Chemiosmosis is the diffusion of ions across a membrane. More specifically, it relates to the generation of ATP by the movement of hydrogen ions across a membrane. ... It has been suggested that Net flux be merged into this article or section. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ...

An Ion gradient has potential energy and can be used to power chemical reactions when the ions pass through a channel (red).

Hydrogen ions (protons) will diffuse from an area of high proton concentration to an area of lower proton concentration. Peter Mitchell proposed that an electrochemical concentration gradient of protons across a membrane could be harnessed to make ATP. He likened this process to osmosis, the diffusion of water across a membrane, which is why it is called chemiosmosis. Image File history File links Chemiosmosis1. ... Image File history File links Chemiosmosis1. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Ion channels are pore-forming proteins that help to establish and control the small voltage gradient that exists across the plasma membrane of all living cells (see cell potential) by allowing the flow of ions down their electrochemical gradient. ... This article or section does not cite its references or sources. ... Peter D. Mitchell (September 29, 1920- April 10, 1992) was a British biochemist who was awarded the 1978 Nobel Prize for Chemistry for formulation of the chemiosmotic theory of mitochondrial function. ... In cellular biology, an electrochemical gradient refers to the electrical and chemical properties across a membrane. ... ATP may refer to: Chemistry/Biochemistry Adenosine triphosphate, the universal energy currency of all living organisms Companies Alberta Theatre Projects, a major Canadian theatre company. ... Osmosis is the movement of water through a selectively permeable membrane from a region of low solute potential to a region of high solute potential (or equivalently, from a region of high solvent potential to a region of low solvent potential). ...

ATP synthase is the enzyme that makes ATP by chemiosmosis. It allows protons to pass through the membrane using the kinetic energy to phosphorylate ADP making ATP. The generation of ATP by chemiosmosis occurs in chloroplasts and mitochondria as well as in some bacteria. An ATP synthase (EC 3. ... Kinetic energy is the energy that a body possesses as a result of its motion. ... Phosphorylation is the addition of a phosphate (PO4) group to a protein or a small molecule. ... ATP may refer to: Chemistry/Biochemistry Adenosine triphosphate, the universal energy currency of all living organisms Companies Alberta Theatre Projects, a major Canadian theatre company. ... Chloroplasts are organelles found in plant cells and eukaryotic algae which conduct photosynthesis. ... In cell biology, a mitochondrion is an organelle found in the cells of most eukaryotes. ... Subgroups Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular: bacterium) are microscopic, unicellular organisms. ...

The Chemiosmotic Theory

Youda Cao proposed the chemiosmotic hypothesis in 1961.^[1] The theory suggests essentially that most ATP synthesis in respiring cells comes from the electrochemical gradient across the inner membranes of mitochondria by using the energy of NADH and FADH₂ formed from the breaking down of energy rich molecules such as glucose. 1961 (MCMLXI) was a common year starting on Sunday (the link is to a full 1961 calendar). ... Adenosine 5-triphosphate (ATP), discovered in 1929 by Karl Lohmann,[1] is a multifunctional nucleotide primarily known in biochemistry as the molecular currency of intracellular energy transfer. ... Cellular respiration is the process in which the chemical bonds of energy-rich molecules such as glucose are converted into energy usable for life processes. ... Electrochemistry is the study of the electronic and electrical aspects of chemical reactions. ... Electron micrograph of a mitochondrion showing its mitochondrial matrix and membranes In cell biology, a mitochondrion (plural mitochondria) (from Greek μιτος or mitos, thread + κουδριον or khondrion, granule) is a membrane-enclosed organelle, found in most eukaryotic cells. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... Riboflavin Flavin is a tricyclic heteronuclear organic ring based on pteridine whose biochemical source is the vitamin riboflavin. ... Glucose (Glc), a monosaccharide (or simple sugar), is one of the most important carbohydrates in biology. ...

Chemiosmosis in a Mitochondrion

Molecules such as glucose are metabolized to produce acetyl CoA as an energy-rich intermediate. The oxidation of acetyl CoA in the mitochondrial matrix is coupled to the reduction of a carrier molecule such as NAD and FAD.^[2] The carriers pass electrons to the electron transport chain (ETC) in the inner mitochondrial membrane, which in turn pass them to other proteins in the ETC. The energy available in the electrons is used to pump protons from the matrix across the inner mitochondrial membrane, storing energy in the form of a transmembrane electrochemical gradient. The protons move back across the inner membrane through the enzyme ATP synthase. The flow of protons back into the matrix of the mitochondrion via ATP synthase provides enough energy for ADP to combine with inorganic phosphate to form ATP. The electrons and protons at the last pump in the ETC are taken up by oxygen to form water. Image File history File links Download high-resolution version (1013x781, 163 KB) This is the bitmap of the image Image:Etc3. ... Image File history File links Download high-resolution version (1013x781, 163 KB) This is the bitmap of the image Image:Etc3. ... Categories: Biochemistry stubs | Thiols ... The most fundamental reactions in chemistry are the redox processes. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD+) and nicotinamide adenine dinucleotide phosphate (NADP) are two important cofactors found in cells. ... In biochemistry, flavin adenine dinucleotide (FAD) is the precursor molecule to FADH2. ... The Electron is a fundamental subatomic particle that carries an electric charge. ... The Electron Transport Chain. ... In cellular biology, an electrochemical gradient refers to the electrical and chemical properties across a membrane. ... An ATP synthase (EC 3. ... Adenosine diphosphate, abbreviated ADP, is a nucleotide. ... Above is a ball-and-stick model of the inorganic phosphate molecule (HPO42−). Colour coding: P (orange); O (red); H (white). ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... Water is a tasteless, odourless substance that is essential to all known forms of life and is known as the universal solvent. ...

This was a radical proposal at the time, and was not well accepted. The prevailing view was that the energy of electron transfer was stored as a stable high potential intermediate, a chemically more conservative concept.

The problem with the older paradigm is that no high energy intermediate was ever found, and the evidence for proton pumping by the complexes of the electron transfer chain grew too great to be ignored. Eventually the weight of evidence began to favor the chemiosmotic hypothesis, and in 1978, Peter Mitchell was awarded the Nobel Prize in Chemistry.^[3] The electron transfer chain (also called the electron transport chain, ETC, e-train, or simply electron transport), is any series of protein complexes and lipid-soluble messengers that convert the reductive potential of energized electrons into a cross-membrane proton gradient. ... This is a list of Nobel Prize laureates in Chemistry from 1901 to 2006. ...

Chemiosmotic coupling is important for ATP production in chloroplasts^[4] and many bacteria.^[5] Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. ... Subgroups Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular: bacterium) are microscopic, unicellular organisms. ...

Chemiosmosis in Mitochondria

A diagram of chemiosmotic phosphorylation

The complete breakdown of glucose in the presence of oxygen is called cellular respiration. The last steps of this process occur in the mitochondria. High energy molecules NADH and FADH₂ are generated by the Kreb's cycle. These molecules dump electrons onto an electron transport chain to create a proton gradient across the inner mitochondrial membrane. ATP synthase is then used to generate ATP by chemiosmosis. This process is called oxidative phosphorylation because oxygen is the final electron acceptor in the mitochondrial electron transport chain. Image File history File links Download high-resolution version (500x700, 20 KB) A diagram of chemiosmotic phosphorylation. ... Image File history File links Download high-resolution version (500x700, 20 KB) A diagram of chemiosmotic phosphorylation. ... Glucose (Glc), a monosaccharide (or simple sugar), is one of the most important carbohydrates in biology. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... Cellular respiration is the process in which the chemical bonds of energy-rich molecules such as glucose are converted into energy usable for life processes. ... In cell biology, a mitochondrion is an organelle found in the cells of most eukaryotes. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... Flavin is also the name of a commune in the Aveyron département, in France Flavin adenine dinucleotide (FAD), upper, reduced FAD (FADH2), lower Flavin is a tricyclic heteronuclear organic ring whose biochemical source is the vitamin riboflavin. ... Overview of the citric acid cycle The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle) is a series of chemical reactions of central importance in all living cells that utilize oxygen as part of cellular respiration. ... The Electron Transport Chain. ... The Electron Transport Chain. ...

Chemiosmotic phosphorylation is the third, and final, biological pathway responsible for the production of ATP from an inorganic phosphate and an ADP molecule via oxidative phosphorylation. Adenosine 5-triphosphate (ATP), discovered in 1929 by Karl Lohmann,[1] is a multifunctional nucleotide primarily known in biochemistry as the molecular currency of intracellular energy transfer. ... Above is a ball-and-stick model of the inorganic phosphate molecule (HPO42−). Colour coding: P (orange); O (red); H (white). ... Adenosine diphosphate, abbreviated ADP, is a nucleotide. ... The Electron Transport Chain. ...

Occurring in the mitochondria of cells, the chemical energy of NADH, produced in the Krebs Cycle is used to build up a gradient of hydrogen ions (protons), with a higher concentration present in the mitochondrial cristae and a lower concentration in the mitochondrial matrix. This is the only step of oxidative phosphorylation for which oxygen is required: oxygen is used as an electron acceptor, combining with free electrons and hydrogen ions to form water. In cell biology, a mitochondrion is an organelle found in the cells of most eukaryotes. ... Cells in culture, stained for keratin (red) and DNA (green). ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle) is a series of chemical reactions of central importance in all living cells that utilize oxygen as part of cellular respiration. ... Cross-section of a mitochondrion, showing: (1) inner membrane, (2) outer membrane, (3) cristae, (4) matrix Cristae are the infoldings of the inner membrane of a mitochondrion. ... In biology, the word matrix is used for the material between animal or plant cells, or generally the material (or tissue) in which more specialized structures are embedded, and also specifically for one part of the mitochondrion. ...

Chemiosmosis in Plants

The Light reactions of photosynthesis generate energy by chemiosmosis. Chlorophyll loses an electron when energized by light. This electron travels down a photosynthetic electron transport chain ending on the high energy molecule NADPH. The electrochemical gradient generated across the thylakoid membrane drives the production of ATP by ATP Synthase. This process is known as photophosphorylation. The first stage of the photosynthetic system is the light-dependent reaction, which converts solar energy into chemical energy. ... The leaf is the primary site of photosynthesis in plants. ... The Electron Transport Chain. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... In cellular biology, an electrochemical gradient refers to the electrical and chemical properties across a membrane. ... Thylakoids (commonly referred to as Thylakoid membranes) are a phospholipid bilayer membrane-bound compartment internal to chloroplasts, and represent the majority of its internal structure. ... ATP may refer to: Chemistry/Biochemistry Adenosine triphosphate, the universal energy currency of all living organisms Companies Alberta Theatre Projects, a major Canadian theatre company. ... An ATP synthase (EC 3. ... Only two sources of energy are available to living organisms: sunlight and oxidation-reduction (redox) reactions. ...

Chemiosmosis in Bacteria

Bacteria also can use chemiosmosis to generate ATP. Cyanobacteria, green sulfur bacteria, and purple bacteria create energy by a process called photophosphorylation. These bacteria use the energy of light to create a proton gradient using a photosynthetic electron transport chain. Some nonphotosynthetic bacteria including E. coli also contains ATP synthase. Orders The taxonomy of the Cyanobacteria is currently under revision. ... Green sulfur bacteria - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... Purple bacteria or purple photosynthetic bacteria are proteobacteria that are phototrophic, i. ... Only two sources of energy are available to living organisms: sunlight and oxidation-reduction (redox) reactions. ... The Electron Transport Chain. ... An ATP synthase (EC 3. ...

In fact, mitochondria and chloroplasts are believed to have been formed when early eukaryotic cells ingested bacteria that could create energy using chemiosmosis. This is called the endosymbiotic theory. The endosymbiotic theory, now generally accepted by biologists, concerns the origins of mitochondria and plastids (e. ...

See also

• Mitochondrion
• Chloroplasts
• Electrochemical gradient
• Electron transfer chain
• Cytochrome
• ATP
• Cellular respiration
• Citric acid cycle
• Glycolysis
• Oxidative phosphorylation
• Chemiosmosis (University of Wisconsin)

Electron micrograph of a mitochondrion showing its mitochondrial matrix and membranes In cell biology, a mitochondrion (plural mitochondria) (from Greek μιτος or mitos, thread + κουδριον or khondrion, granule) is a membrane-enclosed organelle, found in most eukaryotic cells. ... Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. ... In cellular biology, an electrochemical gradient refers to the electrical and chemical properties across a membrane. ... The electron transfer chain (also called the electron transport chain, ETC, e-train, or simply electron transport), is any series of protein complexes and lipid-soluble messengers that convert the reductive potential of energized electrons into a cross-membrane proton gradient. ... Cytochromes are generally membrane-bound proteins that contain heme groups and carry out electron transport or catalyse reductive/oxidative reactions. ... Adenosine 5-triphosphate (ATP), discovered in 1929 by Karl Lohmann,[1] is a multifunctional nucleotide primarily known in biochemistry as the molecular currency of intracellular energy transfer. ... Cellular respiration is the process in which the chemical bonds of energy-rich molecules such as glucose are converted into energy usable for life processes. ... Overview of the citric acid cycle The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle) is a series of chemical reactions of central importance in all living cells that utilize oxygen as part of cellular respiration. ... Glycolysis is a biochemical pathway by which a molecule of glucose (Glc) is oxidized to two molecules of pyruvic acid (Pyr). ... The Electron Transport Chain. ...

References cited

1. ^ Peter Mitchell (1961). "Coupling of phosphorylation to electron and hydrogen transfer by a chemi-osmotic type of mechanism". Nature 191: 144–148.Entrez PubMed 13771349
2. ^ Alberts, Bruce, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts and Peter Walter (2002). “Proton Gradients Produce Most of the Cell's ATP”, Molecular Biology of the Cell. Garland. ISBN 0-8153-4072-9.
3. ^ The Nobel Prize in Chemistry 1978.
4. ^ Cooper, Geoffrey M.. “Figure 10.22: Electron transport and ATP synthesis during photosynthesis”, The Cell: A Molecular Approach, 2^nd edition, Sinauer Associates, Inc.. ISBN 0-87893-106-62000.
5. ^ Alberts, Bruce, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts and Peter Walter (2002). “Figure 14-32: The importance of H⁺-driven transport in bacteria”, Molecular Biology of the Cell. Garland. ISBN 0-8153-4072-9.

The Entrez logo The Entrez Global Query Cross-Database Search System allows access to databases at the National Center for Biotechnology Information (NCBI) website. ...

Other references

• biochemistry textbook reference, from the NCBI bookshelf — “18.4. A Proton Gradient Powers the Synthesis of ATP”, Jeremy M. Berg, John L. Tymoczko, Lubert Stryer Biochemistry (5th edition). W. H. Freeman.
• technical reference relating one set of experiments aiming to test some tenets of the chemiosmotic theory — Seiji Ogawa and Tso Ming Lee (1984). "The Relation between the Internal Phosphorylation Potential and the Proton Motive Force in Mitochondria during ATP Synthesis and Hydrolysis". Journal of Biological Chemistry 259 (16): 10004–10011.