As mitochondria contain ribosomes and DNA, and are only formed by the division of other mitochondria, it is generally accepted that they were originally derived from endosymbiotic prokaryotes. Studies of mitochondrial DNA, which is circular and employs a variant genetic code, show their ancestor was a member of the Proteobacteria [Futuyma 2005]. In particular, the pre-mitochondrion was probably related to the rickettsias. A few groups of unicellular eukaryotes lack mitochondria: the symbiotic microsporidians, metamonads, and entamoebi ...

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Mitochondrion, Mitochondrion - Mitochondrion structure, Mitochondrion - The mitochondrial matrix, Mitochondrion - Mitochondrial functions, Mitochondrion - Energy conversion, Mitochondrion - Use in population genetic studies, Mitochondrion - Origin, Mitochondrion - Reference, Mitochondrion - Mitochondrial structure, Mitochondrion - Fiction

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An equilibrium potential is the membrane voltage at which a particular ion is in equilibrium. The equilibrium potential (also called reversal potential or Nernst Potential) is the membrane voltage at which the voltage force exactly balances the concentration gradient force (see section above), thus the voltage at which the inward and outward flows of the ion are balanced (net current = zero), or in equilibrium. The equilibrium potential of a particular ion is designated by the notation Eion. In the previous section, ...

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Membrane potential, Membrane potential - The Ionic Basis of the resting potential, Membrane potential - Generation of the resting potential, Membrane potential - The number of ions involved in generating the resting potential, Membrane potential - Equilibrium potentials, Membrane potential - Resting potential revisited, Membrane potential - All other values of membrane potential, Membrane potential - Effects and implications

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From the viewpoint of biophysics, there is nothing particularly special about the resting membrane potential. It is merely the membrane potential that results from the membrane permeabilities that predominate when the cell is resting. At any given moment, there are two factors for an ion that determine how much influence that ion will have over the membrane potential of a cell. That ion's "driving force" and, That ion's permeability Intuitively, this is easy to understand. If the driving force is hi ...

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Membrane potential, Membrane potential - The Ionic Basis of the resting potential, Membrane potential - Generation of the resting potential, Membrane potential - The number of ions involved in generating the resting potential, Membrane potential - Equilibrium potentials, Membrane potential - Resting potential revisited, Membrane potential - All other values of membrane potential, Membrane potential - Effects and implications

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While cells expend energy to transport ions and establish a transmembrane potential, they use this potential in turn to transport other ions and metabolites such as sugar. The transmembrane potential of the mitochondria drives the production of ATP, which is the common currency of biological energy. Cells may draw on the energy they store in the resting potential to drive action potentials or other forms of excitation. These changes in the membrane potential enable communication with other cells (as with action potentials) or initiate changes inside the ...

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Membrane potential, Membrane potential - The Ionic Basis of the resting potential, Membrane potential - Generation of the resting potential, Membrane potential - The number of ions involved in generating the resting potential, Membrane potential - Equilibrium potentials, Membrane potential - Resting potential revisited, Membrane potential - All other values of membrane potential, Membrane potential - Effects and implications

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At its core, the genesis of every resting membrane potential is some sort of ion pump, exchanger or transporter. Any voltage, membrane potentials included, is a separation of charges across a resistive barrier. The typical membrane potential of a cell arises from the separation of potassium ions from intracellular immobile anions across the membrane of the cell. In order for this separation to occur, a concentration gradient of potassium ions must first be set up. While most descriptions of the genesis of membrane potential begin with ...

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Membrane potential, Membrane potential - The Ionic Basis of the resting potential, Membrane potential - Generation of the resting potential, Membrane potential - The number of ions involved in generating the resting potential, Membrane potential - Equilibrium potentials, Membrane potential - Resting potential revisited, Membrane potential - All other values of membrane potential, Membrane potential - Effects and implications

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At its core, the origin of every resting membrane potential is some sort of ion pump exchanger or transporter. Any voltage - membrane potentials included - is a separation of charges across a resistive barrier. The typical membrane potential of a cell arises from the separation of potassium ions from intracellular immobile anions across the membrane of the cell. In order for this separation to occur, a concentration gradient of potassium ions must first be set up. While most descriptions of the genesis of membrane potential begin with ...

See also:

Membrane potential, Membrane potential - The Ionic Basis of the resting potential, Membrane potential - Generation of the resting potential, Membrane potential - The number of ions involved in generating the resting potential, Membrane potential - Equilibrium potentials, Membrane potential - Resting potential revisited, Membrane potential - All other values of membrane potential, Membrane potential - Effects and implications

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Two different variation of electron transport are used during photosynthesis: Noncyclic electron transport produces NADPH + H+ and ATP. Cyclic electron transport produces only ATP. The noncyclic variety involves the participation of two different photosystems, while the cyclic is dependent on only one. Photosystem I uses light energy to reduce NADP+ to NADPH + H+, and is active in both noncyclic and cyclic electron transport. In cyclic mode ...

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Thylakoid, Thylakoid - Photosystems, Thylakoid - Electron transport chains, Thylakoid - ATP synthase

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Potentiostatic coulometry involves keeping the electrochemical potential at the working electrode (the electrode involved in the reaction) constant, which results in an exponential decrease in current as the reaction proceeds. This is because the potential at the working electrode is not equal to the potential of the entire cell. It is related by the equation: where R is the gas constant, n is the stoichiometric number of electrons, and See also:

Coulometry, Coulometry - Potentiostatic coulometry, Coulometry - Coulometric titration, Coulometry - Applications, Coulometry - Karl Fischer reaction, Coulometry - Determination of Film Thickness, Coulometry - Coulometers, Coulometry - Electronic coulometer, Coulometry - Electrochemical coulometers

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Substances that have the ability to oxidize (Commonwealth English oxidise) other substances are said to be oxidative and are known as oxidizing agents, oxidants or oxidizers. Put in another way, the oxidant removes electrons from the other substance, and is thus reduced itself. Oxidants are usually chemical substances with elements in high oxidation numbers (e.g. H2O2, MnO4-, CrO3, Cr2O72-, OsO4) or hig ...

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Redox, Redox - Oxidizing and reducing agents, Redox - Oxidation in the industry, Redox - Former meaning oxygen/hydrogen, Redox - Examples of redox reactions, Redox - Other examples, Redox - Redox reactions in biology

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A good example is the reaction between hydrogen and fluorine: H2 + F2 → 2HF We can write this overall reaction as two half-reactions: an oxidation reaction: H2 → 2H+ + 2e- and a reduction reaction: F2 + 2e- → 2F- Elements always have an oxidation number of zero. In the first half reaction hydrogen is oxidized from an oxidation number of zero to an oxidation number of +1. In the second half reaction fluorine is reduced from an oxi ...

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Redox, Redox - Oxidizing and reducing agents, Redox - Oxidation in the industry, Redox - Former meaning oxygen/hydrogen, Redox - Examples of redox reactions, Redox - Other examples, Redox - Redox reactions in biology

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Much biological energy is stored and released by means of redox reactions. Photosynthesis involves the reduction of carbon dioxide into sugars and the oxidation of water into molecular oxygen. The reverse reaction, respiration, oxidizes sugars to produce carbon dioxide and water. As intermediate steps, the reduced carbon compounds are used to reduce nicotinamide adenine dinucleotide (NAD+), which then contributes to the creation of a proton gradient, which drives the synthesis of adenosine triphosphate (ATP) and is maintained by the reduction of oxygen. In animal cells, mitochondria perform simil ...

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Redox, Redox - Oxidizing and reducing agents, Redox - Oxidation in the industry, Redox - Former meaning oxygen/hydrogen, Redox - Examples of redox reactions, Redox - Other examples, Redox - Redox reactions in biology

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Substances that have the ability to oxidize (Commonwealth English oxidise) other substances are said to be oxidative and are known as oxidizing agents, oxidants or oxidizers. Put in another way, the oxidant removes electrons from the other substance, and is thus reduced itself. Oxidants are usually chemical substances with elements in high oxidation numbers (e.g., H2O2, MnO4-, CrO3, Cr2O72-, OsO4) or hi ...

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Redox, Redox - Oxidizing and reducing agents, Redox - Oxidation in the industry, Redox - Former meaning oxygen/hydrogen, Redox - Examples of redox reactions, Redox - Other examples, Redox - Redox reactions in biology

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A good example is the reaction between hydrogen and fluorine: H2 + F2 → 2HF We can write this overall reaction as two half-reactions: an oxidation reaction: H2 → 2H+ + 2e- and a reduction reaction: F2 + 2e- → 2F- Elements always have an oxidation number of zero. In the first half reaction hydrogen is oxidized from an oxidation number of zero to an oxidation number of +1. In the second half, reaction fluorine is reduced from an oxi ...

See also:

Redox, Redox - Oxidizing and reducing agents, Redox - Oxidation in the industry, Redox - Former meaning oxygen/hydrogen, Redox - Examples of redox reactions, Redox - Other examples, Redox - Redox reactions in biology

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When closed, sodium channels help to maintain a neuron's resting potential, and when open, they allow sodium ions to flow rapidly down their electrochemical gradient, thus depolarizing the neuron. Voltage-gated Na+ channels are probably genetically related to potassium and calcium channels; in fact, a change of two amino acids will cause the channel to behave as a calcium channel (Kandel, 2000, p. 164). ...

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Sodium ion channel, Sodium ion channel - Voltage-gated sodium channels, Sodium ion channel - Structure and gating, Sodium ion channel - Impermeability to other ions, Sodium ion channel - Role in action potential, Sodium ion channel - Reference

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Although the word comes from the Greek for "rubbing", tribos, the two materials only need to come into contact and then separate for electrons to be exchanged. After coming into contact, a chemical bond is formed between some parts of the two surfaces, called adhesion, and charges move from one material to the other to equalize their electrochemical potential. This is what creates the net charge imbalance between the objects. When separated, some of the bonded atoms have a tendency to keep extra electrons, and some a tendency to give ...

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Triboelectric effect, Triboelectric effect - Series, Triboelectric effect - Effect, Triboelectric effect - Utilization, Triboelectric effect - External articles and references

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The medullary thick ascending limb remains impermeable to water. Sodium, potassium (K+) and chloride (Cl-) ions are reabsorbed by active transport. K+ diffuses along its concentration gradient, back into the lumen of the ascending limb. This generates a positive electrochemical potential difference in the lumen. The electrical gradient drives more reabsorption of Na+, as well as other cations such as magnesium (Mg2+). Loop diuretics block ...

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Loop of Henle, Loop of Henle - Descending limb, Loop of Henle - Thin ascending limb, Loop of Henle - Medullary thick ascending limb, Loop of Henle - Cortical thick ascending limb, Loop of Henle - Blood supply

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Baghdad Battery - Electrical. Copper and iron form an electrochemical couple, so that in the presence of any electrolyte, an electric potential (voltage) will be produced. König had observed a number of very fine silver objects from ancient Iraq which were plated with very thin layers of gold, and speculated that they were electroplated using batteries of these "cells". After the Second World War, Willard Gray demonstrated current production by a reconstruction of the inferred battery design when filled with grape juice. W. Jansen experimented with benzoquinone (some beetles produce quino ...

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Baghdad Battery, Baghdad Battery - Description, Baghdad Battery - Dating, Baghdad Battery - Speculations on function, Baghdad Battery - Electrical, Baghdad Battery - Nonelectrical, Baghdad Battery - Controversy, Baghdad Battery - Comparisons, Baghdad Battery - External articles references resources, Baghdad Battery - Further reading and other references

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In science and technology, a battery is a device that stores energy and makes it available in an electrical form. Batteries consist of electrochemical devices such as one or more galvanic cells (or, more recently, fuel cells). The first possible evidence of batteries in history are the Baghdad Batteries from sometime between 250 BCE and 640 CE. The modern development of batteries started with the Voltaic pile developed by the Italian physicist Alessandro Volta in 1800. The worldwide battery industry generates 48 billion dollars ...

Including:

Battery electricity - Cell vs. battery Battery electricity - Electrical component Battery electricity - Battery concepts
Battery electricity - Battery lifetime Battery electricity - Battery explosion
Battery electricity - Common battery types
Battery electricity - Rechargeable and disposable batteries Battery electricity - Homemade cells Battery electricity - Traction batteries Battery electricity - Flow batteries
Battery electricity - Common battery sizes Battery electricity - List of battery sizes Battery electricity - History Battery electricity - Environmental considerations Battery electricity - The future
Battery electricity - People/inventors Battery electricity - Related electrical topics Battery electricity - Related electronics concepts Battery electricity - Chemicals used in construction Battery electricity - Related inventions Battery electricity - Other

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In science and technology, a battery is a device that stores energy and makes it available in an electrical form. Batteries consist of electrochemical devices such as one or more galvanic cells (or, more recently, fuel cells). The first possible evidence of batteries in history are the Baghdad Batteries from sometime between 250 BCE and 640 CE. The modern development of batteries started with the Voltaic pile developed by the Italian physicist Alessandro Volta in 1800. The worldwide battery industry generates 48 billion dollars ...

Including:

Battery electricity - Cell vs. battery Battery electricity - Electrical component Battery electricity - Battery concepts
Battery electricity - Battery capacity Battery electricity - Battery lifetime Battery electricity - Battery explosion
Battery electricity - Common battery types
Battery electricity - Rechargeable and disposable batteries Battery electricity - Homemade cells Battery electricity - Traction batteries Battery electricity - Flow batteries
Battery electricity - Common battery sizes Battery electricity - List of battery sizes Battery electricity - History Battery electricity - Environmental considerations Battery electricity - The future
Battery electricity - People/inventors Battery electricity - Related electrical topics Battery electricity - Related electronics concepts Battery electricity - Chemicals used in construction Battery electricity - Related inventions Battery electricity - Other

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Battery electricity - Battery capacity. The capacity of a battery to store charge is often expressed in ampere hours (1 A·h = 3600 coulombs). If a battery can provide one ampere (1 A) of current (flow) for one hour, it has a real-world capacity of 1 A·h. If it can provide 1 A for 100 hours, its capacity is 100 A·h. Because of the chemical reactions within the cells, the capacity of a battery depends on the discharge conditions such as the magnitude of the current, the duration of the current, the allowable terminal ...

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Battery electricity, Battery electricity - Cell vs. battery, Battery electricity - Electrical component, Battery electricity - Battery concepts, Battery electricity - Battery capacity, Battery electricity - Battery lifetime, Battery electricity - Battery explosion, Battery electricity - Common battery types, Battery electricity - Rechargeable and disposable batteries, Battery electricity - Homemade cells, Battery electricity - Traction batteries, Battery electricity - Flow batteries, Battery electricity - Common battery sizes, Battery electricity - List of battery sizes, Battery electricity - History, Battery electricity - Environmental considerations, Battery electricity - The future, Battery electricity - People/inventors, Battery electricity - Related electrical topics, Battery electricity - Related electronics concepts, Battery electricity - Chemicals used in construction, Battery electricity - Related inventions, Battery electricity - Other

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Initial research indicates that nanotechnology batteries employing carbon nanotubes will have twice the life of traditional modern batteries. A new form of battery is in development called Power Paper. This thin, flexible battery comes in the form of ink cells which can be printed on to virtually any surface and produce power. Future cell management is able to condition one cell while the others are in ...

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Battery electricity, Battery electricity - Cell vs. battery, Battery electricity - Electrical component, Battery electricity - Battery concepts, Battery electricity - Battery capacity, Battery electricity - Battery lifetime, Battery electricity - Battery explosion, Battery electricity - Common battery types, Battery electricity - Rechargeable and disposable batteries, Battery electricity - Homemade cells, Battery electricity - Traction batteries, Battery electricity - Flow batteries, Battery electricity - Common battery sizes, Battery electricity - List of battery sizes, Battery electricity - History, Battery electricity - Environmental considerations, Battery electricity - The future, Battery electricity - People/inventors, Battery electricity - Related electrical topics, Battery electricity - Related electronics concepts, Battery electricity - Chemicals used in construction, Battery electricity - Related inventions, Battery electricity - Other

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