An ion gradient is a concentration gradient of ions, it can be called an electrochemical potential gradient of ions across membranes. Ionophores are important for ion gradients. The chemiosmotic potential is used as energy storage, chemiosmotic coupling is one of several ways a thermodynamically unfavorable reaction can be driven by a thermodynamically favorable one, I.E by letting the ions diffuse through the high concentration side to the low concentration side through transmembrane proteins which can use them as energy. Several different types of ion gradients exist in biological systems, the most common one is the proton gradient. Transmembrane ATPases or transmembrane proteins with ATPase domains are often used for making and utilizing ion gradients. The enzyme Na+/K+ ATPase use ATP to make a sodium ion gradient and a potassium ion gradient. An ion gradient is a concentration gradient of ions, it can be called an electrochemical potential gradient of ions across membranes. ... An ion is an elementary particle or system of elementary particles with a net electric charge. ... In the above two images, the scalar field is in black and white, black representing higher values, and its corresponding gradient is represented by blue arrows. ... An ionophore is a substance that facilitates the transport of ions into or through the lipid bilayer of a cell membrane. ... Electrochemical potential is a thermodynamic measure that reflects energy from entropy and electrostatics and is typically invoked in molecular processes that involve diffusion. ... Na+/K+-ATPase (also known as the Na+/K+ pump or Na+/K+ exchanger) is an enzyme (EC 3. ...

Proton gradients

The proton gradient can be used as an intermediate energy storage for heat production and flagellar rotation. Additionally it is an interconvertible form of energy in active transport, electron potential generation, NADPH synthesis and ATP synthesis/hydrolysis. Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... Adenosine triphosphate (ATP) Adenosine triphosphate (ATP) is the nucleotide known in biochemistry as the molecular currency of intracellular energy transfer; that is, ATP is able to store and transport chemical energy within cells. ...

Some archaea, most notably halobacteria, make proton gradients by pumping in protons from the environment with the help of the solar driven enzyme bacteriorhodopsin, here it is used for driving the molecular motor enzyme ATP synthase to make the necessary conformational changes required to synthesize ATP. Phyla / Classes Phylum Crenarchaeota Phylum Euryarchaeota     Halobacteria     Methanobacteria     Methanococci     Methanopyri     Archaeoglobi     Thermoplasmata     Thermococci Phylum Korarchaeota Phylum Nanoarchaeota The Archaea are a major group of prokaryotes. ... 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. ... Bacteriorhodopsin is a photosynthetic pigment used by archaea, most notably halobacteria. ... An ATP synthase (EC 3. ...

Proton gradients are also made by bacteria by running ATP synthase in reverse, this is used to drive flagellas.

The F₁F_O ATP synthase is a reversible enzyme. Large enough quantities of ATP cause it to create a transmembrane proton gradient, this is used by fermenting bacteria which do not have an electron transport chain, and hydrolyze ATP to make a proton gradient, which they use for flagella and transport of nutrients into the cell. Properties In physics, the proton (Greek proton = first) is a subatomic particle with an electric charge of one positive fundamental unit (1. ... In the above two images, the scalar field is in black and white, black representing higher values, and its corresponding gradient is represented by blue arrows. ... A flagellum (plural, flagella) is a whip-like organelle that many unicellular organisms, and some multicellular ones, use to move about. ...

In respiring bacteria under physiological conditions, ATP synthase generally runs in the opposite direction, creating ATP while using the protonmotive force created by the electron transport chain as a source of energy. The overall process of creating energy in this fashion is termed oxidative phosphorylation. Same process takes place in mitochondria, were ATP synthase is located in the inner mitochondrial membrane (so that F₁-part sticks into mitochondrial matrix, were ATP synthesis takes place). Electrochemical potential is a thermodynamic measure that reflects energy from entropy and electrostatics and is typically invoked in molecular processes that involve diffusion. ... 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. ... Oxidative phosphorylation is a biochemical process in cells. ... In cell biology, a mitochondrion is an organelle found in the cells of most eukaryotes. ...

See also

• Transmembrane potential difference