A proton pump is an integral membrane protein that is capable of moving protons across the membrane of a cell, mitochondrion, or other subcellular compartment. In cell respiration, the pumps grab protons from the matrix, the space between the two enclosing membranes of the organelle, and release the protons within the inner membrane. The confined protons create a difference or gradient in both pH and electric charge (ignoring differences in buffer capacity) and establish an electrochemical potential that acts as a kind of battery or reservoir of stored energy for the cell. The inner cell membrane functions in a similar way to a dam in a river. It blocks protons from drifting back into the matrix. Since the pumping action is against the gradient, it requires work (energy). The process is directly analogous to bicycling uphill or charging a battery (storing up potential energy). It is important to remember that the proton pump does not create energy. Instead, the gradient stores energy for the appropriate time. Image File history File links No higher resolution available. ... An Integral Membrane Protein (IMP) is a protein molecule (or assembly of proteins) that is permanently attached to the biological membrane. ... In physics, the proton (Greek proton = first) is a subatomic particle with an electric charge of one positive fundamental unit (1. ... The cell membrane (also called the plasma membrane or plasmalemma) is a semipermeable lipid bilayer common to all living cells. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hook from Micrographia which is the origin of the word cell. Cells in culture, stained for keratin (red) and DNA (green). ... 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. ... 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. ... Schematic of typical animal cell, showing subcellular components. ... For other uses, see Gradient (disambiguation). ... The correct title of this article is . ... Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... A buffering agent adjusts the pH of a solution. ... Electrochemical potential is a thermodynamic measure that reflects energy from entropy and electrostatics and is typically invoked in molecular processes that involve diffusion. ... Mechanical work is a force applied through a distance, defined mathematically as the line integral of a scalar product of force and displacement vectors. ... Potential energy is the energy that is by virtue of the relative positions (configurations) of the objects within a physical system. ...

Some of the enzymes involved in the electron transport chain, such as ubiquinone, travel along the matrix, like freight boats, navigating up and down the river. Others such as NADH-Q reductase, act like ferryboats and cross the matrix. Enzymes that can cross the matrix may have a secondary role as proton pumps because they can deliver protons to the inner membrane. The Electron Transport Chain. ... Coenzyme Q (CoQ), also known as ubiquinone or ubiquinol, is a biologically active quinone with an isoprenoid side chain, related in structure to vitamin K and vitamin E. The oxidized structure of CoQ, or Q, is given here: The various kinds of Coenzyme Q can be distinguished by the number... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... A reductase is an enzyme which lowers the activation energy for a reduction reaction. ...

In bacteria, mitochondria and other ATP-producing organelles, reducing equivalents provided by electron transfer or photosynthesis power this translocation of protons. For example, the translocation of protons by cytochrome c oxidase is powered by reducing equivalents provided by reduced cytochrome c. In the plasma membrane proton ATPase and in the ATPase proton pumps of other cellular membranes, ATP itself powers this transport. Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... English chemists John Daniell (left) and Michael Faraday (right), both credited to be founders of electrochemistry as known today. ... 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. ... The leaf is the primary site of photosynthesis in plants. ... Cytochrome c oxidase The enzyme cytochrome c oxidase (PDB 2OCC, EC 1. ... Cytochrome c with heme c. ... Drawing of a cell membrane A component of every biological cell, the cell membrane (or plasma membrane) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... ATPases are a class of enzymes that catalyze the decomposition of adenosine triphosphate (ATP) into adenosine diphosphate (ADP) and a free phosphate ion. ...

The F_oF₁ ATP synthase of mitochondria and the CF₁ ATP ligase of chloroplasts, in contrast, usually conduct protons from high to low concentration across the membrane while drawing energy from this flow to synthesize ATP. To allow the passage of protons a proton channel temporarily opens in the inner membrane. An ATP synthase (EC 3. ... In biochemistry, a ligase (from the Latin verb ligāre — to bind or to glue together) is an enzyme that can catalyse the joining of two large molecules by forming a new chemical bond, usually with accompanying hydrolysis of a small chemical group pendant to one of the larger molecules. ... Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. ... 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. ...

Bacteriorhodopsin is a photosynthetic pigment used by archaea, most notably halobacteria. Bacteriorhodopsin is a photosynthetic pigment used by archaea, most notably halobacteria. ... The leaf is the primary site of photosynthesis in plants. ... Natural Ultramarine pigment in powdered form. ... Phyla / Classes Phylum Crenarchaeota Phylum Euryarchaeota     Halobacteria     Methanobacteria     Methanococci     Methanopyri     Archaeoglobi     Thermoplasmata     Thermococci Phylum Korarchaeota Phylum Nanoarchaeota Archaea (; from Greek αρχαία, ancient ones; singular Archaeum, Archaean, or Archaeon), also called Archaebacteria (), is a major division of living organisms. ... Genera Haloarcula Halobacterium Halobaculum Halococcus Haloferax Halogeometricum Halorubrum Haloterrigena Natrialba Natrinema Natronobacterium Natronococcus Natronomonas Natronorubrum The halobacteria are a family of archaea, found in water saturated or nearly saturated with salt. ...

See also

• transmembrane ATPase
• active transport
• cytochrome
• mitochondrion
• chloroplast
• electron transfer chain
• proton pump inhibitor
• ATP synthase
• V-ATPase
• GORD
• Kidney