANE. It uses light energy derived from LIGHT-HARVESTING PROTEIN COMPLEXES to catalyze the splitting of WATER into DIOXYGEN and of reducing equivalents of HYDROGEN.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Plant cell inclusion bodies that contain the photosynthetic pigment CHLOROPHYLL, which is associated with the membrane of THYLAKOIDS. Chloroplasts occur in cells of leaves and young stems of plants. They are also found in some forms of PHYTOPLANKTON such as HAPTOPHYTA; DINOFLAGELLATES; DIATOMS; and CRYPTOPHYTA.
Derivatives of SUCCINIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain a 1,4-carboxy terminated aliphatic structure.
A flavoprotein containing oxidoreductase that catalyzes the dehydrogenation of SUCCINATE to fumarate. In most eukaryotic organisms this enzyme is a component of mitochondrial electron transport complex II.
An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.
A large multisubunit protein complex that is found in the THYLAKOID MEMBRANE. It uses light energy derived from LIGHT-HARVESTING PROTEIN COMPLEXES to drive electron transfer reactions that result in either the reduction of NADP to NADPH or the transport of PROTONS across the membrane.
Membranous cisternae of the CHLOROPLAST containing photosynthetic pigments, reaction centers, and the electron-transport chain. Each thylakoid consists of a flattened sac of membrane enclosing a narrow intra-thylakoid space (Lackie and Dow, Dictionary of Cell Biology, 2nd ed). Individual thylakoids are interconnected and tend to stack to form aggregates called grana. They are found in cyanobacteria and all plants.
A protein complex that includes CYTOCHROME B6 and CYTOCHROME F. It is found in the THYLAKOID MEMBRANE and plays an important role in process of PHOTOSYNTHESIS by transferring electrons from PLASTOQUINONE to PLASTOCYANIN or CYTOCHROME C6. The transfer of electrons is coupled to the transport of PROTONS across the membrane.
The metabolic process of all living cells (animal and plant) in which oxygen is used to provide a source of energy for the cell.
A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)
Protein complexes that take part in the process of PHOTOSYNTHESIS. They are located within the THYLAKOID MEMBRANES of plant CHLOROPLASTS and a variety of structures in more primitive organisms. There are two major complexes involved in the photosynthetic process called PHOTOSYSTEM I and PHOTOSYSTEM II.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of signal transduction and gene expression, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS.
Inorganic salts of the hypothetical acid, H3Fe(CN)6.
A barbiturate with hypnotic and sedative properties (but not antianxiety). Adverse effects are mainly a consequence of dose-related CNS depression and the risk of dependence with continued use is high. (From Martindale, The Extra Pharmacopoeia, 30th ed, p565)
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
A group of cytochromes with covalent thioether linkages between either or both of the vinyl side chains of protoheme and the protein. (Enzyme Nomenclature, 1992, p539)
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
A group of oxidoreductases that act on NADH or NADPH. In general, enzymes using NADH or NADPH to reduce a substrate are classified according to the reverse reaction, in which NAD+ or NADP+ is formally regarded as an acceptor. This subclass includes only those enzymes in which some other redox carrier is the acceptor. (Enzyme Nomenclature, 1992, p100) EC 1.6.
A large group of membrane transport proteins that shuttle MONOSACCHARIDES across CELL MEMBRANES.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Iron-containing proteins that transfer electrons, usually at a low potential, to flavoproteins; the iron is not present as in heme. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
Cytochromes (electron-transporting proteins) with protoheme (HEME B) as the prosthetic group.
A highly poisonous compound that is an inhibitor of many metabolic processes, but has been shown to be an especially potent inhibitor of heme enzymes and hemeproteins. It is used in many industrial processes.
A water-soluble, colorless crystal with an acid taste that is used as a chemical intermediate, in medicine, the manufacture of lacquers, and to make perfume esters. It is also used in foods as a sequestrant, buffer, and a neutralizing agent. (Hawley's Condensed Chemical Dictionary, 12th ed, p1099; McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1851)
Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)
The mitochondria of the myocardium.
Transport proteins that carry specific substances in the blood or across cell membranes.
The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.
At low concentrations, this compound inhibits reduction of conventional hydrophilic electron acceptors, probably acting as a plastoquinone antagonist. At higher concentrations, it acts as an electron acceptor, intercepting electrons either before or at the site of its inhibitory activity.
Proteins found in any species of bacterium.
The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight [1.00784; 1.00811]. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.
A copper-containing plant protein that is a fundamental link in the electron transport chain of green plants during the photosynthetic conversion of light energy by photophosphorylation into the potential energy of chemical bonds.
Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.
The use of light to convert ADP to ATP without the concomitant reduction of dioxygen to water as occurs during OXIDATIVE PHOSPHORYLATION in MITOCHONDRIA.
A genus of gram-negative, anaerobic, rod-shaped bacteria isolated from the bovine RUMEN, the human gingival sulcus, and dental PULPITIS infections.
A saprophytic bacterium widely distributed in soil and dust and on plants.
The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
A phylum of oxygenic photosynthetic bacteria comprised of unicellular to multicellular bacteria possessing CHLOROPHYLL a and carrying out oxygenic PHOTOSYNTHESIS. Cyanobacteria are the only known organisms capable of fixing both CARBON DIOXIDE (in the presence of light) and NITROGEN. Cell morphology can include nitrogen-fixing heterocysts and/or resting cells called akinetes. Formerly called blue-green algae, cyanobacteria were traditionally treated as ALGAE.
Mitochondria in hepatocytes. As in all mitochondria, there are an outer membrane and an inner membrane, together creating two separate mitochondrial compartments: the internal matrix space and a much narrower intermembrane space. In the liver mitochondrion, an estimated 67% of the total mitochondrial proteins is located in the matrix. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p343-4)
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.
A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.
Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)
Vesicles that are involved in shuttling cargo from the interior of the cell to the cell surface, from the cell surface to the interior, across the cell or around the cell to various locations.
Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.
An oral anticoagulant that interferes with the metabolism of vitamin K. It is also used in biochemical experiments as an inhibitor of reductases.
Cytochromes f are found as components of the CYTOCHROME B6F COMPLEX. They play important role in the transfer of electrons from PHOTOSYSTEM I to PHOTOSYSTEM II.
A genus of gram-negative, facultatively anaerobic rods. It is a saprophytic, marine organism which is often isolated from spoiling fish.
A group of proteins possessing only the iron-sulfur complex as the prosthetic group. These proteins participate in all major pathways of electron transport: photosynthesis, respiration, hydroxylation and bacterial hydrogen and nitrogen fixation.
Complexes containing CHLOROPHYLL and other photosensitive molecules. They serve to capture energy in the form of PHOTONS and are generally found as components of the PHOTOSYSTEM I PROTEIN COMPLEX or the PHOTOSYSTEM II PROTEIN COMPLEX.
A proton ionophore that is commonly used as an uncoupling agent in biochemical studies.
Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
A form-genus of unicellular CYANOBACTERIA in the order Chroococcales. None of the strains fix NITROGEN, there are no gas vacuoles, and sheath layers are never produced.
Compounds based on fumaric acid.
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
The property of emitting radiation while being irradiated. The radiation emitted is usually of longer wavelength than that incident or absorbed, e.g., a substance can be irradiated with invisible radiation and emit visible light. X-ray fluorescence is used in diagnosis.
Organic compounds that contain two nitro groups attached to a phenol.
Mitochondria of skeletal and smooth muscle. It does not include myocardial mitochondria for which MITOCHONDRIA, HEART is available.
Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.
A proton ionophore. It is commonly used as an uncoupling agent and inhibitor of photosynthesis because of its effects on mitochondrial and chloroplast membranes.
The chemical reactions involved in the production and utilization of various forms of energy in cells.
Life or metabolic reactions occurring in an environment containing oxygen.
An enzyme that catalyzes the oxidation and reduction of FERREDOXIN or ADRENODOXIN in the presence of NADP. EC 1.18.1.2 was formerly listed as EC 1.6.7.1 and EC 1.6.99.4.
A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.
Hydrocarbon rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.
NAD(P)H:(quinone acceptor) oxidoreductases. A family that includes three enzymes which are distinguished by their sensitivity to various inhibitors. EC 1.6.99.2 (NAD(P)H DEHYDROGENASE (QUINONE);) is a flavoprotein which reduces various quinones in the presence of NADH or NADPH and is inhibited by dicoumarol. EC 1.6.99.5 (NADH dehydrogenase (quinone)) requires NADH, is inhibited by AMP and 2,4-dinitrophenol but not by dicoumarol or folic acid derivatives. EC 1.6.99.6 (NADPH dehydrogenase (quinone)) requires NADPH and is inhibited by dicoumarol and folic acid derivatives but not by 2,4-dinitrophenol.
Proteins encoded by the mitochondrial genome or proteins encoded by the nuclear genome that are imported to and resident in the MITOCHONDRIA.
Energy that is generated by the transfer of protons or electrons across an energy-transducing membrane and that can be used for chemical, osmotic, or mechanical work. Proton-motive force can be generated by a variety of phenomena including the operation of an electron transport chain, illumination of a PURPLE MEMBRANE, and the hydrolysis of ATP by a proton ATPase. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed, p171)
Organic or inorganic compounds that contain the -N3 group.
A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.
A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)
Elements of limited time intervals, contributing to particular results or situations.
A widely cultivated plant, native to Asia, having succulent, edible leaves eaten as a vegetable. (From American Heritage Dictionary, 1982)
A closely related group of toxic substances elaborated by various strains of Streptomyces. They are 26-membered macrolides with lactone moieties and double bonds and inhibit various ATPases, causing uncoupling of phosphorylation from mitochondrial respiration. Used as tools in cytochemistry. Some specific oligomycins are RUTAMYCIN, peliomycin, and botrycidin (formerly venturicidin X).
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.
Established cell cultures that have the potential to propagate indefinitely.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
A lipid cofactor that is required for normal blood clotting. Several forms of vitamin K have been identified: VITAMIN K 1 (phytomenadione) derived from plants, VITAMIN K 2 (menaquinone) from bacteria, and synthetic naphthoquinone provitamins, VITAMIN K 3 (menadione). Vitamin K 3 provitamins, after being alkylated in vivo, exhibit the antifibrinolytic activity of vitamin K. Green leafy vegetables, liver, cheese, butter, and egg yolk are good sources of vitamin K.
A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).
A type of TRANSMISSION ELECTRON MICROSCOPY in which the object is examined directly by an extremely narrow electron beam scanning the specimen point-by-point and using the reactions of the electrons that are transmitted through the specimen to create the image. It should not be confused with SCANNING ELECTRON MICROSCOPY.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
A dye used as a reagent in the determination of vitamin C.
A hydroxynaphthoquinone that has antimicrobial activity and is being used in antimalarial protocols.
Membrane proteins whose primary function is to facilitate the transport of negatively charged molecules (anions) across a biological membrane.
Highly reactive compounds produced when oxygen is reduced by a single electron. In biological systems, they may be generated during the normal catalytic function of a number of enzymes and during the oxidation of hemoglobin to METHEMOGLOBIN. In living organisms, SUPEROXIDE DISMUTASE protects the cell from the deleterious effects of superoxides.
Ions with the suffix -onium, indicating cations with coordination number 4 of the type RxA+ which are analogous to QUATERNARY AMMONIUM COMPOUNDS (H4N+). Ions include phosphonium R4P+, oxonium R3O+, sulfonium R3S+, chloronium R2Cl+
Membrane proteins whose primary function is to facilitate the transport of positively charged molecules (cations) across a biological membrane.
A genus of gram-negative, anaerobic, metal-reducing bacteria in the family Geobacteraceae. They have the ability to oxidize a variety of organic compounds, including AROMATIC HYDROCARBONS.
The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.
A cyclododecadepsipeptide ionophore antibiotic produced by Streptomyces fulvissimus and related to the enniatins. It is composed of 3 moles each of L-valine, D-alpha-hydroxyisovaleric acid, D-valine, and L-lactic acid linked alternately to form a 36-membered ring. (From Merck Index, 11th ed) Valinomycin is a potassium selective ionophore and is commonly used as a tool in biochemical studies.
Systems of enzymes which function sequentially by catalyzing consecutive reactions linked by common metabolic intermediates. They may involve simply a transfer of water molecules or hydrogen atoms and may be associated with large supramolecular structures such as MITOCHONDRIA or RIBOSOMES.
A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
Organelles of phototrophic bacteria which contain photosynthetic pigments and which are formed from an invagination of the cytoplasmic membrane.
A broad category of proteins involved in the formation, transport and dissolution of TRANSPORT VESICLES. They play a role in the intracellular transport of molecules contained within membrane vesicles. Vesicular transport proteins are distinguished from MEMBRANE TRANSPORT PROTEINS, which move molecules across membranes, by the mode in which the molecules are transported.
The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.
Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.
Inorganic salts of the hypothetical acid ferrocyanic acid (H4Fe(CN)6).
A carbodiimide that is used as a chemical intermediate and coupling agent in peptide synthesis. (From Hawley's Condensed Chemical Dictionary, 12th ed)
The parts of a macromolecule that directly participate in its specific combination with another molecule.
An electrochemical technique for measuring the current that flows in solution as a function of an applied voltage. The observed polarographic wave, resulting from the electrochemical response, depends on the way voltage is applied (linear sweep or differential pulse) and the type of electrode used. Usually a mercury drop electrode is used.
Identification and measurement of ELEMENTS and their location based on the fact that X-RAYS emitted by an element excited by an electron beam have a wavelength characteristic of that element and an intensity related to its concentration. It is performed with an electron microscope fitted with an x-ray spectrometer, in scanning or transmission mode.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
The voltage difference, normally maintained at approximately -180mV, across the INNER MITOCHONDRIAL MEMBRANE, by a net movement of positive charge across the membrane. It is a major component of the PROTON MOTIVE FORCE in MITOCHONDRIA used to drive the synthesis of ATP.
A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
A flavoprotein that reversibly catalyzes the oxidation of NADH or NADPH by various quinones and oxidation-reduction dyes. The enzyme is inhibited by dicoumarol, capsaicin, and caffeine.
The absence of light.
Inorganic salts of phosphoric acid.
A carboxy-lyase that plays a key role in photosynthetic carbon assimilation in the CALVIN-BENSON CYCLE by catalyzing the formation of 3-phosphoglycerate from ribulose 1,5-biphosphate and CARBON DIOXIDE. It can also utilize OXYGEN as a substrate to catalyze the synthesis of 2-phosphoglycolate and 3-phosphoglycerate in a process referred to as photorespiration.
Chelating agent and inhibitor of cellular respiration.
A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.
The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.
Spherical phototrophic bacteria found in mud and stagnant water exposed to light.
Cellular proteins and protein complexes that transport amino acids across biological membranes.
A species of GREEN ALGAE. Delicate, hairlike appendages arise from the flagellar surface in these organisms.
Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.
A plant genus of the family SOLANACEAE. Members contain NICOTINE and other biologically active chemicals; its dried leaves are used for SMOKING.
Cytochromes of the c type that are found in eukaryotic MITOCHONDRIA. They serve as redox intermediates that accept electrons from MITOCHONDRIAL ELECTRON TRANSPORT COMPLEX III and transfer them to MITOCHONDRIAL ELECTRON TRANSPORT COMPLEX IV.
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)
Inorganic or organic compounds containing trivalent iron.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
A plant genus of the family TILIACEAE. Some species in this genus are called Limetree which is nearly the same as the common name for lime (CITRUS AURANTIIFOLIA). Some people are allergic to the POLLEN.
A six carbon compound related to glucose. It is found naturally in citrus fruits and many vegetables. Ascorbic acid is an essential nutrient in human diets, and necessary to maintain connective tissue and bone. Its biologically active form, vitamin C, functions as a reducing agent and coenzyme in several metabolic pathways. Vitamin C is considered an antioxidant.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
A sulfhydryl reagent that is widely used in experimental biochemical studies.
Salts or esters of LACTIC ACID containing the general formula CH3CHOHCOOR.
Derivatives of the dimethylisoalloxazine (7,8-dimethylbenzo[g]pteridine-2,4(3H,10H)-dione) skeleton. Flavin derivatives serve an electron transfer function as ENZYME COFACTORS in FLAVOPROTEINS.
Negatively charged atoms, radicals or groups of atoms which travel to the anode or positive pole during electrolysis.
The various filaments, granules, tubules or other inclusions within mitochondria.
Acidic phospholipids composed of two molecules of phosphatidic acid covalently linked to a molecule of glycerol. They occur primarily in mitochondrial inner membranes and in bacterial plasma membranes. They are the main antigenic components of the Wassermann-type antigen that is used in nontreponemal SYPHILIS SERODIAGNOSIS.
Double-stranded DNA of MITOCHONDRIA. In eukaryotes, the mitochondrial GENOME is circular and codes for ribosomal RNAs, transfer RNAs, and about 10 proteins.
A genus of anaerobic, irregular spheroid-shaped METHANOSARCINALES whose organisms are nonmotile. Endospores are not formed. These archaea derive energy via formation of methane from acetate, methanol, mono-, di-, and trimethylamine, and possibly, carbon monoxide. Organisms are isolated from freshwater and marine environments.
Acrylic acids or acrylates which are substituted in the C-2 position with a methyl group.
Inorganic or organic salts and esters of nitric acid. These compounds contain the NO3- radical.
A family of MEMBRANE TRANSPORT PROTEINS that require ATP hydrolysis for the transport of substrates across membranes. The protein family derives its name from the ATP-binding domain found on the protein.
A condensation product of riboflavin and adenosine diphosphate. The coenzyme of various aerobic dehydrogenases, e.g., D-amino acid oxidase and L-amino acid oxidase. (Lehninger, Principles of Biochemistry, 1982, p972)
A genus of gram-negative, aerobic bacteria found in soil and water. Its organisms occur singly, in pairs or irregular clumps, and sometimes in chains of varying lengths.
Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.
Electric power supply devices which convert biological energy, such as chemical energy of metabolism or mechanical energy of periodic movements, into electrical energy.
Highly reactive molecules with an unsatisfied electron valence pair. Free radicals are produced in both normal and pathological processes. They are proven or suspected agents of tissue damage in a wide variety of circumstances including radiation, damage from environment chemicals, and aging. Natural and pharmacological prevention of free radical damage is being actively investigated.
An electron transport chain complex that catalyzes the transfer of electrons from SUCCINATE to CYTOCHROME C. It includes ELECTRON TRANSPORT COMPLEX II and ELECTRON TRANSPORT COMPLEX III.
An enzyme found in bacteria. It catalyzes the reduction of FERREDOXIN and other substances in the presence of molecular hydrogen and is involved in the electron transport of bacterial photosynthesis.
Type C cytochromes that are small (12-14 kD) single-heme proteins. They function as mobile electron carriers between membrane-bound enzymes in photosynthetic BACTERIA.
Used in the form of the hydrochloride as a reagent in ANALYTICAL CHEMISTRY TECHNIQUES.
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
A series of oxidative reactions in the breakdown of acetyl units derived from GLUCOSE; FATTY ACIDS; or AMINO ACIDS by means of tricarboxylic acid intermediates. The end products are CARBON DIOXIDE, water, and energy in the form of phosphate bonds.
An analytical method for detecting and measuring FLUORESCENCE in compounds or targets such as cells, proteins, or nucleotides, or targets previously labeled with FLUORESCENCE AGENTS.
The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The functional hereditary units of BACTERIA.
Membrane transporters that co-transport two or more dissimilar molecules in the same direction across a membrane. Usually the transport of one ion or molecule is against its electrochemical gradient and is "powered" by the movement of another ion or molecule with its electrochemical gradient.

Long-range oxidative damage to DNA: effects of distance and sequence. (1/5429)

INTRODUCTION: Oxidative damage to DNA in vivo can lead to mutations and cancer. DNA damage and repair studies have not yet revealed whether permanent oxidative lesions are generated by charges migrating over long distances. Both photoexcited *Rh(III) and ground-state Ru(III) intercalators were previously shown to oxidize guanine bases from a remote site in oligonucleotide duplexes by DNA-mediated electron transfer. Here we examine much longer charge-transport distances and explore the sensitivity of the reaction to intervening sequences. RESULTS: Oxidative damage was examined in a series of DNA duplexes containing a pendant intercalating photooxidant. These studies revealed a shallow dependence on distance and no dependence on the phasing orientation of the oxidant relative to the site of damage, 5'-GG-3'. The intervening DNA sequence has a significant effect on the yield of guanine oxidation, however. Oxidation through multiple 5'-TA-3' steps is substantially diminished compared to through other base steps. We observed intraduplex guanine oxidation by tethered *Rh(III) and Ru(III) over a distance of 200 A. The distribution of oxidized guanine varied as a function of temperature between 5 and 35 degrees C, with an increase in the proportion of long-range damage (> 100 A) occurring at higher temperatures. CONCLUSIONS: Guanines are oxidized as a result of DNA-mediated charge transport over significant distances (e.g. 200 A). Although long-range charge transfer is dependent on distance, it appears to be modulated by intervening sequence and sequence-dependent dynamics. These discoveries hold important implications with respect to DNA damage in vivo.  (+info)

Internal electron transfer between hemes and Cu(II) bound at cysteine beta93 promotes methemoglobin reduction by carbon monoxide. (2/5429)

Previous studies showed that CO/H2O oxidation provides electrons to drive the reduction of oxidized hemoglobin (metHb). We report here that Cu(II) addition accelerates the rate of metHb beta chain reduction by CO by a factor of about 1000. A mechanism whereby electron transfer occurs via an internal pathway coupling CO/H2O oxidation to Fe(III) and Cu(II) reduction is suggested by the observation that the copper-induced rate enhancement is inhibited by blocking Cys-beta93 with N-ethylmaleimide. Furthermore, this internal electron-transfer pathway is more readily established at low Cu(II) concentrations in Hb Deer Lodge (beta2His --> Arg) and other species lacking His-beta2 than in Hb A0. This difference is consistent with preferential binding of Cu(II) in Hb A0 to a high affinity site involving His-beta2, which is ineffective in promoting electron exchange between Cu(II) and the beta heme iron. Effective electron transfer is thus affected by Hb type but is not governed by the R left arrow over right arrow T conformational equilibrium. The beta hemes in Cu(II)-metHb are reduced under CO at rates close to those observed for cytochrome c oxidase, where heme and copper are present together in the oxygen-binding site and where internal electron transfer also occurs.  (+info)

Role of a novel photosystem II-associated carbonic anhydrase in photosynthetic carbon assimilation in Chlamydomonas reinhardtii. (3/5429)

Intracellular carbonic anhydrases (CA) in aquatic photosynthetic organisms are involved in the CO2-concentrating mechanism (CCM), which helps to overcome CO2 limitation in the environment. In the green alga Chlamydomonas reinhardtii, this CCM is initiated and maintained by the pH gradient created across the chloroplast thylakoid membranes by photosystem (PS) II-mediated electron transport. We show here that photosynthesis is stimulated by a novel, intracellular alpha-CA bound to the chloroplast thylakoids. It is associated with PSII on the lumenal side of the thylakoid membranes. We demonstrate that PSII in association with this lumenal CA operates to provide an ample flux of CO2 for carboxylation.  (+info)

Pathways of electron transfer in Escherichia coli DNA photolyase: Trp306 to FADH. (4/5429)

We describe the results of a series of theoretical calculations of electron transfer pathways between Trp306 and *FADH. in the Escherichia coli DNA photolyase molecule, using the method of interatomic tunneling currents. It is found that there are two conformationally orthogonal tryptophans, Trp359 and Trp382, between donor and acceptor that play a crucial role in the pathways of the electron transfer process. The pathways depend vitally on the aromaticity of tryptophans and the flavin molecule. The results of this calculation suggest that the major pathway of the electron transfer is due to a set of overlapping orthogonal pi-rings, which starts from the donor Trp306, runs through Trp359 and Trp382, and finally reaches the flavin group of the acceptor complex, FADH.  (+info)

Nitrate-dependent regulation of acetate biosynthesis and nitrate respiration by Clostridium thermoaceticum. (5/5429)

Nitrate has been shown to shunt the electron flow in Clostridium thermoaceticum from CO2 to nitrate, but it did not influence the levels of enzymes involved in the Wood-Ljungdahl pathway (J. M. Frostl, C. Seifritz, and H. L. Drake, J. Bacteriol. 178:4597-4603, 1996). Here we show that under some growth conditions, nitrate does in fact repress proteins involved in the Wood-Ljungdahl pathway. The CO oxidation activity in crude extracts of nitrate (30 mM)-supplemented cultures was fivefold less than that of nitrate-free cultures, while the H2 oxidation activity was six- to sevenfold lower. The decrease in CO oxidation activity paralleled a decrease in CO dehydrogenase (CODH) protein level, as confirmed by Western blot analysis. Protein levels of CODH in nitrate-supplemented cultures were 50% lower than those in nitrate-free cultures. Western blots analyses showed that nitrate also decreased the levels of the corrinoid iron-sulfur protein (60%) and methyltransferase (70%). Surprisingly, the decrease in activity and protein levels upon nitrate supplementation was observed only when cultures were continuously sparged. Northern blot analysis indicates that the regulation of the proteins involved in the Wood-Ljungdahl pathway by nitrate is at the transcriptional level. At least a 10-fold decrease in levels of cytochrome b was observed with nitrate supplementation whether the cultures were sparged or stoppered. We also detected nitrate-inducible nitrate reductase activity (2 to 39 nmol min-1 mg-1) in crude extracts of C. thermoaceticum. Our results indicate that nitrate coordinately represses genes encoding enzymes and electron transport proteins in the Wood-Ljungdahl pathway and activates transcription of nitrate respiratory proteins. CO2 also appears to induce expression of the Wood-Ljungdahl pathway genes and repress nitrate reductase activity.  (+info)

Structure of a cytochrome P450-redox partner electron-transfer complex. (6/5429)

The crystal structure of the complex between the heme- and FMN-binding domains of bacterial cytochrome P450BM-3, a prototype for the complex between eukaryotic microsomal P450s and P450 reductase, has been determined at 2.03 A resolution. The flavodoxin-like flavin domain is positioned at the proximal face of the heme domain with the FMN 4.0 and 18.4 A from the peptide that precedes the heme-binding loop and the heme iron, respectively. The heme-binding peptide represents the most efficient and coupled through-bond electron pathway to the heme iron. Substantial differences between the FMN-binding domains of P450BM-3 and microsomal P450 reductase, observed around the flavin-binding sites, are responsible for different redox properties of the FMN, which, in turn, control electron flow to the P450.  (+info)

Multiple pathways for ultrafast transduction of light energy in the photosynthetic reaction center of Rhodobacter sphaeroides. (7/5429)

A pathway of electron transfer is described that operates in the wild-type reaction center (RC) of the photosynthetic bacterium Rhodobacter sphaeroides. The pathway does not involve the excited state of the special pair dimer of bacteriochlorophylls (P*), but instead is driven by the excited state of the monomeric bacteriochlorophyll (BA*) present in the active branch of pigments along which electron transfer occurs. Pump-probe experiments were performed at 77 K on membrane-bound RCs by using different excitation wavelengths, to investigate the formation of the charge separated state P+HA-. In experiments in which P or BA was selectively excited at 880 nm or 796 nm, respectively, the formation of P+HA- was associated with similar time constants of 1.5 ps and 1. 7 ps. However, the spectral changes associated with the two time constants are very different. Global analysis of the transient spectra shows that a mixture of P+BA- and P* is formed in parallel from BA* on a subpicosecond time scale. In contrast, excitation of the inactive branch monomeric bacteriochlorophyll (BB) and the high exciton component of P (P+) resulted in electron transfer only after relaxation to P*. The multiple pathways for primary electron transfer in the bacterial RC are discussed with regard to the mechanism of charge separation in the RC of photosystem II from higher plants.  (+info)

Purified fusion enzyme between rat cytochrome P4501A1 and yeast NADPH-cytochrome P450 oxidoreductase. (8/5429)

A genetically engineered fusion enzyme between rat P4501A1 and yeast P450 reductase in the microsomal fraction of the recombinant yeast AH22/pAFCR1 was purified. The purified enzyme showed a typical CO-difference spectrum of P4501A1 and a single band with an apparent molecular weight of 125,000 on sodium dodecyl sulfate polyacrylamide gel electrophoresis. This agreed with the molecular weight of 131,202 calculated from the amino acid sequence. The purified enzyme showed both 7-ethoxycoumarin o-deethylase activity and horse heart cytochrome c reductase activity in the presence of NADPH. The 7-ethoxycoumarin o-deethylase activity depended on the species of lipid used for the reconstitution of the purified fusion enzyme although the purified enzyme showed the activity without reconstitution. The purified fusion enzyme had the Km value of 26 microM for 7-ethoxycoumarin and the maximal turnover rate of 29 mol product/min/mol enzyme at 30 degrees C.  (+info)

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 ...
Electron transport driven proton pumps[edit]. Electron Transport Complex I[edit]. Main article: NADH dehydrogenase (ubiquinone) ... This proton pump is driven by electron transport and catalyzes the transfer of electrons from plastoquinol to plastocyanin. The ... Electron Transport Complex IV[edit]. Main article: Cytochrome c oxidase. Complex IV (EC 1.9.3.1) (also referred to as ... Electron Transport Complex III[edit]. Main article: Coenzyme Q - cytochrome c reductase ...
FADH2 is also oxidized into H+ ions, electrons, and FAD. As those electrons travel farther through the electron transport chain ... Main article: Electron transport chain. NADH is oxidized into NAD+, H+ ions, and electrons by an enzyme. ... The electrons from each NADH molecule can form a total of 3 ATPs from ADPs and phosphate groups through the electron transport ... The electron transport chain requires a varying supply of electrons in order to properly function and generate ATP. However, ...
Electron transport chain, and humanin[edit]. It was originally incorrectly believed that the mitochondrial genome contained ... all of them encoding proteins of the electron transport chain. However, in 2001, a 14th biologically active protein called ... to damage from free oxygen radicals from mistakes that occur during the production of ATP through the electron transport chain ...
See electron transport chain.. *Cytochrome c oxidases from bacteria and mitochondria. Electrochemical potential-driven ... Membrane protein structures can be determined by X-ray crystallography, electron microscopy or NMR spectroscopy.[7] The most ... FadL outer membrane protein transport family, including Fatty acid transporter FadL (n=14,S=14) ... Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They ...
... electrons are ejected and transferred through electron transport chains (ETCs). Some electrons form Fe-S proteins in electron ... The Reaction Center Photochemistry and Electron Transport". Photosynthesis. Advances in Photosynthesis and Respiration. 10. pp ... Cytochrome c-551 then passes the electrons down the electron chain. P840 is returned to its reduced state by the oxidation of ... Green sulfur bacteria use sulfide ions, hydrogen or ferrous iron as electron donors and the process is mediated by the Type I ...
Electron transport chain (ETC)[change , change source]. Main article: Electron transport chain ... It has four stages known as glycolysis, Link reaction, the Krebs cycle, and the electron transport chain. This produces ATP ... and about 34 from the electron transport chain).[1] However, the process actually makes less energy (ATP) because of losses ... are pumped inside the mitochondria using energy that electrons release. Eventually, the electrons powering the pumping of ...
... that aid in the electron transport chain's ability to produce a proton gradient across the inner mitochondrial membrane.[13] ... "Electron Transport Chain (Overview)" (PDF). CSUN.edu. Retrieved 4 April 2013.. ... It is this energy coupling and phosphorylation of ADP to ATP that gives the electron transport chain the name oxidative ... During the initial phases of glycolysis and the TCA cycle, cofactors such as NAD+ donate and accept electrons[12] ...
The total equation for the electron transport chain is: N. A. D. H. +. 11. H. +. (. m. a. t. r. i. x. ). +. 1. /. 2. O. 2. ⟶. N ... In the electron transport chain, Complex I (CI) catalyzes the reduction of ubiquinone (UQ) to ubiquinol (UQH2) by the transfer ... Similar to the electron transport chain, the light-dependent reactions of photosynthesis pump protons into the thylakoid lumen ... The process that occurs is similar to the Q-cycle in Complex III of the electron transport chain. In the first reaction, PQH2 ...
Mason HS, Fowlks WK, Peterson E (1955). "Oxygen transfer and electron transport by the phenolase complex". J. Am. Chem. Soc. 77 ...
Hannemann F, Bichet A, Ewen KM, Bernhardt R (March 2007). "Cytochrome P450 systems--biological variations of electron transport ...
These molecules pass electrons to an electron transport chain, which uses the energy released to create a proton gradient ... These electrons travel down an electron transport chain, causing protons to be actively pumped across the thylakoid membrane ... The energy from the electron movement through electron transport chains cross through ATP synthase which allows the proton to ... The carriers pass electrons to the electron transport chain (ETC) in the inner mitochondrial membrane, which in turn pass them ...
Photosynthesis in cyanobacteria and green algae splits water into hydrogen ions and electrons. The electrons are transported ... In Chlamydomonas reinhardtii Photosystem II produces in direct conversion of sunlight 80% of the electrons that end up in the ... Competitive drainage of electrons by oxygen in algal hydrogen production.. *Economics must reach competitive price to other ...
doi:10.1007/0-387-21717-7_4. ISBN 978-0-387-00895-0. Sohn, Lydia (ed.) (1997). Mesoscopic electron transport. Springer. pp. ... Daniel C. Mattis [de] and Elliot H. Lieb, proved in 1965, that electrons could be modeled as bosonic interactions. The response ... The Luttinger liquid model, proposed by Tomonaga and reformulated by J.M. Luttinger, describes electrons in one-dimensional ... Theoretical Methods for Strongly Correlated Electrons. CRM Series in Mathematical Physics. Springer. pp. 139-186. arXiv:cond- ...
Mesoscopic Electron Transport. arXiv:cond-mat/9612126. "Proposed modular quantum computer architecture offers scalability to ... which would use electron spins in quantum dots as qubits. In 1996, during his research at IBM, he published a paper "Topics in ...
... use cyclic electron transport driven by a series of redox reactions.[5] Light-harvesting complexes surrounding ... Electron donors for anabolism[edit]. Purple bacteria also transfer electrons from external electron donors directly to ... Alastair G. McEwan (March 1994). "Photosynthetic electron transport and anaerobic metabolism in purple non-sulfur phototrophic ... "Modeling the electron transport chain of purple non-sulfur bacteria". Molecular Systems Biology. 4: 156. doi:10.1038/msb4100191 ...
... is central to its role in the electron transport chain due to the iron-sulfur clusters that can only accept one electron at a ... It is a component of the electron transport chain and participates in aerobic cellular respiration, which generates energy in ... "4 Coenzyme Q oxidation reduction reactions in mitochondrial electron transport". In Kagan, V. E.; Quinn, P. J. Coenzyme Q: ... The capacity of this molecule to act as a two-electron carrier (moving between the quinone and quinol form) and a one-electron ...
For the microbial perspective please reference the electron transport chain. Remineralization in sediments[edit]. Reactions[ ... Electron acceptor cascade[edit]. Sketch of major electron acceptors in marine sediment porewater based on idealized relative ... Boudreau, Bernard (2001). The Benthic Boundary Layer: Transport Processes and Biogeochemistry. Oxford University Press. ISBN ... Redox zonation refers to how the processes that transfer terminal electrons as a result of organic matter degradation vary ...
Jonson, M.; Girvin, S. M. (1979). "Electron-Phonon Dynamics and Transport Anomalies in Random Metal Alloys". Phys. Rev. Lett. ... Such theories of localization have been applied to transport in metallic glasses, where the mean free path of the electrons is ... Thus, if the electrical conductivity is low, the mean free path of the electrons is very short. The electrons will only be ... Duwez, Pol; Willens, R. H.; Klement, W. (1960). "Metastable Electron Compound in Ag-Ge Alloys". Journal of Applied Physics. 31 ...
See electron transport chain. 3.D.1 The H+ or Na+-translocating NADH Dehydrogenase ("complex I") family 3.D.2 The Proton- ... family 1.B.78 DUF3374 electron transport-associated porin (ETPorin) family 1.C.3 α-Hemolysin (αHL) family 1.C.4 Aerolysin ... Family 3.B.1 The Na+-transporting Carboxylic Acid Decarboxylase (NaT-DC) Family 3.C.1 The Na+ Transporting ... Family 1.D.58 The Anion Transporting Prodigiosene (Prodigiosene) Family 1.D.59 The Anion Transporting Perenosin (Perenosin) ...
Processes such as electron transport and generating ATP use proton pumps.[3] A G-protein coupled receptor is a single ... Endocytosis requires energy and is thus a form of active transport. 4. Exocytosis: Just as material can be brought into the ... The cell membrane is selectively permeable and able to regulate what enters and exits the cell, thus facilitating the transport ... The cell employs a number of transport mechanisms that involve biological membranes: 1. Passive osmosis and diffusion: Some ...
Processes such as electron transport and generating ATP use proton pumps.[4] A G-protein coupled receptor is a single ... Endocytosis requires energy and is thus a form of active transport. 4. Exocytosis: Just as material can be brought into the ... The cell membrane is selectively permeable and able to regulate what enters and exits the cell, thus facilitating the transport ... Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P (2002). "The Transport of Molecules between the Nucleus and the ...
... developing a deep understanding of electron tunneling, barrier behavior and hot-electron transport.[11] In 1960, he was the ... Mead, C. A. (1 July 1962). "Transport of Hot Electrons in Thin Gold Films". Physical Review Letters. 9 (1): 46-46. Bibcode: ... a three-terminal solid-state device based on the operating principles of electron tunnelling and hot-electron transport.[12] In ... Diorio, C.; Hasler, P.; Minch, A.; Mead, C.A. (1995). "A single-transistor silicon synapse". IEEE Transactions on Electron ...
electron transport chain. The process of oxidative phosphorylation, by which the NADH and succinate generated by the citric ... Contrast electron acceptor.. electron microscope. A type of microscope that uses a beam of electrons to create an image of a ... Contrast electron donor.. electron carrier. Any of various molecules that are capable of accepting one or two electrons from ... A form of active transport and bulk transport in which a cell transports molecules out of the cell by expelling them through an ...
Ascorbic acid and electron transport". Annals of the New York Academy of Sciences. 258: 190-200. doi:10.1111/j.1749-6632.1975. ...
Electron transport in redox enzymes. bodleian.ox.ac.uk (DPhil thesis). University of Oxford. OCLC 557413704. EThOS uk.bl.ethos. ... Oxford for research supervised by Fraser Armstrong on the electron transport in redox enzymes in 1997. Following her D.Phil., ... and for solving its structure by electron cryomicroscopy'. Publications http://www.mrc-mbu.cam.ac.uk/people/judy-hirst/ ...
2012 The Royal Society of Chemistry Barker Award Hirst, Judy (1997). Electron transport in redox enzymes. bodleian.ox.ac.uk ( ... in particular the application of dynamic electrochemical techniques in studies of complex electron-transfer and catalytic ...
He contributed to the development of electron transport theory related to semiconductors and developed a Monte Carlo method for ... 5-. ISBN 978-3-642-10571-5. Nag, B.R (2017). Electron Transport in Compound Semiconductors. Table of Contents. Springer Series ... He authored three monographs, Theory of electrical transport in semiconductors, Physics of Quantum Well Devices and Electron ... ISBN 978-0-306-47127-8. B.R. Nag (6 December 2012). Electron Transport in Compound Semiconductors. Springer Science & Business ...
In 1995 she earned her PhD with her thesis titled "Electron transport in polymer composites" at École Polytechnique Fédérale de ... "Electron transport in polymer composites". EPFL. Retrieved March 15, 2020. "Movers - Silke Bühler-Paschen, professor, Technical ... "Switching electron properties on and off individually". August 22, 2019. Retrieved March 16, 2020. "Switching electron ... She realized the individual toggling of different electronic degrees of freedom in correlated electron systems. Bühler-Paschen ...
Without ATP synthase, the electron transport chain will not produce any ATP.[1] The most common MT-ATP6 mutation found with ... though the mutations in cytochrome c oxidase and other electron transport chain proteins were not discovered until 1977.[6] ... the fourth complex in the mitochondrial electron transport chain. Though the subunits of the protein found in affected cells ... Two healthy mitochondria from mammalian lung tissue as shown by electron microscopy ...
They are transported by the blood plasma and the lymphatic system. Plasma cells originate in the bone marrow; B cells ... Their cytoplasm also contains a pale zone that on electron microscopy contains an extensive Golgi apparatus and centrioles (EM ...
Transmission electron microscope (TEM) image of a lipid vesicle. The two dark bands around the edge are the two leaflets of the ... These proteins mainly transport chemicals and information across the membrane.[3]. The membrane contains many proteins. The ...
... until it decelerates to a point where it can interact with an electron.[35] The encounter annihilates both electron and ... which has a half-life of 110 minutes and can be transported a reasonable distance before use, or to rubidium-82 (used as ... Recently rubidium-82 generators have become commercially available.[33] These contain strontium-82, which decays by electron ... The most significant fraction of electron-positron annihilations results in two 511 keV gamma photons being emitted at almost ...
... while major veins are responsible for its transport outside of the leaf. At the same time water is being transported in the ... Scanning electron microscope image of trichomes on the lower surface of a Coleus blumei (coleus) leaf ... Vascular plants transport sucrose in a special tissue called the phloem. The phloem and xylem are parallel to each other, but ... Once sugar has been synthesized, it needs to be transported to areas of active growth such as the plant shoots and roots. ...
Ryabchikova, Elena I.; Price, Barbara B. (2004). Ebola and Marburg Viruses: A View of Infection Using Electron Microscopy. ... "West Africa - Ebola virus disease Update: Travel and transport". International travel and health. World Health Organization ( ... Transport, travel, contact. Transportation crews are instructed to follow a certain isolation procedure, should anyone exhibit ... An electron microscopist from USAMRIID discovered filoviruses similar in appearance to Ebola in the tissue samples sent from ...
4.2 Phosphorylation, chaperones, and transport. *4.3 The translocon on the outer chloroplast membrane (TOC) *4.3.1 Toc34 and 33 ... Scientists have attempted to observe chloroplast replication via electron microscopy since the 1970s.[17][18] The results of ... Phosphorylation, chaperones, and transportEdit. After a chloroplast polypeptide is synthesized on a ribosome in the cytosol, ... its genes encode eleven subunits of a protein complex which mediates redox reactions to recycle electrons,[24] which is similar ...
... in which a two-dimensional electron gas with very high carrier mobility is used for charge transport, are especially suitable ... The electron mobility and hole mobility columns show the average speed that electrons and holes diffuse through the ... By controlling the number of electrons that can leave the base, the number of electrons entering the collector can be ... electrons and holes are formed at, and move away from the junction), and electrons are injected into the base region. Because ...
5 Ribosome on the rough ER 6 Proteins that are transported 7 Transport vesicle 8 Golgi apparatus 9 Cis face of the Golgi ... Porter K.R; Claude A. & Fullam E.F. (1945). "A study of tissue culture cells by electron microscopy". J Exp Med. 81 (3): 233- ... It is the transport network for molecules going to specific places, as compared to molecules that float freely in the cytoplasm ... Electron micrograph of rough endoplasmic reticulum network around the nucleus (shown in lower right-hand side of the picture). ...
The ancient Romans also had a complex system of aqueducts,[52] which were used to transport water across long distances.[52] ... For example, science might study the flow of electrons in electrical conductors by using already-existing tools and knowledge. ... The rise in technology has led to skyscrapers and broad urban areas whose inhabitants rely on motors to transport them and ... Main article: History of transport. Meanwhile, humans were learning to harness other forms of energy. The earliest known use of ...
Early diagenesis in newly formed aquatic sediments is mediated by microorganisms using different electron acceptors as part of ...
Hatefi, Y. (1985): "The mitochondrial electron transport and oxidative phosphorylation system". Ann Rev Biochem, 54:1015-1069. ...
MP and VPg interact to provide specificity for the transport of viral RNA from cell to cell. To fulfill energy requirements, MP ... using X-ray crystallography and cryo-electron microscopy. Depending on the type and degree of dehydration the viral particle is ...
An electron transport chain (ETC) is how a cell gets energy from sunlight in photosynthesis. Electron transport chains also ... Electron transport chain. A process in which a series of electron carriers operate together to transfer electrons from donors ... The electron transport chain consists of a series of redox reactions in which electrons are transferred from a donor molecule ... This is the result of the series of redox reactions.[2] What the electron transport chain does is produce this gradient.[3][4] ...
These appear electron-dense under an electron microscope and are insoluble. Viroplasms are localized in the perinuclear area or ... An aggresome is a perinuclear site where misfolded proteins are transported and stored by the cell components for their ... There are many viroplasms in one infected cell, where they appear dense to electron microscopy. Very little is understood about ... Disruption of cellular membranes can, for example, slow the transport of immunomodulatory proteins to the surface of infected ...
Electron transport chain. *Fatty acid synthetase complex. *Glycine decarboxylase complex. *Mitochondrial trifunctional protein ...
Active transport and Passive transport - Movement of molecules into and out of cells. ... transmission electron microscopy, etc. have allowed scientists to get a better idea of the structure of cells.[8] ...
for "their discoveries of machinery regulating vesicle traffic, a major transport system in our cells"[۸۱] ... "for his contributions to the theory of electron transfer reactions in chemical systems"[۳۴] ... "for his pioneering studies of electron scattering in atomic nuclei and for his thereby achieved discoveries concerning the ... "for his pioneering investigations concerning deep inelastic scattering of electrons on protons and bound neutrons, which have ...
... when it absorbs an excited electron released from compounds of the electron transport chain. Superoxide is known to denature ...
... stripped of their electron shells), and about 1% are solitary electrons (similar to beta particles). Of the nuclei, about 90% ... 2011). Australian Transport Safety Bureau. *^ https://cars.usnews.com/cars-trucks/daily-news/100317-cosmic-rays-may-be-causing- ... Hence, next to photons electrons and positrons usually dominate in air showers. These particles as well as muons can be easily ... At higher energies, up to 500 GeV, the ratio of positrons to electrons begins to fall again. The absolute flux of positrons ...
Coat-proteins, like clathrin, are used to build small vesicles in order to transport molecules within cells. The endocytosis ... "Molecular model for a complete clathrin lattice from electron cryomicroscopy". Nature. 432 (7017): 573-9. doi:10.1038/ ... allowing the clathrin to recycle while the vesicle gets transported to a variety of locations. ...
Transport[edit]. SVCTs appear to be the predominant system for vitamin C transport in the body,[102] the notable exception ... UDP-glucose 6-dehydrogenase uses the co-factor NAD+ as the electron acceptor. The transferase UDP-glucuronate pyrophosphorylase ... Ascorbic acid is absorbed in the body by both active transport and simple diffusion. Sodium-Dependent Active Transport-Sodium- ... Wilson JX (2005). "Regulation of vitamin C transport". Annual Review of Nutrition. 25: 105-125. doi:10.1146/annurev.nutr. ...
... these nanowires can transport electrons up to centimetre-scale distances.[13] Long-range electron transfer via pili networks ... Nanowires may function as conduits for electron transport between different members of a microbial community.[10] ... In microbial fuel cells (MFCs), bacterial nanowires generate electricity via extracellular electron transport to the MFC's ... Species of the genus Geobacter use nanowires to transfer electrons to extracellular electron acceptors (such as Fe(III) oxides ...
... one electron donor and one electron acceptor. When a photon is converted into an electron hole pair, typically in the donor ... European Commission, Joint Research Centre, Institute for Energy and Transport. *^ PV production grows despite a crisis-driven ... Electrons are excited from their current molecular/atomic orbital. Once excited an electron can either dissipate the energy as ... The absorption of light, generating either electron-hole pairs or excitons.. *The separation of charge carriers of opposite ...
Studies of electron heating in PFRC-2 reached 500 eV with pulse lengths of 300 ms.[11] ... National Transport Code Collaboration (NTCC) Modules Library. See alsoEdit. *Project Sherwood ...
Nitrogen-doped carbon nanotube structure tailoring and time-resolved transport measurements in a transmission electron ... G. Dmitri, Y. Bando : «Electron Microscopy of Boron Nitride Nanotubes» Electron Microscopy of Nanotubes (2003) ... In situ growth of Indium nanocrystals on InP nanorods mediated by electron beam of transmission electron microscope» Chem. Phys ... Electron-beam irradiation induced conductivity in ZnS nanowires as revealed by in situ transmission electron microscope» J. ...
Plants also reduce transport through plasmodesmata in response to injury. The discovery of plant viruses causing disease is ... Viruses are extremely small and can only be observed under an electron microscope. The structure of a virus is given by its ... Plants have specialized mechanisms for transporting mRNAs through plasmodesmata, and these mechanisms are thought to be used by ... therefore transport through plasmodesmata is the preferred path for virions to move between plant cells. ...
"Trap-related carrier transports in p-channel field effect transistor with polycrystallin Si/HSiON gate stack", Japanese Journal ... Electron-beam-induced current (EBIC) is a semiconductor analysis technique performed in a scanning electron microscope (SEM) or ... In EBIC, energetic electrons take the role of the photons, causing the EBIC current to flow. However, because the electron beam ... W. S. Lau, D. S. H. Chan, J. C. H. Phang, K. W. Chow, K. S. Pey, Y. P. Lim and B. Cronquist, "True oxide electron beam induced ...
Cations are reduced (electrons are added) at the cathode, while metal atoms are oxidized (electrons are removed) at the anode.[ ... Important reasons for this high rate of growth of the electric battery industry include the electrification of transport,[78] ... Batteries are designed so that the energetically favorable redox reaction can occur only when electrons move through the ... "liquid electrolytes to transport lithium ions between the anode and the cathode. If a battery cell is charged too quickly, it ...
Electron transport chains in bacteria Facultative anaerobes are organisms able to grow in the presence or absence of molecular ... Simon J. (2018) Electron Transport in Facultative Anaerobes. In: Roberts G., Watts A., European Biophysical Societies (eds) ... Figure 1 depicts the corresponding electron transport network from the facultatively anaerobic bacterium Escherichia coli. ... In anaerobic respiration a variety of alternative terminal electron acceptors can be used by facultative anaerobes. Prominent ...
The electron transport chain is comprised of a series of enzymatic reactions within the inner membrane of the mitochondria, ... Electrons move through the electron transport chain from a higher to lower energy state. Energy release moves protons through ... uncouple the electron transport chain in order to dissipate the energy as heat. This is accomplished through a transport ... The electron transport chain is comprised of a series of enzymatic reactions within the inner membrane of the mitochondria, ...
This free synopsis covers all the crucial plot points of Oxidative Phosphorylation and Electron Transport. ... These electrons then pass through a series of four protein complexes called the electron transport chain. The energy produced ... Next, we will discuss electron flow through the electron transport chain and ATP synthesis through oxidative phosphorylation. ... Home → SparkNotes → Biology Study Guides → Oxidative Phosphorylation and Electron Transport → Introduction. Oxidative ...
Sorbello R.S. (1982) Macroscopic and microscopic fields in electron and atom transport. In: Burridge R., Childress S., ...
The electron transport chain is a chemical reaction where electrons are transferred from a high-energy molecule to a low-energy ... The electron transport chain is a chemical reaction where electrons are transferred from a high-energy molecule to a low-energy ... Why Do Some Atoms Gain or Lose Electrons to Form Ions?. A: Atoms gain or lose electrons based on their respective electron ... The electron transport chain is critical to the production of adenosine triphosphate, or ATP, which is a source of energy for ...
... photosynthetic electron transport and phosphorylation. [Achim Trebst; Mordhay Avron; R S Alberte; et al] ... Noncyclic Electron Transport.- IV. Cyclic Electron Transport.- V. Pseudocyclic Electron Transport.- VI. Regulation of Electron ... Relation of Electron Transport to Phosphorylation.- I. Electron Transport Patterns.- II. Coupling Between Electron Transport ... Electron Transport.- 1. General 1 a. Physical Aspects of Light Harvesting, Electron Transport and Electrochemical Potential ...
title = {Electron thermal transport in tokamak plasmas}. author = {Konings, J A}. abstractNote = {The process of fusion of ... Konings, J A. Electron thermal transport in tokamak plasmas. Netherlands: N. p., 1994. Web. ... This `anomalous transport` of thermal energy implies that, to reach the condition for nuclear fusion, a fusion reactor must ... This `anomalous transport` of thermal energy implies that, to reach the condition for nuclear fusion, a fusion reactor must ...
the electron momentum, the electron group velocity given by. , where is the energy, the absolute value of electron charge, the ... B. K. Blotekjaer, "Transport equations for electrons in two-valley semiconductors," IEEE Transactions on Electron Devices, vol ... is the effective electron mass which in silicon is with the electron mass and the reduced Plancks constant is taken as for ... 300 K) and the electron temperature as (resp. ) with in the case of partial thermal equilibrium. ...
One such essential process is electron transport, which powers all life forms by shuttling electrons between key protein ... "Powering off TB: New electron transport gene is a potential drug target ." Medical News Today. MediLexicon, Intl., 13 Aug. 2015 ... 2015, August 13). "Powering off TB: New electron transport gene is a potential drug target ." Medical News Today. Retrieved ... Powering off TB: New electron transport gene is a potential drug target ...
Bacterial extracellular electron transport (EET) to solid electron acceptors, such as Fe(III)- and Mn(IV)-oxide minerals and ... A cell-surface decaheme cytochrome involved in respiratory electron transport to extracellular electron acceptors. J Biol Inorg ... where k0 is a standard rate constant, n is the number of electrons, α is an electron transfer coefficient, and ΔE is the ... Rate enhancement of bacterial extracellular electron transport involves bound flavin semiquinones Message Subject (Your Name) ...
Electron transport is the last stage of cell respiration. The chain passes high-energy electrons... ... The electron transport chain takes place in the membranes of the mitochondria in eukaryotic cells. ... The electron transport chain takes place in the membranes of the mitochondria in eukaryotic cells. Electron transport is the ... Rotenone is in the class of electron transport inhibitors, which bind at some point on the transport chain, keeping electrons ...
Electron Transport Chain Is Biochemically Linked to Pilus Assembly Required for Polymicrobial Interactions and Biofilm ... Adjustments to Photosystem Stoichiometry and Electron Transfer Proteins Are Key to the Remarkably Fast Growth of the ...
Electron Transport Chain Deficiencies: Mitochondrial Related Articles. Groundbreaking Discovery: Animal Cells Powered by ... 2 Abstracts with Electron Transport Chain Deficiencies: Mitochondrial Research. Filter by Study Type. Animal Study. ... Diseases : Electron Transport Chain Deficiencies: Mitochondrial, Metabolic Syndrome X, Mitochondrial Dysfunction Problem ... 1 Substances Researched for Electron Transport Chain Deficiencies: Mitochondrial Name. AC. CK. Focus. ...
Make research projects and school reports about electron-transport chain easy with credible articles from our FREE, online ... and pictures about electron-transport chain at Encyclopedia.com. ... electron-transport chain A Dictionary of Plant Sciences © A ... electron-transport chain (respiratory chain) A system of electron carriers, present in mitochondria and the cell membranes of ... electron-transport chain 1. Respiratory chain. A system of redox compounds called electron carriers, present in mitochondria, ...
multistep electron hopping. It is widely accepted that electron transport can occur over molecular-scale distances in ... 23), which attributes long-range electron transport through Geobacter biofilms not to multistep electron hopping but to an ... the presence of redox gradient that drives electron transport through the biofilm to electrode 1 when such electron transport ... of biofilm electron transport to an anode coupled to acetate oxidation with measurements of biofilm electron transport between ...
Published Article: Biological electron transport goes the extra mile. This content will become publicly available on November ...
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... transport MC) and presents some physical problems related to the transport of hot electrons in solid targets using transport MC ... Transport of Energetic Electrons in Solids. Book Subtitle. Computer Simulation with Applications to Materials Analysis and ... Transport of Energetic Electrons in Solids. Computer Simulation with Applications to Materials Analysis and Characterization. ... This book focusses on the study of the electron-solid interaction ( ...
... and their values are consistent with the picture that the electron transport is mainly induced by the short wavelength ... Correlation between electron heat diffusivity and short wavelength (kri {approximately} 5) fluctuation amplitude was observed ... Wong, K.L.; Itoh, K.; Itoh, S.-I.; Fukuyama, A. & Yagi, M. Short Wavelength Fluctuations and Electron Transport in TFTR, report ... and their values are consistent with the picture that the electron transport is mainly induced by the short wavelength ...
Electron transport chains are redox reactions that transfer electrons from an electron donor to an electron acceptor. The ... An electron transport chain (ETC) couples a chemical reaction between an electron donor (such as NADH) and an electron acceptor ... The mitochondrial electron transport chain removes electrons from an electron donor (NADH or QH2) and passes them to a terminal ... Electrons may enter an electron transport chain at the level of a mobile cytochrome or quinone carrier. For example, electrons ...
... oxygen enters the respiration pathway as the electron acceptor at the end of the electron transport chain. ... oxygen enters the respiration pathway as the electron acceptor at the end of the electron transport chain. ... The transport chain often is likened to a series of magnets, each stronger than the last, which pull electrons from one weaker ... The oxidation takes place in a series of steps, like the electron chain of photosynthesis, but with different transport ...
Electrons flow through the electron transport chain to molecular oxygen; during this flow, protons are moved across the inner ... mobile electron transport protein, cytochrome c. Cytochrome c transfers its electrons to the final electron transport component ... Electrons flow through the electron transport chain to molecular oxygen; during this flow, protons are moved across the inner ... accepts electrons from NADH. The NADH releases a proton and two electrons. The electrons flow through a flavoprotein containing ...
From there, the electrons are transferred to the mobile electron carrier cytochrome c (cyt c). Cyt c delivers the electrons to ... Generally, molecules of the electron transport chain are organized into four complexes (I-IV). The molecules pass electrons to ... Both NADH and FADH2 transfer electrons to ubiquinone, a mobile electron carrier that passes the electrons to complex III. ... The electron transport chain is a set of proteins and other organic molecules found in the inner membrane of mitochondria in ...
The electron carriers are at successively lower energy levels hence, as the electron moves on from one carrier to the next some ... Each hydrogen atom is split into its constituent H+ (hydrogen ion) and electron. The electron is the part that actually gets ... Oxygen acts as the final electron acceptor in the chain, so the oxygen, electrons and hydrogen ions together form water. ... Electron Transport Chain / Oxidative Phosphorylation. Production of ATP using NADH and FADH. ...
Explain the operation of the electron transport chain in the development ATP and find homework help for other Science ... The electron transport chain, as the name suggests, is a series of passing on electrons to atoms or molecules that are more ... The electron transport chain, as the name suggests, is a series of passing on electrons to atoms or molecules that are more ... Explain how the electron transport chain (and ATP-synthase) works. Please include the inputs and... ...
Transport coefficients and electron interaction strength. Author(s). Levitov, Leonid; Abanin, Dmitry A.; Skachko, I.; Du, X.; ... "Fractional quantum Hall effect in suspended graphene: Transport coefficients and electron interaction strength." Physical ... on which only two-terminal transport measurements could be performed. Here we address the problem of extracting transport ... The gap is found to be significantly larger than in GaAs-based structures, signaling much stronger electron interactions in ...
We report here on detailed electron beam transport for an LPA electron beam on the COXINEL test line, that consists of strong ... After describing the measured LPA characteristics, we show that we can properly transport the electron beam along the line, ... We then study the sensitivity of the transport to the electron beam pointing and skewed quadrupolar components. ... We also illustrate the influence of the chromatic effects induced by the electron beam energy spread, both experimentally and ...
... electrons from inorganic electron donors (nitrite, ferrous iron, electron transport chain.) enter the electron transport chain ... The electron transport chain (ETC) is a series of protein complexes that transfer electrons from electron donors to electron ... The electron transport chain is built up of peptides, enzymes, and other molecules. The flow of electrons through the electron ... The electron transport chain comprises an enzymatic series of electron donors and acceptors. Each electron donor will pass ...
The overall electron chain transport reaction is: 2H+ + 2e+ + 1/2O2 ---, H2O + energy. This reaction actually involves eight or ... Here a series of reactions occurs in which electrons are transported to meet up with oxygen from respiration. ... Every use of the electron transport chain results in the production of three ATP molecules. - Stock Image C027/8502 ... A series of redux reactions moves electrons from a donor (NADH or QH2) to an acceptor (O2). A proton gradient is created across ...
  • The electron transport chain is comprised of a series of enzymatic reactions within the inner membrane of the mitochondria, which are cell organelles that release and store energy for all physiological needs. (news-medical.net)
  • Although electron transport chains and mitochondria are characteristic of eukaryotic cells, some bacteria and Archaea have similar features. (reference.com)
  • The electron transport chain takes place in the membranes of the mitochondria in eukaryotic cells. (reference.com)
  • A system of redox compounds called electron carriers, present in mitochondria , which sequentially transport electrons and/or protons previously removed from metabolites in glycolysis , the citric-acid cycle , and other metabolic reactions. (encyclopedia.com)
  • While some bacteria have electron transport chains similar to those in chloroplasts or mitochondria, other bacteria use different electron donors and acceptors. (thefullwiki.org)
  • Illustration of the electron transport chain, a series of protein complexes located in the inner membrane of mitochondria. (sciencephoto.com)
  • The electron transport system creates an electron gradient inside the mitochondria along the inner membrane so that when protons re-enter the matrix through the ATP synthase, their potential energy is converted into chemical energy in the form of ATP. (brightstorm.com)
  • Measurements of ubiquinone redox poise in isolated mitochondria suggested that SA blocked electron flow from the substrate dehydrogenases to the ubiquinone pool. (plantphysiol.org)
  • The electron transport chain ( ETC ) is located in the inner membrane of the mitochondria . (nodak.edu)
  • The PPR40 protein is localized in the mitochondria and found in association with Complex III of the electron transport system. (plantphysiol.org)
  • GOT1 normally consumes aspartate to transfer electrons into mitochondria, but, upon ETC inhibition, it reverses to generate aspartate in the cytosol, which partially compensates for the loss of mitochondrial aspartate synthesis. (nih.gov)
  • In contrast, an analogous ETC module from mitochondria could not function in electron transfer to nitrogenase. (jic.ac.uk)
  • It is concluded that the cytostatic inhibitory effects of mycothiazole on mitochondrial electron transport function in sensitive cell lines may depend on a pre-activation step that is absent in insensitive cell lines with intact mitochondria, and that a second lower-affinity cytotoxic target may also be involved in the metabolic and growth inhibition of cells. (mdpi.com)
  • Direct supplementation of CL to isolated mitochondria not only rescues the PINK1- induced complex I defects but also rescues the inefficient electron transfer between complex I and ubiquinone in specific mutants. (rupress.org)
  • Oxygen molecules are required for the removal of electrons from the electron transport chain in the mitochondria. (thefreedictionary.com)
  • Singh, N., Hroudová, J. and Fisar, Z. (2015) Cannabinoid-Induced Changes in the Activity of Electron Transport Chain Complexes of Brain Mitochondria. (scirp.org)
  • The improved survival was not a direct consequence of the absence of electron transport, but rather was attributable to the large amounts of NADH which accumulate in the mitochondria of chemically hypoxic or respiration-deficient cells. (aspetjournals.org)
  • In anaerobic respiration a variety of alternative terminal electron acceptors can be used by facultative anaerobes. (springer.com)
  • Bacterial extracellular electron transport (EET) to solid electron acceptors, such as Fe(III)- and Mn(IV)-oxide minerals and artificial electrodes, represents a central driving force for geochemical mineral cycling and bioelectrical systems ( 1 ⇓ - 3 ). (pnas.org)
  • MR-1 expresses a significant quantity of cell-surface redox-active proteins, namely the c- type cytochromes ( c- Cyts), which form a hypothetical protein complex "OmcA-MtrCAB" ( 6 , 7 ) in which these proteins work together to transport electrons generated by the intracellular metabolic oxidation of organic matter to solid extracellular electron acceptors as a terminal process in microbial respiration ( 8 ⇓ - 10 ). (pnas.org)
  • that can use electron acceptors residing outside the cell for respiration ( 3 ). (pnas.org)
  • The electron transport chain (ETC) is a series of protein complexes that transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couples this electron transfer with the transfer of protons (H+ ions) across a membrane. (wikipedia.org)
  • In anaerobic respiration, other electron acceptors are used, such as sulfate. (wikipedia.org)
  • The electron transport chain comprises an enzymatic series of electron donors and acceptors. (wikipedia.org)
  • Accordingly, the inhibition by the other compounds seemingly interfering at the same site as well as that by electron acceptors could be due to interference at a different redox step in desaturation. (biomedsearch.com)
  • In vitro these compounds function also as electron acceptors in diaphorase reactions catalyzed by ferredoxin:NADP oxidoreductase. (biomedsearch.com)
  • Here we present LMD simulations of charge transfer between a pair of fullerene molecules, which commonly serve as electron acceptors in OSCs. (rsc.org)
  • Here we have applied variable fluorescence measurements and EPR spectroscopy to probe the status of the quinone acceptors, the Mn cluster and other electron transfer components in PS II with controlled levels of protein phosphorylation. (lu.se)
  • Arrange the following electron acceptors in the proper order in which they participate in electron transport. (mhhe.com)
  • According to Reference.com, in an electron transport chain, the high-energy molecule that gives up the election is called the donor, while the low-energy molecule that is getting the electron is called the acceptor. (reference.com)
  • These electrons are passed from the donor molecule to the acceptor oxygen molecule through a membrane, creating hydrogen ions that are used in ATP. (reference.com)
  • Oxygen is used as an electron acceptor within the electron transport chain of aerobic respiration to generate adenosine triphosphate, or ATP. (reference.com)
  • An electron transport chain (ETC) couples a chemical reaction between an electron donor (such as NADH ) and an electron acceptor (such as O 2 ) to the transfer of H + ions across a membrane , through a set of mediating biochemical reactions. (thefullwiki.org)
  • Redox reactions are chemical reactions in which electrons are transferred from a donor molecule to an acceptor molecule. (thefullwiki.org)
  • The transfer of electrons from a high-energy molecule (the donor) to a lower-energy molecule (the acceptor) can be spatially separated into a series of intermediate redox reactions. (thefullwiki.org)
  • After the Krebs cycle is completed, oxygen enters the respiration pathway as the electron acceptor at the end of the electron transport chain. (cliffsnotes.com)
  • The last acceptor in the line is oxygen, an atom of which accepts two energy‐depleted electrons and two hydrogen ions (protons) and forms a molecule of water. (cliffsnotes.com)
  • Oxygen acts as the final electron acceptor in the chain, so the oxygen, electrons and hydrogen ions together form water. (s-cool.co.uk)
  • In aerobic respiration, the flow of electrons terminates with molecular oxygen being the final electron acceptor. (wikipedia.org)
  • Each electron donor will pass electrons to a more electronegative acceptor, which in turn donates these electrons to another acceptor, a process that continues down the series until electrons are passed to oxygen, the most electronegative and terminal electron acceptor in the chain. (wikipedia.org)
  • Passage of electrons between donor and acceptor releases energy, which is used to generate a proton gradient across the mitochondrial membrane by "pumping" protons into the intermembrane space, producing a thermodynamic state that has the potential to do work. (wikipedia.org)
  • A series of redux reactions moves electrons from a donor (NADH or QH2) to an acceptor (O2). (sciencephoto.com)
  • Unlike POR, OOR was unable to use a previously identified flavodoxin (FldA) as an electron acceptor. (asm.org)
  • The in vivo electron acceptor of this enzyme is likely to be an endogenous flavodoxin, which was partially purified and shown to be reduced by POR. (asm.org)
  • This decreased electron transfer may induce the over-reduction of the plastoquinone pool and consequently the appearance of acceptor side photoinhibition in PSII even at low light intensities. (frontiersin.org)
  • Current production of the Aro-5 strain, with a graphite anode serving as the electron acceptor, was less than 10% of that of the control strain. (asm.org)
  • It is concluded that this technique can be used to study the functional organization of the anaerobic proton-translocating electron-transport chains that use nitrate or fumarate as terminal electron acceptor. (portlandpress.com)
  • We study here several simple models of the electron transfer (ET) in a one-dimensional nonlinear lattice between a donor and an acceptor and propose a new fast mechanism of electron surfing on soliton-like excitations along the lattice. (ucm.es)
  • In a heated system, the electron transfer between a donor and an acceptor is modeled as a diffusion-like process. (ucm.es)
  • Electron transport chains are redox reactions that transfer electrons from an electron donor to an electron acceptor. (powershow.com)
  • The redox reaction is simultaneously coupled to the transport of PROTONS across the inner mitochondrial membrane. (nih.gov)
  • In eukaryotes, the electron transport chain is located in the inner mitochondrial membrane. (news-medical.net)
  • The reactions of the electron transport chain involve several large membrane protein complexes within the inner mitochondrial membrane. (news-medical.net)
  • In eukaryotic organisms the electron transport chain, and site of oxidative phosphorylation, is found on the inner mitochondrial membrane. (wikipedia.org)
  • The energy stored from the process of respiration in reduced compounds (such as NADH and FADH) is used by the electron transport chain to pump protons into the intermembrane space, generating the electrochemical gradient over the inner mitochondrial membrane. (wikipedia.org)
  • At the inner mitochondrial membrane, electrons from NADH and FADH2 pass through the electron transport chain to oxygen, which is reduced to water. (wikipedia.org)
  • Energy obtained through the transfer of electrons down the electron transport chain is used to pump protons from the mitochondrial matrix into the intermembrane space, creating an electrochemical proton gradient (ΔpH) across the inner mitochondrial membrane. (wikipedia.org)
  • a group of specific carrier molecules in the inner mitochondrial membrane that transfer electrons from hydrogen to oxygen. (thefreedictionary.com)
  • It is the terminal oxidase complex of the RESPIRATORY CHAIN and collects electrons that are transferred from the reduced CYTOCHROME C GROUP and donates them to molecular OXYGEN, which is then reduced to water. (nih.gov)
  • Cytochrome c oxidase is the last step in the electron transport chain. (news-medical.net)
  • It accepts two electrons from two cytochrome c molecules and passes them four at a time to oxygen. (news-medical.net)
  • Electrons flow from succinate to FAD (the flavin‐adenine dinucleotide) coenzyme, through an iron‐sulfur protein and a cytochrome b 550 protein (the number refers to the wavelength where the protein absorbs), and to coenzyme Q. No protons are translocated by Complex II. (cliffsnotes.com)
  • It accepts electrons from reduced coenzyme Q, moves them within the complex through two cytochromes b, an iron‐sulfur protein, and cytochrome c 1 . (cliffsnotes.com)
  • Complex III transfers its electrons to the heme group of a small, mobile electron transport protein, cytochrome c . (cliffsnotes.com)
  • Cytochrome c transfers its electrons to the final electron transport component, Complex IV , or cytochrome oxidase . (cliffsnotes.com)
  • Cytochrome oxidase transfers electrons through a copper‐containing protein, cytochrome a, and cytochrome a 3 , and finally to molecular oxygen. (cliffsnotes.com)
  • The light-driven reactions take place in the thylakoid membranes and three major membrane-intrinsic protein complexes carry out photosynthetic electron transfer, photosystem II, the cytochrome bf complex and photosystem I. To elucidate photosynthetic electron transport in oxygenic photosynthesis site-directed mutagenesis and biophysical techniques were employed in cyanobacteria which have the advantage over plants that they are easily genetically manipulated. (illinois.edu)
  • This work focused on electron transfer linking the cytochrome bf complex and photosystem I, characterization of the plastoquinol oxidation site of the cytochrome bf complex and electron transfer within the PsaC polypeptide of the photosystem I complex. (illinois.edu)
  • This inhibition could not be reversed by adding chemicals that donate electrons to photosystem I, indicating that carriers past the cytochrome b/f complex were not involved. (biomedsearch.com)
  • Energy for thermogenesis is provided by an increase in mitochondrial electron transport through the alternative oxidase (Aox), which diverts electron transport from the cytochrome pathway and uncouples ATP production ( Meeuse, 1975 ). (plantphysiol.org)
  • Changes to the balance between electron transport and ATP synthesis negatively affect photosynthesis and ultimately the plant's growth, as observed for example in tobacco cytochrome b6f complex loss-of-function mutants. (edu.au)
  • In the ppr40-1 mutant the electron transport through Complex III is strongly reduced, whereas Complex IV is functional, indicating that PPR40 is important for the ubiqinol-cytochrome c oxidoreductase activity of Complex III. (plantphysiol.org)
  • Depending on the substrate, electrons are transported from Complex I (NADH dehydrogenase) and Complex II (succinate dehydrogenase) through ubiquinon and Complex III (cytochrome c reductase) to cytochrome c and to Complex IV (cytochrome c oxidase [COX]), which produces water. (plantphysiol.org)
  • The results of this work suggest that iron deficiency induces partial blocking of the electron transfer between PSII and PSI, due to a lower concentration of the electron donor cytochrome c 6 . (frontiersin.org)
  • As electrons are passed through the chain by a series of oxidation-reduction reactions, energy is released, creating a gradient of hydrogen ions, or protons, across the membrane. (news-medical.net)
  • Four protons are thus transported across the membrane in the reaction. (news-medical.net)
  • Complex II operates parallel to Complex I. However, no protons are transported into the intermembrane space. (news-medical.net)
  • This is accomplished through a transport protein that moves protons down the electrochemical gradient, bypassing ATP synthase. (news-medical.net)
  • As electrons are pulled from NADH and FADH 2 , protons (H + ) also are released, and the protein complexes pump them into the intermembrane space. (cliffsnotes.com)
  • Because those enzymes do not pump protons, we were able to split electron transport and proton pumping (ATP synthesis) and inquire which of the metabolic deficiencies associated with the loss of oxidative phosphorylation should be attributed to each of the 2 processes. (nih.gov)
  • an atom or molecule that does not have the same number of electrons as it has protons. (asu.edu)
  • Hydrogen ions (protons) are transported across the membrane. (thefreedictionary.com)
  • The source of the protons and electrons is primarily nicotinamide adenine dinucleotide, which is recycled during the reaction. (thefreedictionary.com)
  • I think that the protons on one side of the membrane pair with electrons on the other (or inside the double membrane) forming quasi-particle pairs which then form quantum condensate (Bose-Einstein condensate) acting like one global particle with a much higher energy at its disposal. (blogspot.com)
  • The transfer of electrons is coupled to the translocation of protons across a membrane, producing a proton gradient. (powershow.com)
  • Now that we have discussed the events of glycolysis and the citric acid cycle , we are ready to explore the electron transport chain and oxidative phosphorylation, the last step in cellular respiration. (sparknotes.com)
  • The energy produced from the flow of electrons drives oxidative phosphorylation in which ATP is synthesized via the addition of phosphor (phosphorylation) to ADP. (sparknotes.com)
  • Next, we will discuss electron flow through the electron transport chain and ATP synthesis through oxidative phosphorylation . (sparknotes.com)
  • The electron transport chain in the mitochondrion is the site of oxidative phosphorylation in eukaryotes . (thefullwiki.org)
  • In bacteria, the electron transport chain can vary over species but it always constitutes a set of redox reactions that are coupled to the synthesis of ATP, through the generation of an electrochemical gradient, and oxidative phosphorylation through ATP synthase. (wikipedia.org)
  • This entire process is called oxidative phosphorylation since ADP is phosphorylated to ATP by using the electrochemical gradient established by the redox reactions of the electron transport chain. (wikipedia.org)
  • The electron transport system is the stage in cellular respiration in which oxidative phosphorylation occurs and the bulk of the ATP is produced. (brightstorm.com)
  • The last step of aerobic respiration is known alternately as electron transport system or as oxidative phosphorylation. (brightstorm.com)
  • They're also the place where the process of oxidative phosphorylation occurs to produce ATP, using the complexes on the electron transport chain. (hstalks.com)
  • Physical Aspects of Light Harvesting, Electron Transport and Electrochemical Potential Generation in Photosynthesis of Green Plants. (worldcat.org)
  • 2. A system of redox compounds involved in electron transport in metabolic pathways such as photosynthesis . (encyclopedia.com)
  • Electron transport chains are used for extracting energy from sunlight ( photosynthesis ) and from redox reactions such as the oxidation of sugars ( respiration ). (thefullwiki.org)
  • The oxidation takes place in a series of steps, like the electron chain of photosynthesis, but with different transport molecules. (cliffsnotes.com)
  • As the presence of heavy metals inhibits the electron transport chain in photosynthesis, hence increases the fluorescence emission as an alternative channel to drain the energy collected from the sun. (thefreedictionary.com)
  • The reactions of the electron transport chain are carried out by a series of membrane proteins and organic molecules. (news-medical.net)
  • Here we show that flavin molecules secreted by Shewanella oneidensis MR-1 enhance the ability of its outer-membrane c -type cytochromes (OM c- Cyts) to transport electrons as redox cofactors, but not free-form flavins. (pnas.org)
  • The gradient can be used to transport molecules across membranes. (thefullwiki.org)
  • The electron transport chain, as the name suggests, is a series of passing on electrons to atoms or molecules that are more electronegative, with oxygen ultimately being the most electronegative participant. (enotes.com)
  • Carbon monoxide molecules bring the electron transport chain in a mitochondrian to a stop by. (enotes.com)
  • The electron transport chain is built up of peptides, enzymes, and other molecules. (wikipedia.org)
  • Every use of the electron transport chain results in the production of three ATP molecules. (sciencephoto.com)
  • Water molecules are broken down to release electrons. (asu.edu)
  • The electron transport chain is a series of molecules that accept or donate electrons easily. (asu.edu)
  • My research interests are mainly focused on theoretical study and simulation of electron transport and magnetism in atomic-scale nanostructures such as atomic or molecular nanojunctions, single (magnetic) ad-atoms or molecules deposited on various substrates, and so on. (cea.fr)
  • Achieving fully spin-polarized electron currents across a special class of molecules bridging two ferromagnetic electrodes. (cea.fr)
  • NADPH is used as an electron donor for carbon fixation . (thefullwiki.org)
  • The process starts with an electron donor, such as NAD+, which will combine readily with a hydrogen atom to become NADH. (enotes.com)
  • NADH is the electron donor for the ETC. (nodak.edu)
  • Although the purified enzymes were unable to reduce NAD(P), electrons from both pyruvate and 2-oxoglutarate could reduce NADP in cell extracts, consistent with a role for these oxidoreductases in the provision of NADPH as a respiratory electron donor. (asm.org)
  • What is the Electron Transport Chain? (news-medical.net)
  • Schematic representation of the electron transfer chain via chemiosmotic reactions. (news-medical.net)
  • Electrons move through the electron transport chain from a higher to lower energy state. (news-medical.net)
  • Some specialized fat cells, known as brown fat, uncouple the electron transport chain in order to dissipate the energy as heat. (news-medical.net)
  • These electrons then pass through a series of four protein complexes called the electron transport chain. (sparknotes.com)
  • The electron transport chain is a chemical reaction where electrons are transferred from a high-energy molecule to a low-energy molecule. (reference.com)
  • The electron transport chain is critical to the production of adenosine triphosphate, or ATP, which is a source of energy for living things. (reference.com)
  • The electron transfer (ET) chain from the inner to outer membrane (OM) is called the metal reduction (Mtr) pathway and is responsible for both metal-oxide reduction reactions and anodic current production in microbial fuel cells (MFCs) ( 5 , 9 ). (pnas.org)
  • Where does the electron transport chain take place? (reference.com)
  • The chain passes high-energy electrons formed during glycolysis into oxygen-creating adenosine triphosphate (ATP) for energy. (reference.com)
  • The third phase, electron transport, moves the high-energy electrons through a chain of redox reactions in the mitochondrial membrane to create ATP. (reference.com)
  • Rotenone is in the class of electron transport inhibitors, which bind at some point on the transport chain, keeping electrons from moving. (reference.com)
  • Photosynthetic electron transport chain of the thylakoid membrane. (thefullwiki.org)
  • The electron transport chain is also called the ETC . An enzyme called ATP synthase catalyzes a reaction to generate ATP. (thefullwiki.org)
  • The function of the electron transport chain is to produce this gradient [ 2 ] [ nb 2 ] . (thefullwiki.org)
  • This is an electron transport chain. (thefullwiki.org)
  • The transport chain often is likened to a series of magnets, each stronger than the last, which pull electrons from one weaker carrier and release it to the next stronger one. (cliffsnotes.com)
  • Energy from the transport chain establishes a proton gradient across the inner membrane of the mitochondrion and supplies the energy for the embedded protein complexes-which also are proton pumps and sites of the chemiosmotic process. (cliffsnotes.com)
  • The electron is the part that actually gets passed down the chain from carrier to carrier. (s-cool.co.uk)
  • Explain how the electron transport chain (and ATP-synthase) works. (enotes.com)
  • How does the electron transport chain (and ATP-synthase) work, including the inputs and final. (enotes.com)
  • The flow of electrons through the electron transport chain is an exergonic process. (wikipedia.org)
  • In the electron transport chain, the redox reactions are driven by the Gibbs free energy state of the components. (wikipedia.org)
  • The complexes in the electron transport chain harvest the energy of the redox reactions that occur when transferring electrons from a low redox potential to a higher redox potential, creating an electrochemical gradient. (wikipedia.org)
  • In photosynthetic eukaryotes, the electron transport chain is found on the thylakoid membrane. (wikipedia.org)
  • Here, light energy drives the reduction of components of the electron transport chain and therefore causes subsequent synthesis of ATP. (wikipedia.org)
  • colored green, blue and red) of each monomeric unit have a direct role in the passage of electrons in the respiratory chain. (proteopedia.org)
  • The following images attempt to illustrate how the electron transport chain (ETC) creates a proton gradient that powers the synthesis of ATP. (nodak.edu)
  • HskA showed a strong influence on the composition of the electron transport chain. (wiley.com)
  • Model of the P. putida electron transport chain inferred from the genes present in strain KT2440 genome. (wiley.com)
  • Today we will talk about a nuclear control of the electron transport chain gene expression. (hstalks.com)
  • The talk outline will be a summary of an introduction, followed by a summary of the subunits involved in the electron transport chain, and the transcription of the electron transport chain subunits. (hstalks.com)
  • There are five complexes that make up the electron transport chain, and these complexes are encoded by both nuclear and mitochondrial genomes. (hstalks.com)
  • They go through the first special protein (the photosystem II protein) and down the electron transport chain. (asu.edu)
  • Photosystem I and II don't align with the route electrons take through the transport chain because they weren't discovered in that order. (asu.edu)
  • Later, photosystem II was discovered and found to be earlier in the electron transport chain. (asu.edu)
  • When hydrogen ions move through the protein and down the electron transport chain, ATP is created. (asu.edu)
  • Electrons from the NADPH and FADH 2 are transferred to O 2 via the electron transport chain generating the energy carrier ATP and oxidized NADP + and FAD + ( Siedow and Day, 2000 ). (plantphysiol.org)
  • The mitochondrial electron transport chain (ETC) enables many metabolic processes, but why its inhibition suppresses cell proliferation is unclear. (nih.gov)
  • NDUFA4 is a subunit of complex IV of the mammalian electron transport chain. (wikipathways.org)
  • Mycothiazole, a polyketide metabolite isolated from the marine sponge Cacospongia mycofijiensis , is a potent inhibitor of metabolic activity and mitochondrial electron transport chain complex I in sensitive cells, but other cells are relatively insensitive to the drug. (mdpi.com)
  • the enzyme may act as part of the mitochondrial electron transport chain by transferring electrons to ubiquinone and acting as an uncoupling mechanism susceptible to proton leak (Miwa et al. (thefreedictionary.com)
  • This is a complex multi-step process that occurs along the electron transport chain , which serves as a "power line" through which chemical energy is released and transferred into ATP. (thefreedictionary.com)
  • Some medications can directly affect electron transport chain complexes or damage electron transport chain components. (thefreedictionary.com)
  • The flux through the electron transport chain is relevant to the aging process because it is related to the rate of production of ROS. (thefreedictionary.com)
  • We do not fully understand the reasons behind these differences between the two photosystems, but they seem to be related to differences in the manner the antennas are coupled to the reaction centers, and also to characteristics and organization of the electron transport chain downhill of the charge separation at PSI. (thefreedictionary.com)
  • The mitochondrial electron transport chain (7) consists of five enzyme complexes. (thefreedictionary.com)
  • The electron transport chain is involved in mitochondrial energy production," says Johnson. (thefreedictionary.com)
  • The Respiratory Electron-transport Chain (ETC) is a series of enzyme complexes embedded in the innermitochondrialmembrane, which oxidize NADH and QH2. (slideserve.com)
  • The passage of electrons down the electron transport chain appears to provide the energy for the active transport of hydrogen ions across the membrane from the mitochondrial matrix. (jiskha.com)
  • What role do high-energy electrons play in the electron transport chain? (jiskha.com)
  • a. high energy electrons move through the electron transport chain. (jiskha.com)
  • Provide electron to the electron transport chain in the form of NADH c. make ATP d. (jiskha.com)
  • In the electron transport chain, electrons from FADH2 are eventually used to reduce O2 into H2O. (jiskha.com)
  • The nonlinear lattice is modeled as a classical one-dimensional Morse chain and the dynamics of the electrons are considered in the tight-binding approximation. (ucm.es)
  • Electron Transport Chain and O2 Debt and LA fermentation? (biology-online.org)
  • which goes to the Electron transport chain. (biology-online.org)
  • Both the respiratory and photosynthetic electron transport chains are major sites of premature electron leakage to oxygen, thus being major sites of superoxide production and drivers of oxidative stress . (thefullwiki.org)
  • But, if electrons were added directly to oxygen, the reaction probably would produce enough heat to damage the cells and result in too small an amount of captured energy to be a significant source for future energy needs. (cliffsnotes.com)
  • Oxygen is the ultimate electron receiver, being reduced to water as a waste product, while helping to serve construct adenosine triphosphate by the transfer of electrons. (enotes.com)
  • labeled IV), which uses the electrons and hydrogen ions to reduce molecular oxygen to water. (wikipedia.org)
  • Here a series of reactions occurs in which electrons are transported to meet up with oxygen from respiration. (sciencephoto.com)
  • While contained by the third complex, the electrons interact with oxygen and hydrogen ions. (nodak.edu)
  • Electrons are finally donated to oxygen. (wiley.com)
  • Besides maintenance of electron flux, AOXs can reduce the reactive oxygen species (ROS) levels in situations when Complexes III and IV are unable to function properly. (plantphysiol.org)
  • In this biochemical reaction, electrons are passed along the cytochromes of a cell or mitochondrial membrane and are ultimately accepted by oxygen, producing water. (thefreedictionary.com)
  • The oxygen evolution and Q A- to Q B(Q B-) electron transfer measured by flash-induced fluorescence decay remained similar in all samples studied. (lu.se)
  • When oxygen accepts electrons, water is produced as a byproduct. (mhhe.com)
  • The most abundant electron carrier, coenzyme Q (CoQ) , carries electrons and hydrogen atoms between the others. (cliffsnotes.com)
  • Each hydrogen atom is split into its constituent H + (hydrogen ion) and electron. (s-cool.co.uk)
  • The hydrogen loses its electron, becomes the aforementioned proton gradient (H+), while the NAD+ couples with another molecule, on the way to producing ATP. (enotes.com)
  • This last electron, sorry the electron then gets past here to this last complex where again hydrogen ions are moved across the membrane and the used up energy electrons. (brightstorm.com)
  • Electron donation to the first complex (blue) and hydrogen ion pumping are coupled. (nodak.edu)
  • This means that when electrons are moved, hydrogen ions move too. (asu.edu)
  • What is the purpose of transporting the transporting the hydrogen ions across the membrane? (jiskha.com)
  • As a result of the oxidation of NADH and FADH2, electrons are released. (sparknotes.com)
  • More NADH and FADH2 carrying high energy electrons are sent off to the electron transport system. (brightstorm.com)
  • And what they do is they take the high energy electrons that are being carried by NADH or FADH2 and they pass them one to the next which is why collectively it's called an electron transport system. (brightstorm.com)
  • The second phase, the citric acid cycle, creates high-energy electrons by passing the broken-down glucose through several chemical reactions. (reference.com)
  • Now as I said it's the last step of aerobic respiration what it does it uses the high energy electrons that were generated by the cell doing glycolsis and the Krebs cycle putting them onto high energy electrons and then the electron transport system uses those high energy electrons to make some ATP. (brightstorm.com)
  • Now the electron transport system is this last step here, so we began with glycolsis breaking apart the glucose forming pyruvate and spitting off some high energy electrons in the form, are being carried on the electron carrier NADH. (brightstorm.com)
  • Oxidative respiration produces adenosine triphosphate through the mitochondrial electron transport system controlling the energy supply of plant cells. (plantphysiol.org)
  • The functionality of chlororespiratory electron transfer pathway under iron restricted conditions is also discussed. (frontiersin.org)
  • The results indicate that SA is both an uncoupler and an inhibitor of mitochondrial electron transport and suggest that this underlies the induction of some genes by SA. (plantphysiol.org)
  • Here we describe a mitochondrial pentatricopeptide repeat (PPR) domain protein, PPR40, which provides a signaling link between mitochondrial electron transport and regulation of stress and hormonal responses in Arabidopsis ( Arabidopsis thaliana ). (plantphysiol.org)
  • Thus, under stress the mitochondrial electron transport relies on the functions of AOXs, which can bypass the blocked proton pumping Complex III ( Vanlerberghe and Ordog, 2002 ). (plantphysiol.org)
  • These results are not consistent with previously proposed redox-shuttling mechanisms but suggest that the flavin/OM c- Cyts interaction regulates the extent of extracellular electron transport coupled with intracellular metabolic activity. (pnas.org)
  • Outside the cell, both Shewanella and Geobacter secrete nanometer scale diameter, micrometer scale long proteinaceous filaments, referred to as pili and microbial nanowires ( 7 ), that extend from their outer surfaces into the extracellular matrix (ECM) thought to be involved in extracellular electron transport processes, including cell-to-cell electron transfer ( 8 ) and reduction of insoluble oxidants ( 9 ). (pnas.org)
  • An alanine was substituted for each of the five aromatic amino acids in the carboxyl terminus of PilA, the region in which G. sulfurreducens PilA differs most significantly from the PilAs of microorganisms incapable of long-range extracellular electron transport. (asm.org)
  • The finding that a strain of G. sulfurreducens that produces pili with low conductivity is limited in these extracellular electron transport functions provides further insight into these environmentally significant processes. (asm.org)
  • The mechanisms for long-range extracellular electron transport in Geobacter species are of interest because of the important role that Geobacter species play in the biogeochemistry of a diversity of anaerobic soils and sediments and in several bioenergy strategies. (asm.org)
  • Electron transport is the last stage of cell respiration. (reference.com)
  • One such essential process is electron transport, which powers all life forms by shuttling electrons between key protein complexes. (medicalnewstoday.com)
  • Why Do Some Atoms Gain or Lose Electrons to Form Ions? (reference.com)
  • Atoms gain or lose electrons based on their respective electron affinity. (reference.com)
  • Many of the latter are cytochromes (proteins with an iron‐containing porphyrin ring attached) where the electron exchanges take place on the iron atoms. (cliffsnotes.com)
  • We propose to use ultracold-fermionic atoms in optical lattices to quantum-simulate electronic transport in quantum-cascade-laser structures. (osapublishing.org)
  • instead it is a mobile electron carrier and can float within the inner membrane, where it can transfer electrons from Complex I and Complex II to Complex III. (cliffsnotes.com)
  • The electron carriers are at successively lower energy levels hence, as the electron moves on from one carrier to the next some energy is released. (s-cool.co.uk)
  • Several compounds that prevent enzymatic reoxidation of plastoquinol in thylakoid membranes at the Qz site or withdraw electrons from this lipophilic electron carrier inhibited desaturation in the dark. (biomedsearch.com)
  • The donated electrons are then passed to the first mobile carrier protein (pink). (nodak.edu)
  • N- or B-doped carbon nanotubes (CNTs) uniformly dispersed in the active layer of P3HT/PCMB (poly (3-hexylthiophene/[6,6]-phenyl-C 61 -butyric acid methyl ester) bulk-heterojunction solar cells selectively enhance electron or hole transport and eventually help carrier collection. (wiley.com)
  • Despite its potential for adoption in these applications, an understanding of its carrier transport properties is still lacking. (aps.org)
  • 5. The cation requirement for equal inhibitory effect is parallel with the reciprocals of the transport affinities for the 'physiological K-carrier' (as taken from Conway & Duggan, 1958). (biochemj.org)
  • R. Photosynthetic Electron Carriers. (worldcat.org)
  • Such transport could in principle be described by means of Boltzmann transport equation (BTE) for charge carriers. (hindawi.com)
  • The structures are electrically connected by lipid-soluble electron carriers and water-soluble electron carriers. (wikipedia.org)
  • By analogy with other systems, this desaturation might be expected to involve electron carriers. (biomedsearch.com)
  • Electrons flow from different electron donors to the quinone carriers of the cell membrane (UQ) and are then transferred either to the bc1 complex or to the Cyo or CIO terminal ubiquinol oxidases. (wiley.com)
  • In this talk, I will review our recent theoretical and experimental efforts to establish the fundamental laws that govern the thermal transport in a variety of nanoscale systems in which the heat flow is dominated by different carriers: electrons, phonons, and photons. (cea.fr)
  • However, it is not known how protein phosphorylation affects the partial electron transport reactions in PS II. (lu.se)
  • For example, in the case of Shewanella , it is proposed that the CymA-MtrA-MtrC complex comprised of 3 multiheme c -type cytochromes totaling 24 hemes acts as a multistep conduit that conducts respired electrons originating in the cytoplasm from the inner membrane through the periplasm and outer membrane to the cell outer surface ( 4 ⇓ - 6 ). (pnas.org)
  • Electron flow through Complex II transfers proton(s) through the membrane into the intermembrane space. (cliffsnotes.com)
  • In chloroplasts, photosynthetic electron transport generates a proton gradient across the thylakoid membrane which then drives ATP synthesis via ATP synthase. (edu.au)
  • The electrons must travel through special proteins stuck in the thylakoid membrane. (asu.edu)
  • By moving step-by-step through these, electrons are moved in a specific direction across a membrane. (asu.edu)
  • Complex I and Complex II direct electrons to coenzyme Q. Complex I, also called NADH‐coenzyme Q reductase, accepts electrons from NADH. (cliffsnotes.com)
  • Complex II, also known as succinate‐coenzyme Q reductase, accepts electrons from succinate formed during the TCA cycle. (cliffsnotes.com)
  • Apparently, conformational changes in the proteins of Complex I also are involved in the mechanism of proton translocation during electron transport. (cliffsnotes.com)
  • Genes required for nitrogen fixation can be considered as three functional modules encoding electron-transport components (ETCs), proteins required for metal cluster biosynthesis, and the 'core' nitrogenase apoenzyme, respectively. (jic.ac.uk)
  • We are interested in using electron microscopy to solve the structure of mitochondrial transport proteins. (cam.ac.uk)
  • Calculations considering the interaction of electrons with acoustic phonons provide a reasonable description of our experimental findings. (aps.org)
  • first electrons go through the second photosystem and second they go through the first? (asu.edu)
  • Electrons first travel through photosystem II and then photosystem I. (asu.edu)
  • While at photosystem II and I, the electrons gather energy from sunlight. (asu.edu)
  • Succinate dehydrogenase, also known as succinate-CoQ reductase, receives electrons into the quinone pool from succinate and transfers them to to Q. Complex II has four subunits. (news-medical.net)
  • The energized electrons are then used to make NADPH. (asu.edu)
  • PINK1 is mutated in Parkinson's disease (PD), and mutations cause mitochondrial defects that include inefficient electron transport between complex I and ubiquinone. (rupress.org)
  • 1. Ubiquinone (Q)Q is a lipid soluble molecule that diffuses within the lipid bilayer, accepting electrons from Complex I and Complex II and passing them to Complex III. (slideserve.com)
  • Extracellular redox-active compounds, flavins and other quinones, have been hypothesized to play a major role in the delivery of electrons from cellular metabolic systems to extracellular insoluble substrates by a diffusion-based shuttling two-electron-transfer mechanism. (pnas.org)
  • can acquire energy by coupling intracellular oxidation of organic matter with extracellular electron transfer to an anode (an electrode poised at a metabolically oxidizing potential), forming a biofilm extending many cell lengths away from the anode surface. (pnas.org)
  • Low-temperature electronic transport through macromolecules and characteristics of intramolecular electron transfer. (ebscohost.com)
  • Long-distance electron transfer (ET) plays an important part in many biological processes. (ebscohost.com)
  • In describing the dynamics of electron transfer or charge transport, the reorganization energy and the spectral density function describe the influence of nuclei motion to the transporting electron. (rsc.org)
  • IMPORTANCE Extracellular electron transfer by Geobacter species plays an important role in the biogeochemistry of soils and sediments and has a number of bioenergy applications. (asm.org)
  • We study in detail the role of thermal factors on the electron transfer. (ucm.es)
  • We focus on the mutual drag between electron and phonon transport as a result of 'momentum' transfer, which happens only when there are at least two phonon degrees of freedom. (dtu.dk)
  • Interference of electron transport inhibitors with desaturation of monogalactosyl diacylglycerol in intact chloroplasts. (biomedsearch.com)
  • The effects of electron transport inhibitors on chloroplast lipid-linked desaturation were therefore investigated. (biomedsearch.com)
  • Inhibitors of cyclic electron transport interfered with desaturation only at rather high concentrations or not at all. (biomedsearch.com)
  • It transfers electrons from NADH to coenzyme Q10. (news-medical.net)
  • The electrons are then transferred through iron-sulfur clusters to coenzyme Q10. (news-medical.net)
  • Coenzyme Q is capable of accepting either one or two electrons to form either a semiquinone or hydroquinone form. (cliffsnotes.com)
  • VSEPR, or valence shell electron pair repulsion, is a model used to predict the geometry of a molecule. (reference.com)
  • In bacteria, the only electron chauffeur is a molecule called menaquinone (MK) that has species-specific variations in its structure. (medicalnewstoday.com)
  • misc{etde_475728, title = {Electron thermal transport in tokamak plasmas} author = {Konings, J A} abstractNote = {The process of fusion of small nuclei thereby releasing energy, as it occurs continuously in the sun, is essential for the existence of mankind. (osti.gov)
  • It has been proposed that long-range electron transport in such biofilms occurs through a network of bound redox cofactors, thought to involve extracellular matrix c -type cytochromes, as occurs for polymers containing discrete redox moieties. (pnas.org)
  • For all materials, we find that electron velocity overshoot only occurs when the electric field is increased to a value above a certain critical field, unique to each material. (scirp.org)
  • The reaction begins when NADH binds to Complex I, transferring two electrons to the flavin mononucleotide (FMN) prosthetic group, resulting in the formation of FMNH2. (news-medical.net)
  • Importantly, this flavin/OM c- Cyts interaction was found to facilitate a one-electron redox reaction via a semiquinone, resulting in a 10 3 - to 10 5 -fold faster reaction rate than that of free flavin. (pnas.org)
  • A pronounced semiconductor-to-metal transition is observed under 254 nm UV irradiation, as a consequence of the reduction of electron mobility arising from the drastically enhanced Coulomb interactions. (upmc.fr)
  • These features are consistent with the fact that the modulation of the intragap states results in reduction of interfacial recombination as well as the improved charge selectivity and electron transport properties of the ETLs. (diva-portal.org)
  • Clear evidence is reported for the first time of a rapid localized reduction of core electron energy diffusivity during the formation of an electron internal-transport barrier. (epfl.ch)
  • This crucial observation, and the correlation of the transition with the time and location of the magnetic shear reversal, lend support to models attributing the reduced transport to the local properties of a zero-shear region, in contrast to models predicting a gradual reduction due to a weak or negative shear. (epfl.ch)
  • Here, we report measurements of electron transport in actively respiring Geobacter sulfurreducens wild type biofilms using interdigitated microelectrode arrays. (pnas.org)
  • Measurements when one electrode is used as an anode and the other electrode is used to monitor redox status of the biofilm 15 μm away indicate the presence of an intrabiofilm redox gradient, in which the concentration of electrons residing within the proposed redox cofactor network is higher farther from the anode surface. (pnas.org)
  • Comparison with gate measurements, when one electrode is used as an electron source and the other electrode is used as an electron drain, suggests that there are multiple types of redox cofactors in Geobacter biofilms spanning a range in oxidation potential that can engage in electron transport. (pnas.org)
  • Ex situ conductivity measurements of individual filaments of Shewanella oneidensis MR-1 confirm their lengthwise conductivity when isolated from cells under specific conditions ( 10 , 11 ), and subsequent modeling of their current-voltage characteristics is consistent with multistep electron hopping involving redox cofactors proposed to be associated with these filaments ( 12 ⇓ - 14 ). (pnas.org)
  • Recently, fractional-quantized Hall effect was observed in suspended graphene (SG), a free-standing monolayer of carbon, where it was found to persist up to T=10 K. The best results in those experiments were obtained on micron-size flakes, on which only two-terminal transport measurements could be performed. (mit.edu)
  • We present low-temperature electron transport measurements of individual phenyleneâ€"ethynylene molecular wires, connected to nanometer-spaced gold electrodes. (ebscohost.com)
  • We report on nonlinear transport measurements in a two-dimensional electron gas hosted in GaAs/AlGaAs heterostructures. (aps.org)
  • Readers can therefore obtain a balancedview of charge and exciton transport, covering characterization techniques such as spectroscopy and current measurements together with quantitative models. (diva-portal.org)
  • In this study, a combination of thermoluminescence (TL), chlorophyll fluorescence, and P700 absorbance measurements have been used to elucidate the effects of iron deficiency in the photosynthetic electron transport of the marine diatom P. tricornutum . (frontiersin.org)
  • It has been proposed that Geobacter sulfurreducens requires conductive pili for long-range electron transport to Fe(III) oxides and for high-density current production in microbial fuel cells. (asm.org)
  • These results demonstrate that the pili of G. sulfurreducens must be conductive in order for the cells to be effective in extracellular long-range electron transport. (asm.org)
  • The E(k) relation describes how the particle moves inside the device, in addition to depicting useful information necessary for transport such as the density of states (DOS) and the particle velocity. (wikipedia.org)
  • Each time electrons are passed, there is the creation of a proton gradient (H+) that is available to create a thermodynamic potential to do mechanical work. (enotes.com)
  • The magnitude of the redox gradient seems to correlate with current, which is consistent with electron transport from cells in the biofilm to the anode, where electrons effectively diffuse from areas of high to low concentration, hopping between redox cofactors. (pnas.org)
  • The majority of these redox cofactors, however, seem to have oxidation potentials too negative to be involved in electron transport when acetate is the electron source. (pnas.org)
  • It is widely accepted that electron transport can occur over molecular-scale distances in biological systems by electron hopping among a small number of immobilized redox cofactors ( 1 , 2 ). (pnas.org)
  • There is growing awareness, however, of the possibility of electron transport over length scales much longer than previously thought possible in biological systems by using immobilized redox cofactors organized into electron transport conduits. (pnas.org)
  • While most ATP is produced using electron transport chains, some simpler organisms produce ATP through fermentation. (reference.com)
  • Electron transport chains capture energy in the form of a transmembrane electrochemical potential gradient. (thefullwiki.org)
  • In most organisms, however, the majority of ATP is generated by electron transport chains. (thefullwiki.org)
  • Since device fabrication facilities were not available before, an electron beam lithography (EBL) system has been installed. (europa.eu)
  • As HgTe will degrade or evaporate at normal baking temperatures for electron beam lithography (EBL) resists, an alternative method was developed. (ebscohost.com)
  • The effect of dimethyl sulphoxide on electron transport in chloroplasts. (biomedsearch.com)
  • It has been found that concentrations of DMSO up to 20% (v/v) do not inhibit electron transport in freshly isolated chloroplasts, but that higher concentrations start to cause inhibition. (biomedsearch.com)
  • However, in chloroplasts that have been aged for 8 to 24 hours by storage at 4 degrees C, the addition of DMSO at concentrations up to 20% causes stimulation of electron transport. (biomedsearch.com)