CarbohydrateA carbohydrate (ˌkɑːrboʊˈhaɪdreɪt) is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where m may or may not be different from n), which does not mean the H has covalent bonds with O (for example with , H has a covalent bond with C but not with O). However, not all carbohydrates conform to this precise stoichiometric definition (e.g.
GlucoseGlucose is a sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using energy from sunlight, where it is used to make cellulose in cell walls, the most abundant carbohydrate in the world. In energy metabolism, glucose is the most important source of energy in all organisms. Glucose for metabolism is stored as a polymer, in plants mainly as starch and amylopectin, and in animals as glycogen.
GalactoseGalactose (gəˈlæktoʊs, galacto- + -ose, "milk sugar"), sometimes abbreviated Gal, is a monosaccharide sugar that is about as sweet as glucose, and about 65% as sweet as sucrose. It is an aldohexose and a C-4 epimer of glucose. A galactose molecule linked with a glucose molecule forms a lactose molecule. Galactan is a polymeric form of galactose found in hemicellulose, and forming the core of the galactans, a class of natural polymeric carbohydrates.
AnomerIn carbohydrate chemistry, a pair of anomers () is a pair of near-identical stereoisomers or diastereomers that differ at only the anomeric carbon, the carbon that bears the aldehyde or ketone functional group in the sugar's open-chain form. However, in order for anomers to exist, the sugar must be in its cyclic form, since in open-chain form, the anomeric carbon is planar and thus achiral. More formally stated, then, an anomer is an epimer at the hemiacetal/hemiketal carbon in a cyclic saccharide.
Reducing sugarA reducing sugar is any sugar that is capable of acting as a reducing agent. In an alkaline solution, a reducing sugar forms some aldehyde or ketone, which allows it to act as a reducing agent, for example in Benedict's reagent. In such a reaction, the sugar becomes a carboxylic acid. All monosaccharides are reducing sugars, along with some disaccharides, some oligosaccharides, and some polysaccharides. The monosaccharides can be divided into two groups: the aldoses, which have an aldehyde group, and the ketoses, which have a ketone group.
MonosaccharideMonosaccharides (from Greek monos: single, sacchar: sugar), also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built. They are usually colorless, water-soluble, and crystalline solids. Contrary to their name (sugars), only some monosaccharides have a sweet taste. Most monosaccharides have the formula (CH2O) (though not all molecules with this formula are monosaccharides). Examples of monosaccharides include glucose (dextrose), fructose (levulose), and galactose.
Keratan sulfateKeratan sulfate (KS), also called keratosulfate, is any of several sulfated glycosaminoglycans (structural carbohydrates) that have been found especially in the cornea, cartilage, and bone. It is also synthesized in the central nervous system where it participates both in development and in the glial scar formation following an injury. Keratan sulfates are large, highly hydrated molecules which in joints can act as a cushion to absorb mechanical shock.
FructoseFructose ('frVktous,_-ouz), or fruit sugar, is a ketonic simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed by the gut directly into the blood of the portal vein during digestion. The liver then converts both fructose and galactose into glucose, so that dissolved glucose, known as blood sugar, is the only monosaccharide present in circulating blood.
Hyaluronic acidHyaluronic acid (ˌhaɪ.əljʊəˈrɒnɪk; abbreviated HA; conjugate base hyaluronate), also called hyaluronan, is an anionic, nonsulfated glycosaminoglycan distributed widely throughout connective, epithelial, and neural tissues. It is unique among glycosaminoglycans as it is non-sulfated, forms in the plasma membrane instead of the Golgi apparatus, and can be very large: human synovial HA averages about 7 million Da per molecule, or about 20,000 disaccharide monomers, while other sources mention 3–4 million Da.
ProteoglycanProteoglycans are proteins that are heavily glycosylated. The basic proteoglycan unit consists of a "core protein" with one or more covalently attached glycosaminoglycan (GAG) chain(s). The point of attachment is a serine (Ser) residue to which the glycosaminoglycan is joined through a tetrasaccharide bridge (e.g. chondroitin sulfate-GlcA-Gal-Gal-Xyl-PROTEIN). The Ser residue is generally in the sequence -Ser-Gly-X-Gly- (where X can be any amino acid residue but proline), although not every protein with this sequence has an attached glycosaminoglycan.
CharcoalCharcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, called charcoal burning, often by forming a charcoal kiln, the heat is supplied by burning part of the starting material itself, with a limited supply of oxygen. The material can also be heated in a closed retort. Modern "charcoal" briquettes used for outdoor cooking may contain many other additives, e.
N-linked glycosylationN-linked glycosylation, is the attachment of an oligosaccharide, a carbohydrate consisting of several sugar molecules, sometimes also referred to as glycan, to a nitrogen atom (the amide nitrogen of an asparagine (Asn) residue of a protein), in a process called N-glycosylation, studied in biochemistry. The resulting protein is called an N-linked glycan, or simply an N-glycan. This type of linkage is important for both the structure and function of many eukaryotic proteins.
Enantioselective synthesisEnantioselective synthesis, also called asymmetric synthesis, is a form of chemical synthesis. It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of chirality are formed in a substrate molecule and which produces the stereoisomeric (enantiomeric or diastereomeric) products in unequal amounts." Put more simply: it is the synthesis of a compound by a method that favors the formation of a specific enantiomer or diastereomer.
GlycosaminoglycanGlycosaminoglycans (GAGs) or mucopolysaccharides are long, linear polysaccharides consisting of repeating disaccharide units (i.e. two-sugar units). The repeating two-sugar unit consists of a uronic sugar and an amino sugar, except in the case of the sulfated glycosaminoglycan keratan, where, in place of the uronic sugar there is a galactose unit. GAGs are found in vertebrates, invertebrates and bacteria. Because GAGs are highly polar molecules and attract water; the body uses them as lubricants or shock absorbers.
CatalysisCatalysis (kəˈtæləsɪs) is the process of change in rate of a chemical reaction by adding a substance known as a catalyst (ˈkætəlɪst). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst.
Dynamic linkerIn computing, a dynamic linker is the part of an operating system that loads and links the shared libraries needed by an executable when it is executed (at "run time"), by copying the content of libraries from persistent storage to RAM, filling jump tables and relocating pointers. The specific operating system and executable format determine how the dynamic linker functions and how it is implemented.
Protected areaProtected areas or conservation areas are locations which receive protection because of their recognized natural, ecological or cultural values. Protected areas are those areas in which human presence or the exploitation of natural resources (e.g. firewood, non-timber forest products, water, ...) is limited. The term "protected area" also includes marine protected areas and transboundary protected areas across multiple borders. As of 2016, there are over 161,000 protected areas representing about 17 percent of the world's land surface area (excluding Antarctica).
Linker (computing)In computing, a linker or link editor is a computer system program that takes one or more s (generated by a compiler or an assembler) and combines them into a single executable file, library file, or another "object" file. A simpler version that writes its output directly to memory is called the loader, though loading is typically considered a separate process. Computer programs typically are composed of several parts or modules; these parts/modules do not need to be contained within a single , and in such cases refer to each other by means of symbols as addresses into other modules, which are mapped into memory addresses when linked for execution.
Heterogeneous catalysisHeterogeneous catalysis is catalysis where the phase of catalysts differs from that of the reactants or products. The process contrasts with homogeneous catalysis where the reactants, products and catalyst exist in the same phase. Phase distinguishes between not only solid, liquid, and gas components, but also immiscible mixtures (e.g. oil and water), or anywhere an interface is present. Heterogeneous catalysis typically involves solid phase catalysts and gas phase reactants.
States' rightsIn American political discourse, states' rights are political powers held for the state governments rather than the federal government according to the United States Constitution, reflecting especially the enumerated powers of Congress and the Tenth Amendment. The enumerated powers that are listed in the Constitution include exclusive federal powers, as well as concurrent powers that are shared with the states, and all of those powers are contrasted with the reserved powers—also called states' rights—that only the states possess.
