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.

How it works

This proton motive force created by the ETC is used to power membrane transporters and adenosine triphosphate synthesis by ATP synthase (aka the F_oF₁ particle). They are used in photophosphorylation and respiration. Adenosine 5-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. ... An ATP synthase (EC 3. ... The first stage of the photosynthetic system is the light-dependent reaction, which converts solar energy into chemical energy. ... 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 eukaryotes, including humans, an ETC is found spanning the inner mitochondrial membrane (crista) and accepts electrons from electron donors such as NADH or succinate, shuttles these electrons from within the mitochondrial matrix across the inner mitochondrial membrane into the intermembrane space, where they ultimately reduce oxygen. Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... In cell biology, a mitochondrion is an organelle found in the cells of most eukaryotes. ... It has been suggested that Net flux be merged into this article or section. ... 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. ... Properties The electron is a fundamental subatomic particle which carries a negative electric charge. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... The acid succinic acid has the formula: HOOC-CH2-CH2-COOH At room temperature (25 degrees Celcius), pure succinic acid is a solid that forms colorless, odorless prisms. ... 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. ... The intermembrane space is the region between the inner membrane and the outer membrane of a mitochondrion or a chloroplast. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ...

Five complexes

There are five complexes normally associated with the mitochondrial electron transfer chain. All of these are proteolipid complexes, with the first four containing either flavins, iron-sulfur clusters, copper centers, or heme moieties. A lipoprotein is a biochemical assembly that contains both proteins and lipids and may be structural or catalytic in function. ... Riboflavin Flavin is a tricyclic heteronuclear organic ring whose biochemical source is the vitamin riboflavin. ... An iron-sulfur cluster is a structural motif found in certain metalloproteins, such as the ferredoxins, as well as NADH dehydrogenase and Coenzyme Q - cytochrome c reductase of the electron transfer system. ... General Name, Symbol, Number copper, Cu, 29 Chemical series transition metals Group, Period, Block 11, 4, d Appearance metallic brown Atomic mass 63. ... A hæm or heme is a metal-containing cofactor that consists of an iron atom contained in the center of a large heterocyclic organic ring called a porphyrin. ...

Complex I (proton pump)

NADH dehydrogenase, also called NADH coenzyme Q reductase. 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, thereby creating a difference or gradient in both pH and electrical charge (ignoring differences in buffer capacity) and tending to establish an electrochemical potential. ... Categories: Biochemistry stubs | Cellular respiration | EC 1. ...

Complex II

Succinate - coenzyme Q reductase. Complex II is part of the Krebs cycle and does not pump protons. Succinate—coenzyme Q reductase (EC 1. ... 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. ...

Complex III (proton pump)

Coenzyme Q - cytochrome c reductase. CoQ Cytochrome c reductase The Coenzyme Q - cytochrome c reductase complex, sometimes called the cytochrome bc1 complex, and at other times Complex III, is the third complex in the electron transfer chain (PDB 1KYO, EC 1. ...

Cytochrome c

Cytochrome c is also an essential part of the electron transfer chain. It is a soluble protein loosely associated with the inner mitochondrial membrane, and transfers electrons between Complexes III and IV. Cytochrome C (horse heart: PDB 1HRC) is a small heme protein found loosely associated with the inner membrane of the mitochondrion. ...

Complex IV (proton pump)

Cytochrome c oxidase. Complex IV is the terminus of the electron transfer chain, where oxygen from the lungs is reduced by electrons and hydrogen protons (provided by NADH and/or FADH2) to make water. Cytochrome c oxidase The enzyme cytochrome c oxidase (PDB 2OCC, EC 1. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... 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. ... Water (from the Old English word wæter; c. ...

Complex V

ATP synthase, also known as the F_oF₁ particle. Complex V uses the electrochemical potential generated to create ATP. An ATP synthase (EC 3. ... Electrochemical potential is a thermodynamic measure that reflects energy from entropy and electrostatics and is typically invoked in molecular processes that involve diffusion. ... Adenosine 5-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. ...

Inhibition

The electron transfer chain can be inhibited by various poisons. Among them we can cite carbon monoxide, cyanide, azide, antimycin, amytal and rotenone. The skull and crossbones symbol traditionally used to label a poisonous substance. ... Carbon monoxide, chemical formula CO, is a colourless, odourless, flammable and highly toxic gas. ... A cyanide is any chemical compound that contains the group C≡N, with the carbon atom triple-bonded to the nitrogen atom. ... An azide is a N3- anion, or a reactive group in organic chemistry where a carbon substituent is attached as RN3. ... Antimycin is an antibiotic which inhibits the electron transport chain between cytochrome B and cytochrome C Categories: Biochemistry stubs | Antibiotics ... Amobarbital is a barbiturate with sedative-hypnotic and analgesic properties . ... Rotenone (CAS number 83-79-4) is a colorless-to-red, odorless solid. ...

See also

• cytochrome
• mitochondrion
• chloroplast
• oxidative phosphorylation

Cytochromes are generally membrane-bound proteins that contain heme groups and carry out electron transport or catalyse reductive/oxidative reactions. ... Mitochondria are visible as thread-like structures in the light microscope. ... The inside of a chloroplast The inside of a chloroplast Chloroplasts are organelles found in plant cells and eukaryotic algae which conduct photosynthesis. ... Oxidative phosphorylation is a biochemical process in cells. ...

External links

• electron transport chain