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Sliding Filament Theory
The sliding filament theory explains the mechanism of muscle contraction based on muscle proteins that slide past each other to generate movement. According to the sliding filament theory, the myosin (thick filaments) of muscle fibers slide past the actin (thin filaments) during muscle contraction, while the two groups of filaments remain at relatively constant length. The theory was independently introduced in 1954 by two research teams, one consisting of Andrew Huxley and Rolf Niedergerke from the University of Cambridge, and the other consisting of Hugh Huxley and Jean Hanson from the Massachusetts Institute of Technology. It was originally conceived by Hugh Huxley in 1953. Andrew Huxley and Niedergerke introduced it as a "very attractive" hypothesis. Before the 1950s there were several competing theories on muscle contraction, including electrical attraction, protein folding, and protein modification. The novel theory directly introduced a new concept called cross-bridge theo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarcomere
A sarcomere (Greek σάρξ ''sarx'' "flesh", μέρος ''meros'' "part") is the smallest functional unit of striated muscle tissue. It is the repeating unit between two Z-lines. Skeletal muscles are composed of tubular muscle cells (called muscle fibers or myofibers) which are formed during embryonic myogenesis. Muscle fibers contain numerous tubular myofibrils. Myofibrils are composed of repeating sections of sarcomeres, which appear under the microscope as alternating dark and light bands. Sarcomeres are composed of long, fibrous proteins as filaments that slide past each other when a muscle contracts or relaxes. The costamere is a different component that connects the sarcomere to the sarcolemma. Two of the important proteins are myosin, which forms the thick filament, and actin, which forms the thin filament. Myosin has a long, fibrous tail and a globular head, which binds to actin. The myosin head also binds to ATP, which is the source of energy for muscle movement. Myos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ATPase
ATPases (, Adenosine 5'-TriPhosphatase, adenylpyrophosphatase, ATP monophosphatase, triphosphatase, SV40 T-antigen, ATP hydrolase, complex V (mitochondrial electron transport), (Ca2+ + Mg2+)-ATPase, HCO3−-ATPase, adenosine triphosphatase) are a class of enzymes that catalyze the decomposition of ATP into ADP and a free phosphate ion or the inverse reaction. This dephosphorylation reaction releases energy, which the enzyme (in most cases) harnesses to drive other chemical reactions that would not otherwise occur. This process is widely used in all known forms of life. Some such enzymes are integral membrane proteins (anchored within biological membranes), and move solutes across the membrane, typically against their concentration gradient. These are called transmembrane ATPases. Functions Transmembrane ATPases import metabolites necessary for cell metabolism and export toxins, wastes, and solutes that can hinder cellular processes. An important example is the sodium-potass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Microscopy
An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination. As the wavelength of an electron can be up to 100,000 times shorter than that of visible light photons, electron microscopes have a higher resolving power than light microscopes and can reveal the structure of smaller objects. A scanning transmission electron microscope has achieved better than 50 pm resolution in annular dark-field imaging mode and magnifications of up to about 10,000,000× whereas most light microscopes are limited by diffraction to about 200 nm resolution and useful magnifications below 2000×. Electron microscopes use shaped magnetic fields to form electron optical lens systems that are analogous to the glass lenses of an optical light microscope. Electron microscopes are used to investigate the ultrastructure of a wide range of biological and inorganic specimens including microorganisms, cells, large molecules, biopsy samples, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarcomere
A sarcomere (Greek σάρξ ''sarx'' "flesh", μέρος ''meros'' "part") is the smallest functional unit of striated muscle tissue. It is the repeating unit between two Z-lines. Skeletal muscles are composed of tubular muscle cells (called muscle fibers or myofibers) which are formed during embryonic myogenesis. Muscle fibers contain numerous tubular myofibrils. Myofibrils are composed of repeating sections of sarcomeres, which appear under the microscope as alternating dark and light bands. Sarcomeres are composed of long, fibrous proteins as filaments that slide past each other when a muscle contracts or relaxes. The costamere is a different component that connects the sarcomere to the sarcolemma. Two of the important proteins are myosin, which forms the thick filament, and actin, which forms the thin filament. Myosin has a long, fibrous tail and a globular head, which binds to actin. The myosin head also binds to ATP, which is the source of energy for muscle movement. Myos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-ray Diffraction
X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles and intensities of these diffracted beams, a crystallographer can produce a three-dimensional picture of the density of electrons within the crystal. From this electron density, the mean positions of the atoms in the crystal can be determined, as well as their chemical bonds, their crystallographic disorder, and various other information. Since many materials can form crystals—such as salts, metals, minerals, semiconductors, as well as various inorganic, organic, and biological molecules—X-ray crystallography has been fundamental in the development of many scientific fields. In its first decades of use, this method determined the size of atoms, the lengths and types of chemical bonds, and the atomic-scale differences among various mat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
King's College London
King's College London (informally King's or KCL) is a public research university located in London, England. King's was established by royal charter in 1829 under the patronage of King George IV and the Duke of Wellington. In 1836, King's became one of the two founding colleges of the University of London. It is one of the oldest university-level institutions in England. In the late 20th century, King's grew through a series of mergers, including with Queen Elizabeth College and Chelsea College of Science and Technology (in 1985), the Institute of Psychiatry (in 1997), the United Medical and Dental Schools of Guy's and St Thomas' Hospitals and the Florence Nightingale School of Nursing and Midwifery (in 1998). King's has five campuses: its historic Strand Campus in central London, three other Thames-side campuses (Guy's, St Thomas' and Waterloo) nearby and one in Denmark Hill in south London. It also has a presence in Shrivenham, Oxfordshire, for its professional mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Francis O
Francis may refer to: People *Pope Francis, the head of the Catholic Church and sovereign of the Vatican City State and Bishop of Rome *Francis (given name), including a list of people and fictional characters *Francis (surname) Places * Rural Municipality of Francis No. 127, Saskatchewan, Canada * Francis, Saskatchewan, Canada **Francis (electoral district) *Francis, Nebraska *Francis Township, Holt County, Nebraska * Francis, Oklahoma *Francis, Utah Other uses * ''Francis'' (film), the first of a series of comedies featuring Francis the Talking Mule, voiced by Chill Wills *''Francis'', a 1983 play by Julian Mitchell *FRANCIS, a bibliographic database * ''Francis'' (1793), a colonial schooner in Australia *Francis turbine, a type of water turbine *Francis (band), a Sweden-based folk band * Francis, a character played by YouTuber Boogie2988 See also *Saint Francis (other) *Francies, a surname, including a list of people with the name *Francisco (other) *Francis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archibald Hill
Archibald Vivian Hill (26 September 1886 – 3 June 1977), known as A. V. Hill, was a British physiologist, one of the founders of the diverse disciplines of biophysics and operations research. He shared the 1922 Nobel Prize in Physiology or Medicine for his elucidation of the production of heat and mechanical work in muscles. Biography Born in Bristol, he was educated at Blundell's School and graduated from Trinity College, Cambridge as third wrangler in the mathematics tripos before turning to physiology. While still an undergraduate at Trinity College, he derived in 1909 what came to be known as the Langmuir equation. This is closely related to Michaelis-Menten kinetics. In this paper, Hill's first publication, he derived both the equilibrium form of the Langmuir equation, and also the exponential approach to equilibrium. The paper, written under the supervision of John Newport Langley, is a landmark in the history of receptor theory, because the context for the derivatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otto Fritz Meyerhof
Otto Fritz Meyerhof (; April 12, 1884 – October 6, 1951) was a German physician and biochemist who won the 1922 Nobel Prize in Physiology and Medicine. Biography Otto Fritz Meyerhof was born in Hannover, at Theaterplatz 16A (now:Rathenaustrasse 16A), the son of wealthy Jewish parents. In 1888, his family moved to Berlin, where Otto spent most of his childhood, and where he started his study of medicine. He continued these studies in Strasbourg and Heidelberg, from which he graduated in 1909, with a work titled "Contributions to the Psychological Theory of Mental Illness". In Heidelberg, he met Hedwig Schallenberg. They married in 1914 and became parents of a daughter, Bettina, and two sons, Gottfried (who referred, after emigration, to himself as Geoffrey) as well as Walter. In 1912, Otto Meyerhof moved to the University of Kiel, where he received a professorship in 1918. In 1922, he was awarded the Nobel Prize in Medicine, with Archibald Vivian Hill, for his work on muscle me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brunó Ferenc Straub
Brunó Ferenc Straub (5 January 1914 in Nagyvárad, Austria-Hungary (now Oradea, Romania) – 15 February 1996) was a biochemist. As a young scholar he was a research assistant of Albert Szent-Györgyi at the University of Szeged, and subsequently worked at the Molteno Institute, Cambridge, UK. He is credited with the discovery of actin. He founded the Biological Research Centre in Szeged. He was the chairman of the Hungarian Presidential Council from 29 June 1988 to 23 October 1989. He proposed the theory of conformational selection in 1964; the same year the MWC model In biochemistry, the Monod-Wyman-Changeux model (MWC model, also known as the symmetry model) describes allosteric transitions of proteins made up of identical subunits. It was proposed by Jean-Pierre Changeux in his PhD thesis, and described by ... was proposed. External links {{DEFAULTSORT:Straub, Bruno Ferenc 1914 births 1996 deaths People from Oradea Members of the National Assembly of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fumaric Acid
Fumaric acid is an organic compound with the formula HO2CCH=CHCO2H. A white solid, fumaric acid occurs widely in nature. It has a fruit-like taste and has been used as a food additive. Its E number is E297. The salts and esters are known as fumarates. Fumarate can also refer to the ion (in solution). Fumaric acid is the trans isomer of butenedioic acid, while maleic acid is the cis isomer. Biosynthesis and occurrence It is produced in eukaryotic organisms from succinate in complex 2 of the electron transport chain via the enzyme succinate dehydrogenase. It is one of two isomeric unsaturated dicarboxylic acids, the other being maleic acid. In fumaric acid the carboxylic acid groups are ''trans'' (''E'') and in maleic acid they are ''cis'' (''Z''). Fumaric acid is found in fumitory (''Fumaria officinalis''), bolete mushrooms (specifically ''Boletus fomentarius var. pseudo-igniarius''), lichen, and Iceland moss. Fumarate is an intermediate in the citric acid cycle used b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitamin C
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) and wrinkles on the face. It is used to prevent and treat scurvy. Vitamin C is an essential nutrient involved in the repair of tissue, the formation of collagen, and the enzymatic production of certain neurotransmitters. It is required for the functioning of several enzymes and is important for immune system function. It also functions as an antioxidant. Most animals are able to synthesize their own vitamin C. However, apes (including humans) and monkeys (but not all primates), most bats, some rodents, and certain other animals must acquire it from dietary sources. There is some evidence that regular use of supplements may reduce the duration of the common cold, but it does not appear to prevent infection. It is unclear whether supple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
