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Glucopyranose
Glucose is a sugar with the molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using energy from sunlight. It is used by plants to make cellulose, the most abundant carbohydrate in the world, for use in cell walls, and by all living organisms to make adenosine triphosphate (ATP), which is used by the cell as energy. 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 amylose and amylopectin, and in animals as glycogen. Glucose circulates in the blood of animals as blood sugar. The naturally occurring form is -glucose, while its stereoisomer -glucose is produced synthetically in comparatively small amounts and is less biologically active. Glucose is a monosaccharide containing six carbon atoms and an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbohydrate
A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' may differ). This formula does not imply direct covalent bonding between hydrogen and oxygen atoms; for example, in , hydrogen is covalently bonded to carbon, not oxygen. While the 2:1 hydrogen-to-oxygen ratio is characteristic of many carbohydrates, exceptions exist. For instance, uronic acids and deoxy-sugars like fucose deviate from this precise stoichiometric definition. Conversely, some compounds conforming to this definition, such as formaldehyde and acetic acid, are not classified as carbohydrates. The term is predominantly used in biochemistry, functioning as a synonym for saccharide (), a group that includes sugars, starch, and cellulose. The saccharides are divided into four chemical groups: monosaccharides, disaccharides, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haworth Projection
In chemistry, a Haworth projection is a common way of writing a structural formula to represent the cyclic structure of monosaccharides with a simple three-dimensional perspective. A Haworth projection approximates the shapes of the actual molecules better for furanoses—which are in reality nearly planar—than for pyranoses that exist in solution in the chair conformation. Organic chemistry and especially biochemistry are the areas of chemistry that use the Haworth projection the most. The Haworth projection was named after the British chemist Sir Norman Haworth. A Haworth projection has the following characteristics: * Carbon is the implicit type of atom. In the example on the right, the atoms numbered from 1 to 6 are all carbon atoms. Carbon 1 is known as the anomeric carbon. * Hydrogen atoms on carbon are implicit. In the example, atoms 1 to 6 have extra hydrogen atoms not depicted. * A thicker line indicates atoms that are closer to the observer. In the example on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monosaccharide
Monosaccharides (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. Chemically, monosaccharides are polyhydroxy aldehydes with the formula or polyhydroxy ketones with the formula with three or more carbon atoms. They are usually colorless, water- soluble, and crystalline organic solids. Contrary to their name (sugars), only some monosaccharides have a sweet taste. Most monosaccharides have the formula (CH2O)''x'' (though not all molecules with this formula are monosaccharides). Examples of monosaccharides include glucose (dextrose), fructose (levulose), and galactose. Monosaccharides are the building blocks of disaccharides (such as sucrose, lactose and maltose) and polysaccharides (such as cellulose and starch). The table sugar used in everyday vernacular is itself a disaccharide sucrose comprising one molecule of each of the two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldehyde
In organic chemistry, an aldehyde () (lat. ''al''cohol ''dehyd''rogenatum, dehydrogenated alcohol) is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl group. Aldehydes are a common motif in many chemicals important in technology and biology. Structure and bonding Aldehyde molecules have a central carbon atom that is connected by a double bond to oxygen, a single bond to hydrogen and another single bond to a third substituent, which is carbon or, in the case of formaldehyde, hydrogen. The central carbon is often described as being sp2- hybridized. The aldehyde group is somewhat polar. The bond length is about 120–122 picometers. Physical properties and characterization Aldehydes have properties that are diverse and that depend on the remainder of the molecule. Smaller aldehydes such as formaldehyde and acetaldehyde are solubl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldohexose
In chemistry, a hexose is a monosaccharide (simple sugar) with six carbon atoms. The chemical formula for all hexoses is , and their molecular weight is 180.156 g/mol. Hexoses exist in two forms, open-chain or cyclic, that easily convert into each other in aqueous solutions. The open-chain form of a hexose, which usually is favored in solutions, has the general structure , where ''n'' is 1, 2, 3, 4, 5. Namely, five of the carbons have one hydroxyl functional group () each, connected by a single bond, and one has an oxo group (), forming a carbonyl group (). The remaining bonds of the carbon atoms are satisfied by seven hydrogen atoms. The carbons are commonly numbered 1 to 6 starting at the end closest to the carbonyl. Hexoses are extremely important in biochemistry, both as isolated molecules (such as glucose and fructose) and as building blocks of other compounds such as starch, cellulose, and glycosides. Hexoses can form dihexose (like sucrose) by a condensation reacti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycogen
Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, fungi, and bacteria. It is the main storage form of glucose in the human body. Glycogen functions as one of three regularly used forms of energy reserves, creatine phosphate being for very short-term, glycogen being for short-term and the triglyceride stores in adipose tissue (i.e., body fat) being for long-term storage. Protein, broken down into amino acids, is seldom used as a main energy source except during starvation and glycolytic crisis ''(see bioenergetic systems)''. In humans, glycogen is made and stored primarily in the cells of the liver and skeletal muscle. In the liver, glycogen can make up 5–6% of the organ's fresh weight: the liver of an adult, weighing 1.5 kg, can store roughly 100–120 grams of glycogen. In skeletal muscle, glycogen is found in a low concentration (1–2% of the muscle mass): the skeletal muscle of an adult weighing 70 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood Sugar
The blood sugar level, blood sugar concentration, blood glucose level, or glycemia is the measure of glucose concentrated in the blood. The body tightly regulates blood glucose levels as a part of metabolic homeostasis. For a 70 kg (154 lb) human, approximately four grams of dissolved glucose (also called "blood glucose") is maintained in the blood plasma at all times. Glucose that is not circulating in the blood is stored in skeletal muscle and liver cells in the form of glycogen; in fasting individuals, blood glucose is maintained at a constant level by releasing just enough glucose from these glycogen stores in the liver and skeletal muscle in order to maintain homeostasis. Glucose can be transported from the intestines or liver to other tissues in the body via the bloodstream. Cellular glucose uptake is primarily regulated by insulin, a hormone produced in the pancreas. Once inside the cell, the glucose can now act as an energy source as it undergoes the pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereoisomerism
In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in space. This contrasts with structural isomers, which share the same molecular formula, but the bond connections or their order differs. By definition, molecules that are stereoisomers of each other represent the same structural isomer. Enantiomers Enantiomers, also known as optical isomers, are two stereoisomers that are related to each other by a reflection: they are mirror images of each other that are non-superposable. Human hands are a macroscopic analog of this. Every stereogenic center in one has the opposite configuration in the other. Two compounds that are enantiomers of each other have the same physical properties, except for the direction in which they rotate polarized light and how they interact with different enantiomers of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skeletal Formula
The skeletal formula, line-angle formula, bond-line formula or shorthand formula of an organic compound is a type of minimalist structural formula representing a molecule's Atom, atoms, structural isomer, bonds and some details of its molecular geometry, geometry. The lines in a skeletal formula represent bonds between carbon atoms, unless labelled with another element. Labels are optional for carbon atoms, and the hydrogen atoms attached to them. An early form of this representation was first developed by organic chemist August Kekulé, while the modern form is closely related to and influenced by the Lewis structure of molecules and their valence electrons. Hence they are sometimes termed Kekulé structures or Lewis–Kekulé structures. Skeletal formulas have become ubiquitous in organic chemistry, partly because they are relatively quick and simple to draw, and also because the Arrow pushing, curved arrow notation used for discussions of reaction mechanisms and Resonance ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycogenolysis
Glycogenolysis is the breakdown of glycogen (n) to glucose-1-phosphate and glycogen (n-1). Glycogen branches are catabolized by the sequential removal of glucose monomers via phosphorolysis, by the enzyme glycogen phosphorylase. Mechanism In the muscles, glycogenolysis begins due to the binding of cAMP to phosphorylate kinase, converting the latter to its active form so it can convert phosphorylase b to phosphorylase a, which is responsible for catalyzing the breakdown of glycogen. The overall reaction for the breakdown of glycogen to glucose-1-phosphate is: : glycogen(n residues) + Pi glycogen(n-1 residues) + glucose-1-phosphate Here, glycogen phosphorylase cleaves the bond linking a terminal glucose residue to a glycogen branch by substitution of a phosphoryl group for the α →4linkage. Glucose-1-phosphate is converted to glucose-6-phosphate (which often ends up in glycolysis) by the enzyme phosphoglucomutase. Glucose residues are phosphorolysed from bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amylopectin
Amylopectin is a water-insoluble polysaccharide and highly branched polymer of α-glucose units found in plants. It is one of the two components of starch, the other being amylose. Plants store starch within specialized organelles called amyloplasts. To generate energy, the plant hydrolyzes the starch, releasing the glucose subunits. Humans and other animals that eat plant foods also use amylase, an enzyme that assists in breaking down amylopectin, to initiate the hydrolysis of starch. Starch is made of about 70–80% amylopectin by weight, though it varies depending on the source. For example, it ranges from lower percent content in long-grain rice, amylomaize, and Russet Burbank potato, russet potatoes to 100% in glutinous rice, waxy potato starch, and waxy corn. Amylopectin is highly branched, being formed of 2,000 to 200,000 glucose units. Its inner chains are formed of 20–24 glucose subunits. Starch gelatinization, Dissolved amylopectin starch has a lower tendency of retrog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
