1.
Jmol
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Jmol is computer software for molecular modelling chemical structures in 3-dimensions. Jmol returns a 3D representation of a molecule that may be used as a teaching tool and it is written in the programming language Java, so it can run on the operating systems Windows, macOS, Linux, and Unix, if Java is installed. It is free and open-source software released under a GNU Lesser General Public License version 2.0, a standalone application and a software development kit exist that can be integrated into other Java applications, such as Bioclipse and Taverna. A popular feature is an applet that can be integrated into web pages to display molecules in a variety of ways, for example, molecules can be displayed as ball-and-stick models, space-filling models, ribbon diagrams, etc. Jmol supports a range of chemical file formats, including Protein Data Bank, Crystallographic Information File, MDL Molfile. There is also a JavaScript-only version, JSmol, that can be used on computers with no Java, the Jmol applet, among other abilities, offers an alternative to the Chime plug-in, which is no longer under active development. While Jmol has many features that Chime lacks, it does not claim to reproduce all Chime functions, most notably, Chime requires plug-in installation and Internet Explorer 6.0 or Firefox 2.0 on Microsoft Windows, or Netscape Communicator 4.8 on Mac OS9. Jmol requires Java installation and operates on a variety of platforms. For example, Jmol is fully functional in Mozilla Firefox, Internet Explorer, Opera, Google Chrome, fast and Scriptable Molecular Graphics in Web Browsers without Java3D
2.
ChemSpider
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ChemSpider is a database of chemicals. ChemSpider is owned by the Royal Society of Chemistry, the database contains information on more than 50 million molecules from over 500 data sources including, Each chemical is given a unique identifier, which forms part of a corresponding URL. This is an approach to develop an online chemistry database. The search can be used to widen or restrict already found results, structure searching on mobile devices can be done using free apps for iOS and for the Android. The ChemSpider database has been used in combination with text mining as the basis of document markup. The result is a system between chemistry documents and information look-up via ChemSpider into over 150 data sources. ChemSpider was acquired by the Royal Society of Chemistry in May,2009, prior to the acquisition by RSC, ChemSpider was controlled by a private corporation, ChemZoo Inc. The system was first launched in March 2007 in a release form. ChemSpider has expanded the generic support of a database to include support of the Wikipedia chemical structure collection via their WiChempedia implementation. A number of services are available online. SyntheticPages is an interactive database of synthetic chemistry procedures operated by the Royal Society of Chemistry. Users submit synthetic procedures which they have conducted themselves for publication on the site and these procedures may be original works, but they are more often based on literature reactions. Citations to the published procedure are made where appropriate. They are checked by an editor before posting. The pages do not undergo formal peer-review like a journal article. The comments are moderated by scientific editors. The intention is to collect practical experience of how to conduct useful chemical synthesis in the lab, while experimental methods published in an ordinary academic journal are listed formally and concisely, the procedures in ChemSpider SyntheticPages are given with more practical detail. Comments by submitters are included as well, other publications with comparable amounts of detail include Organic Syntheses and Inorganic Syntheses
3.
PubChem
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PubChem is a database of chemical molecules and their activities against biological assays. The system is maintained by the National Center for Biotechnology Information, a component of the National Library of Medicine, PubChem can be accessed for free through a web user interface. Millions of compound structures and descriptive datasets can be downloaded via FTP. PubChem contains substance descriptions and small molecules with fewer than 1000 atoms and 1000 bonds, more than 80 database vendors contribute to the growing PubChem database. PubChem consists of three dynamically growing primary databases, as of 28 January 2016, Compounds,82.6 million entries, contains pure and characterized chemical compounds. Substances,198 million entries, contains also mixtures, extracts, complexes, bioAssay, bioactivity results from 1.1 million high-throughput screening programs with several million values. PubChem contains its own online molecule editor with SMILES/SMARTS and InChI support that allows the import and export of all common chemical file formats to search for structures and fragments. In the text search form the database fields can be searched by adding the name in square brackets to the search term. A numeric range is represented by two separated by a colon. The search terms and field names are case-insensitive, parentheses and the logical operators AND, OR, and NOT can be used. AND is assumed if no operator is used, example,0,5000,50,10 -5,5 PubChem was released in 2004. The American Chemical Society has raised concerns about the publicly supported PubChem database and they have a strong interest in the issue since the Chemical Abstracts Service generates a large percentage of the societys revenue. To advocate their position against the PubChem database, ACS has actively lobbied the US Congress, soon after PubChems creation, the American Chemical Society lobbied U. S. Congress to restrict the operation of PubChem, which they asserted competes with their Chemical Abstracts Service
4.
International Chemical Identifier
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Initially developed by IUPAC and NIST from 2000 to 2005, the format and algorithms are non-proprietary. The continuing development of the standard has supported since 2010 by the not-for-profit InChI Trust. The current version is 1.04 and was released in September 2011, prior to 1.04, the software was freely available under the open source LGPL license, but it now uses a custom license called IUPAC-InChI Trust License. Not all layers have to be provided, for instance, the layer can be omitted if that type of information is not relevant to the particular application. InChIs can thus be seen as akin to a general and extremely formalized version of IUPAC names and they can express more information than the simpler SMILES notation and differ in that every structure has a unique InChI string, which is important in database applications. Information about the 3-dimensional coordinates of atoms is not represented in InChI, the InChI algorithm converts input structural information into a unique InChI identifier in a three-step process, normalization, canonicalization, and serialization. The InChIKey, sometimes referred to as a hashed InChI, is a fixed length condensed digital representation of the InChI that is not human-understandable. The InChIKey specification was released in September 2007 in order to facilitate web searches for chemical compounds and it should be noted that, unlike the InChI, the InChIKey is not unique, though collisions can be calculated to be very rare, they happen. In January 2009 the final 1.02 version of the InChI software was released and this provided a means to generate so called standard InChI, which does not allow for user selectable options in dealing with the stereochemistry and tautomeric layers of the InChI string. The standard InChIKey is then the hashed version of the standard InChI string, the standard InChI will simplify comparison of InChI strings and keys generated by different groups, and subsequently accessed via diverse sources such as databases and web resources. Every InChI starts with the string InChI= followed by the version number and this is followed by the letter S for standard InChIs. The remaining information is structured as a sequence of layers and sub-layers, the layers and sub-layers are separated by the delimiter / and start with a characteristic prefix letter. The six layers with important sublayers are, Main layer Chemical formula and this is the only sublayer that must occur in every InChI. The atoms in the formula are numbered in sequence, this sublayer describes which atoms are connected by bonds to which other ones. Describes how many hydrogen atoms are connected to each of the other atoms, the condensed,27 character standard InChIKey is a hashed version of the full standard InChI, designed to allow for easy web searches of chemical compounds. Most chemical structures on the Web up to 2007 have been represented as GIF files, the full InChI turned out to be too lengthy for easy searching, and therefore the InChIKey was developed. With all databases currently having below 50 million structures, such duplication appears unlikely at present, a recent study more extensively studies the collision rate finding that the experimental collision rate is in agreement with the theoretical expectations. Example, Morphine has the structure shown on the right, as the InChI cannot be reconstructed from the InChIKey, an InChIKey always needs to be linked to the original InChI to get back to the original structure
5.
Simplified molecular-input line-entry system
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The simplified molecular-input line-entry system is a specification in form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules, the original SMILES specification was initiated in the 1980s. It has since modified and extended. In 2007, a standard called OpenSMILES was developed in the open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, the original SMILES specification was initiated by David Weininger at the USEPA Mid-Continent Ecology Division Laboratory in Duluth in the 1980s. The Environmental Protection Agency funded the project to develop SMILES. It has since modified and extended by others, most notably by Daylight Chemical Information Systems. In 2007, a standard called OpenSMILES was developed by the Blue Obelisk open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, in July 2006, the IUPAC introduced the InChI as a standard for formula representation. SMILES is generally considered to have the advantage of being slightly more human-readable than InChI, the term SMILES refers to a line notation for encoding molecular structures and specific instances should strictly be called SMILES strings. However, the term SMILES is also used to refer to both a single SMILES string and a number of SMILES strings, the exact meaning is usually apparent from the context. The terms canonical and isomeric can lead to confusion when applied to SMILES. The terms describe different attributes of SMILES strings and are not mutually exclusive, typically, a number of equally valid SMILES strings can be written for a molecule. For example, CCO, OCC and CC all specify the structure of ethanol, algorithms have been developed to generate the same SMILES string for a given molecule, of the many possible strings, these algorithms choose only one of them. This SMILES is unique for each structure, although dependent on the algorithm used to generate it. These algorithms first convert the SMILES to a representation of the molecular structure. A common application of canonical SMILES is indexing and ensuring uniqueness of molecules in a database, there is currently no systematic comparison across commercial software to test if such flaws exist in those packages. SMILES notation allows the specification of configuration at tetrahedral centers, and these are structural features that cannot be specified by connectivity alone and SMILES which encode this information are termed isomeric SMILES
6.
Chemical formula
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These are limited to a single typographic line of symbols, which may include subscripts and superscripts. A chemical formula is not a name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulas can fully specify the structure of only the simplest of molecules and chemical substances, the simplest types of chemical formulas are called empirical formulas, which use letters and numbers indicating the numerical proportions of atoms of each type. Molecular formulas indicate the numbers of each type of atom in a molecule. For example, the formula for glucose is CH2O, while its molecular formula is C6H12O6. This is possible if the relevant bonding is easy to show in one dimension, an example is the condensed molecular/chemical formula for ethanol, which is CH3-CH2-OH or CH3CH2OH. For reasons of structural complexity, there is no condensed chemical formula that specifies glucose, chemical formulas may be used in chemical equations to describe chemical reactions and other chemical transformations, such as the dissolving of ionic compounds into solution. A chemical formula identifies each constituent element by its chemical symbol, in empirical formulas, these proportions begin with a key element and then assign numbers of atoms of the other elements in the compound, as ratios to the key element. For molecular compounds, these numbers can all be expressed as whole numbers. For example, the formula of ethanol may be written C2H6O because the molecules of ethanol all contain two carbon atoms, six hydrogen atoms, and one oxygen atom. Some types of compounds, however, cannot be written with entirely whole-number empirical formulas. An example is boron carbide, whose formula of CBn is a variable non-whole number ratio with n ranging from over 4 to more than 6.5. When the chemical compound of the consists of simple molecules. These types of formulas are known as molecular formulas and condensed formulas. A molecular formula enumerates the number of atoms to reflect those in the molecule, so that the formula for glucose is C6H12O6 rather than the glucose empirical formula. However, except for very simple substances, molecular chemical formulas lack needed structural information, for simple molecules, a condensed formula is a type of chemical formula that may fully imply a correct structural formula. For example, ethanol may be represented by the chemical formula CH3CH2OH
7.
Chemical compound
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A chemical compound is an entity consisting of two or more atoms, at least two from different elements, which associate via chemical bonds. Many chemical compounds have a numerical identifier assigned by the Chemical Abstracts Service. For example, water is composed of two atoms bonded to one oxygen atom, the chemical formula is H2O. A compound can be converted to a different chemical composition by interaction with a chemical compound via a chemical reaction. In this process, bonds between atoms are broken in both of the compounds, and then bonds are reformed so that new associations are made between atoms. Schematically, this reaction could be described as AB + CD → AC + BD, where A, B, C, and D are each unique atoms, and AB, CD, AC, and BD are each unique compounds. A chemical element bonded to a chemical element is not a chemical compound since only one element. Examples are the diatomic hydrogen and the polyatomic molecule sulfur. Chemical compounds have a unique and defined chemical structure held together in a spatial arrangement by chemical bonds. Pure chemical elements are not considered chemical compounds, failing the two or more atom requirement, though they often consist of molecules composed of multiple atoms. There is varying and sometimes inconsistent nomenclature differentiating substances, which include truly non-stoichiometric examples, from chemical compounds, other compounds regarded as chemically identical may have varying amounts of heavy or light isotopes of the constituent elements, which changes the ratio of elements by mass slightly. Characteristic properties of compounds include that elements in a compound are present in a definite proportion, for example, the molecule of the compound water is composed of hydrogen and oxygen in a ratio of 2,1. In addition, compounds have a set of properties. The physical and chemical properties of compounds differ from those of their constituent elements, however, mixtures can be created by mechanical means alone, but a compound can be created only by a chemical reaction. Some mixtures are so combined that they have some properties similar to compounds. Other examples of compound-like mixtures include intermetallic compounds and solutions of metals in a liquid form of ammonia. Compounds may be described using formulas in various formats, for compounds that exist as molecules, the formula for the molecular unit is shown. For polymeric materials, such as minerals and many metal oxides, the elements in a chemical formula are normally listed in a specific order, called the Hill system
8.
Carbon
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Carbon is a chemical element with symbol C and atomic number 6. It is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds, three isotopes occur naturally, 12C and 13C being stable, while 14C is a radioactive isotope, decaying with a half-life of about 5,730 years. Carbon is one of the few elements known since antiquity, Carbon is the 15th most abundant element in the Earths crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. It is the second most abundant element in the body by mass after oxygen. The atoms of carbon can bond together in different ways, termed allotropes of carbon, the best known are graphite, diamond, and amorphous carbon. The physical properties of carbon vary widely with the allotropic form, for example, graphite is opaque and black while diamond is highly transparent. Graphite is soft enough to form a streak on paper, while diamond is the hardest naturally occurring material known, graphite is a good electrical conductor while diamond has a low electrical conductivity. Under normal conditions, diamond, carbon nanotubes, and graphene have the highest thermal conductivities of all known materials, all carbon allotropes are solids under normal conditions, with graphite being the most thermodynamically stable form. They are chemically resistant and require high temperature to react even with oxygen, the most common oxidation state of carbon in inorganic compounds is +4, while +2 is found in carbon monoxide and transition metal carbonyl complexes. The largest sources of carbon are limestones, dolomites and carbon dioxide, but significant quantities occur in organic deposits of coal, peat, oil. For this reason, carbon has often referred to as the king of the elements. The allotropes of carbon graphite, one of the softest known substances, and diamond. It bonds readily with other small atoms including other carbon atoms, Carbon is known to form almost ten million different compounds, a large majority of all chemical compounds. Carbon also has the highest sublimation point of all elements, although thermodynamically prone to oxidation, carbon resists oxidation more effectively than elements such as iron and copper that are weaker reducing agents at room temperature. Carbon is the element, with a ground-state electron configuration of 1s22s22p2. Its first four ionisation energies,1086.5,2352.6,4620.5 and 6222.7 kJ/mol, are higher than those of the heavier group 14 elements. Carbons covalent radii are normally taken as 77.2 pm,66.7 pm and 60.3 pm, although these may vary depending on coordination number, in general, covalent radius decreases with lower coordination number and higher bond order. Carbon compounds form the basis of all life on Earth
9.
Triple bond
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A triple bond in chemistry is a chemical bond between two atoms involving six bonding electrons instead of the usual two in a covalent single bond. The most common triple bond, that between two atoms, can be found in alkynes. Other functional groups containing a triple bond are cyanides and isocyanides, some diatomic molecules, such as dinitrogen and carbon monoxide are also triple bonded. In skeletal formula the triple bond is drawn as three parallel lines between the two connected atoms, triple bonds are stronger and shorter than the equivalent single bonds or double bonds, with a bond order of three. The types of bonding can be explained through in terms of orbital hybridization, in the case of acetylene each carbon atom has two sp orbitals and two p-orbitals. The two sp orbitals are linear with 180° angles and occupy the x-axis, the p-orbitals are perpendicular on the y-axis and the z-axis. When the carbon atoms approach each other the sp orbitals overlap to form a sigma bond. At the same time the approach and together they form a pz-pz pi-bond. Likewise, the pair of py-orbitals form a py-py pi-bond. The result is formation of one bond and two pi bonds. In the bent bond model the triple bond can also formed by the overlapping of three sp3 lobes without the need to invoke a pi-bond
10.
Nitrogen
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Nitrogen is a chemical element with symbol N and atomic number 7. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772, although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is generally accorded the credit because his work was published first. Nitrogen is the lightest member of group 15 of the periodic table, the name comes from the Greek πνίγειν to choke, directly referencing nitrogens asphyxiating properties. It is an element in the universe, estimated at about seventh in total abundance in the Milky Way. At standard temperature and pressure, two atoms of the element bind to form dinitrogen, a colourless and odorless diatomic gas with the formula N2, dinitrogen forms about 78% of Earths atmosphere, making it the most abundant uncombined element. Nitrogen occurs in all organisms, primarily in amino acids, in the nucleic acids, the human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes movement of the element from the air, into the biosphere and organic compounds, many industrially important compounds, such as ammonia, nitric acid, organic nitrates, and cyanides, contain nitrogen. The extremely strong bond in elemental nitrogen, the second strongest bond in any diatomic molecule. Synthetically produced ammonia and nitrates are key industrial fertilisers, and fertiliser nitrates are key pollutants in the eutrophication of water systems. Apart from its use in fertilisers and energy-stores, nitrogen is a constituent of organic compounds as diverse as Kevlar used in high-strength fabric, Nitrogen is a constituent of every major pharmacological drug class, including antibiotics. Many notable nitrogen-containing drugs, such as the caffeine and morphine or the synthetic amphetamines. Nitrogen compounds have a long history, ammonium chloride having been known to Herodotus. They were well known by the Middle Ages, alchemists knew nitric acid as aqua fortis, as well as other nitrogen compounds such as ammonium salts and nitrate salts. The mixture of nitric and hydrochloric acids was known as aqua regia, celebrated for its ability to dissolve gold, the discovery of nitrogen is attributed to the Scottish physician Daniel Rutherford in 1772, who called it noxious air. Though he did not recognise it as a different chemical substance, he clearly distinguished it from Joseph Blacks fixed air. The fact that there was a component of air that does not support combustion was clear to Rutherford, Nitrogen was also studied at about the same time by Carl Wilhelm Scheele, Henry Cavendish, and Joseph Priestley, who referred to it as burnt air or phlogisticated air. Nitrogen gas was inert enough that Antoine Lavoisier referred to it as air or azote, from the Greek word άζωτικός. In an atmosphere of nitrogen, animals died and flames were extinguished
11.
Salt (chemistry)
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In chemistry, a salt is an ionic compound that results from the neutralization reaction of an acid and a base. Salts are composed of related numbers of cations and anions so that the product is electrically neutral and these component ions can be inorganic, such as chloride, or organic, such as acetate, and can be monatomic, such as fluoride, or polyatomic, such as sulfate. There are several varieties of salts, salts that hydrolyze to produce hydroxide ions when dissolved in water are alkali salts, whilst those that hydrolyze to produce hydronium ions in water are acidic salts. Neutral salts are those salts that are neither acidic nor basic, zwitterions contain an anionic centre and a cationic centre in the same molecule, but are not considered to be salts. Examples of zwitterions include amino acids, many metabolites, peptides, usually, non-dissolved salts at standard conditions for temperature and pressure are solid, but there are exceptions. Molten salts and solutions containing dissolved salts are called electrolytes, as they are able to conduct electricity. As observed in the cytoplasm of cells, in blood, urine, plant saps and mineral waters, therefore, their salt content is given for the respective ions. Salts can appear to be clear and transparent, opaque, and even metallic, in many cases, the apparent opacity or transparency are only related to the difference in size of the individual monocrystals. Since light reflects from the boundaries, larger crystals tend to be transparent. The color of the salt is due to the electronic structure in the d-orbitals of transition elements or in the conjugated organic dye framework. Different salts can elicit all five basic tastes, e. g. salty, sweet, sour, bitter, and umami or savory. Salts of strong acids and strong bases are non-volatile and odorless and that slow, partial decomposition is usually accelerated by the presence of water, since hydrolysis is the other half of the reversible reaction equation of formation of weak salts. Many ionic compounds can be dissolved in water or other similar solvents, the exact combination of ions involved makes each compound have a unique solubility in any solvent. The solubility is dependent on how well each ion interacts with the solvent, for example, all salts of sodium, potassium and ammonium are soluble in water, as are all nitrates and many sulfates – barium sulfate, calcium sulfate and lead sulfate are examples of exceptions. However, ions that bind tightly to each other and form highly stable lattices are less soluble, for example, most carbonate salts are not soluble in water, such as lead carbonate and barium carbonate. Some soluble carbonate salts are, sodium carbonate, potassium carbonate, solid salts do not conduct electricity. Moreover, solutions of salts also conduct electricity, the name of a salt starts with the name of the cation followed by the name of the anion. Salts are often referred to only by the name of the cation or by the name of the anion. g
12.
Sodium cyanide
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Sodium cyanide is an inorganic compound with the formula NaCN. It is a white, water-soluble solid, cyanide has a high affinity for metals, which leads to the high toxicity of this salt. Its main application, in mining, also exploits its high reactivity toward metals. Formerly it was prepared by the Castner-Kellner process involving the reaction of sodium amide with carbon at elevated temperatures, naNH2 + C → NaCN + H2 The structure of solid NaCN is related to that of sodium chloride. The anions and cations are each six-coordinate, potassium cyanide adopts a similar structure. Each Na+ forms pi-bonds to two CN− groups as well as two bent Na---CN and two bent Na---NC links. Because the salt is derived from an acid, sodium cyanide readily reverts to HCN by hydrolysis, the moist solid emits small amounts of hydrogen cyanide. Sodium cyanide reacts rapidly with acids to release hydrogen cyanide. This dangerous process represents a significant risk associated with cyanide salts, few other methods exist for this extraction process. Several commercially significant chemical compounds are derived from cyanide, including cyanuric chloride, cyanogen chloride, in organic synthesis, cyanide, which is classified as a strong nucleophile, is used to prepare nitriles, which occur widely in many specialty chemicals, including pharmaceuticals. Being highly toxic, sodium cyanide is used to kill or stun rapidly such as in widely illegal cyanide fishing, sodium cyanide, like other soluble cyanide salts, is among the most rapidly acting of all known poisons. NaCN is a potent inhibitor of respiration, acting on mitochondrial cytochrome oxidase and this results in decreased oxidative metabolism and oxygen utilization. Lactic acidosis then occurs as a consequence of anaerobic metabolism, an oral dosage as small as 200–300 mg can be fatal. Cyanide Institut national de recherche et de sécurité, Cyanure de sodium, Cyanure de potassium, Fiche toxicologique n°111, Paris,2006,6 pp
13.
Potassium cyanide
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Potassium cyanide is a compound with the formula KCN. This colorless crystalline salt, similar in appearance to sugar, is soluble in water. Most KCN is used in mining, organic synthesis. Smaller applications include jewelry for chemical gilding and buffing, the moist solid emits small amounts of hydrogen cyanide due to hydrolysis, which smells like bitter almonds. Not everyone, however, can smell this, the ability to do so is a genetic trait, the taste of potassium cyanide has been described as acrid with a burning sensation. Prior to 1900 AD, before the invention of the Castner process, despite the cyanide ions being diatomic, and thus less symmetric than chloride, they rotate so rapidly, their time-averaged shape is spherical. At low temperature and high pressure, this rotation is hindered. KCN and sodium cyanide are widely used in synthesis for the preparation of nitriles and carboxylic acids. KCN is used as a fixer in the wet plate collodion process. The KCN dissolves silver where it has not been made insoluble by the developer and this reveals and stabilizes the image, making it no longer sensitive to light. Modern wet plate photographers may prefer less toxic fixers, often opting for the less toxic Sodium thiosulphate, potassium cyanide is a potent inhibitor of cellular respiration, acting on mitochondrial cytochrome c oxidase, hence blocking oxidative phosphorylation. This prevents the body from oxidizing food to produce useful energy, lactic acidosis then occurs as a consequence of anaerobic metabolism. Initially, acute cyanide poisoning causes a red or ruddy complexion in the victim because the tissues are not able to use the oxygen in the blood, during this period the victim may suffer convulsions. Death is caused by cerebral hypoxia, the lethal dose for potassium cyanide is 200–300 mg. Its toxicity when ingested depends on the acidity of the stomach, because it must react with an acid to hydrogen cyanide. Grigori Rasputin may have survived a potassium cyanide poisoning because his stomach acidity was unusually low, danish writer Gustav Wied and members of the LTTE involved in the assassination of Indian prime minister Rajiv Gandhi. Jason Altom, who was a graduate student in the lab of Nobel-Prizewinning chemist EJ Corey at Harvard. KCN can be detoxified most efficiently with hydrogen peroxide or with a solution of sodium hypochlorite, fiche toxicologique n°111, Paris, INRS, 6pp
14.
Nitrile
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A nitrile is any organic compound that has a −C≡N functional group. The prefix cyano- is used interchangeably with the nitrile in industrial literature. Nitriles are found in many compounds, including methyl cyanoacrylate, used in super glue, and nitrile rubber. Nitrile rubber is widely used as automotive and other seals since it is resistant to fuels and oils. Organic compounds containing multiple nitrile groups are known as cyanocarbons, inorganic compounds containing the −C≡N group are not called nitriles, but cyanides instead. Though both nitriles and cyanides can be derived from cyanide salts, most nitriles are not nearly as toxic, the N−C−C geometry is linear in nitriles, reflecting the sp hybridization of the triply bonded carbon. The C−N distance is short at 1.16 Å, consistent with a triple bond, Nitriles are polar, as indicated by high dipole moments. As liquids, they have high dielectric constants, often in the 30s, the first compound of the homolog row of nitriles, the nitrile of formic acid, hydrogen cyanide was first synthesized by C. W. Scheele in 1782. In 1811 J. L. Gay-Lussac was able to prepare the very toxic, théophile-Jules Pelouze synthesized propionitrile in 1834 suggesting it to be an ether of propionic alcohol and hydrocyanic acid. The synthesis of benzonitrile by Hermann Fehling in 1844, by heating ammonium benzoate, was the first method yielding enough of the substance for chemical research and he determined the structure by comparing it to the already known synthesis of hydrogen cyanide by heating ammonium formate to his results. He coined the name nitrile for the substance, which became the name for this group of compounds. Industrially, the methods for producing nitriles are ammoxidation and hydrocyanation. Both routes are green in the sense that they do not generate stoichiometric amounts of salts, in ammoxidation, a hydrocarbon is partially oxidized in the presence of ammonia. This conversion is practiced on a scale for acrylonitrile, CH3CH=CH2 + 3⁄2 O2 + NH3 → NCCH=CH2 +3 H2O In the production of acrylonitrile. On an industrial scale, several derivatives of benzonitrile, phthalonitrile, the process is catalysed by metal oxides and is assumed to proceed via the imine. Hydrocyanation is a method for producing nitriles from hydrogen cyanide. In the Kolbe nitrile synthesis, alkyl halides undergo nucleophilic aliphatic substitution with alkali metal cyanides, aryl nitriles are prepared in the Rosenmund-von Braun synthesis. The cyanohydrins are a class of nitriles
15.
Covalent bond
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A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, for many molecules, the sharing of electrons allows each atom to attain the equivalent of a full outer shell, corresponding to a stable electronic configuration. Covalent bonding includes many kinds of interactions, including σ-bonding, π-bonding, metal-to-metal bonding, agostic interactions, bent bonds, the term covalent bond dates from 1939. In the molecule H2, the atoms share the two electrons via covalent bonding. Covalency is greatest between atoms of similar electronegativities, thus, covalent bonding does not necessarily require that the two atoms be of the same elements, only that they be of comparable electronegativity. Covalent bonding that entails sharing of electrons more than two atoms is said to be delocalized. The term covalence in regard to bonding was first used in 1919 by Irving Langmuir in a Journal of the American Chemical Society article entitled The Arrangement of Electrons in Atoms and Molecules. Langmuir wrote that we shall denote by the term covalence the number of pairs of electrons that an atom shares with its neighbors. The idea of covalent bonding can be traced several years before 1919 to Gilbert N. Lewis and he introduced the Lewis notation or electron dot notation or Lewis dot structure, in which valence electrons are represented as dots around the atomic symbols. Pairs of electrons located between atoms represent covalent bonds, multiple pairs represent multiple bonds, such as double bonds and triple bonds. An alternative form of representation, not shown here, has bond-forming electron pairs represented as solid lines, Lewis proposed that an atom forms enough covalent bonds to form a full outer electron shell. In the diagram of methane shown here, the atom has a valence of four and is, therefore, surrounded by eight electrons, four from the carbon itself. Each hydrogen has a valence of one and is surrounded by two electrons – its own one electron plus one from the carbon, walter Heitler and Fritz London are credited with the first successful quantum mechanical explanation of a chemical bond in 1927. Their work was based on the valence bond model, which assumes that a bond is formed when there is good overlap between the atomic orbitals of participating atoms. Atomic orbitals have specific directional properties leading to different types of covalent bonds, sigma bonds are the strongest covalent bonds and are due to head-on overlapping of orbitals on two different atoms. A single bond is usually a σ bond, pi bonds are weaker and are due to lateral overlap between p orbitals. A double bond between two given atoms consists of one σ and one π bond, and a bond is one σ. Covalent bonds are also affected by the electronegativity of the atoms which determines the chemical polarity of the bond
16.
Methyl group
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A methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms — CH3. In formulas, the group is often abbreviated Me, such hydrocarbon groups occur in many organic compounds. It is a stable group in most molecules. While the methyl group is part of a larger molecule. The anion has eight electrons, the radical seven and the cation six. All three forms are highly reactive and rarely observed, the methylium cation exists in the gas phase, but is otherwise not encountered. Some compounds are considered to be sources of the CH3+ cation, the methanide anion exists only in rarefied gas phase or under exotic conditions. It can be produced by electrical discharge in ketene at low pressure, such reagents are generally prepared from the methyl halides, M + CH3X → MCH3 where M is an alkali metal. The methyl radical has the formula CH3 and it exists in dilute gases, but in more concentrated form it readily dimerizes to ethane. It can be produced by decomposition of only certain compounds. The reactivity of a methyl group depends on the adjacent substituents, methyl groups can be quite unreactive. For example, in compounds, the methyl group resists attack by even the strongest acids. The oxidation of a group occurs widely in nature and industry. The oxidation products derived from methyl are CH2OH, CHO, for example, permanganate often converts a methyl group to a carboxyl group, e. g. the conversion of toluene to benzoic acid. Ultimately oxidation of methyl groups gives protons and carbon dioxide, as seen in combustion, demethylation is a common process, and reagents that undergo this reaction are called methylating agents. Common methylating agents are dimethyl sulfate, methyl iodide, and methyl triflate, methanogenesis, the source of natural gas, arises via a demethylation reaction. Certain methyl groups can be deprotonated, for example, the acidity of the methyl groups in acetone is about 1020 more acidic than methane. The resulting carbanions are key intermediates in many reactions in organic synthesis and biosynthesis, fatty acids are produced in this way
17.
Cyanohydrin
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A cyanohydrin is a functional group found in organic compounds in which a cyano and a hydroxy group are attached to the same carbon atom. The general formula is R2CCN, where R is H, alkyl, Cyanohydrins are industrially important precursors to carboxylic acids and some amino acids. Cyanohydrins are also prepared by displacement of sulfite by cyanide salts, acetone cyanohydrin, 2CCN is the cyanohydrin of acetone. It is generated as an intermediate in the production of methyl methacrylate. In the laboratory, this serves as a source of HCN. Thus, acetone cyanohydrin can be used for the preparation of other cyanohydrins, for the transformation of HCN to Michael acceptors, and for the formylation of arenes. Treatment of this cyanohydrin with lithium hydride affords anhydrous lithium cyanide, Mandelonitrile, with the formula C6H5CHCN, related cyanogenic glycosides are known, such as amygdalin. Glycolonitrile, also called hydroxyacetonitrile or formaldehyde cyanohydrin, is the compound with the formula HOCH2CN. It is the simplest cyanohydrin, being derived from formaldehyde, halohydrin IUPACs Gold Book definition of cyanohydrins
18.
Space-filling model
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Atoms of different chemical elements are usually represented by spheres of different colors. They are distinguished from other 3D representations, such as the ball-and-stick and skeletal models and they are useful for visualizing the effective shape and relative dimensions of the molecule, and the shapes of surface a given static conformer might present. For this reason, such models are of greater utility if they can be used dynamically, especially used with complex molecules. Space-filling models arise out of a desire to represent molecules in ways that reflect the electronic surfaces that molecules present, in short, for reasons of utility, crystallographic data historically have appeared in presentations closer to ball-and-stick models. In 1952, Robert Corey and Linus Pauling described accurate scale models of molecules which they had built at Caltech, a connector was designed—a metal bushing that threaded into each sphere at the center of each flat face. The two spheres were then held together by a metal rod inserted into the pair of opposing bushing. The models also had special features to allow representation of hydrogen bonds, such colour-coded, bond length-defined, van der Waals-type space-filling models are now commonly known as CPK models, after these three developers of the specific concept. The two closing images give examples of the type of calculation and representation, and its utility. Van der Waals surface CPK coloring Molecular graphics Software for molecular modeling Molecular design software More on molecular models and a couple of examples from chemistry and biology
19.
Electrostatic potential
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An electric potential is the amount of work needed to move a unit positive charge from a reference point to a specific point inside the field without producing any acceleration. Typically, the point is Earth or a point at Infinity. By dividing out the charge on the particle a remainder is obtained that is a property of the field itself. This value can be calculated in either a static or an electric field at a specific time in units of joules per coulomb. The electric potential at infinity is assumed to be zero, a generalized electric scalar potential is also used in electrodynamics when time-varying electromagnetic fields are present, but this can not be so simply calculated. The electric potential and the vector potential together form a four vector. Classical mechanics explores concepts such as force, energy, potential etc, force and potential energy are directly related. A net force acting on any object will cause it to accelerate, as it rolls downhill its potential energy decreases, being translated to motion, inertial energy. It is possible to define the potential of certain force fields so that the energy of an object in that field depends only on the position of the object with respect to the field. Two such force fields are the field and an electric field. Such fields must affect objects due to the properties of the object. Objects may possess a property known as charge and an electric field exerts a force on charged objects. If the charged object has a charge the force will be in the direction of the electric field vector at that point while if the charge is negative the force will be in the opposite direction. The magnitude of the force is given by the quantity of the charge multiplied by the magnitude of the field vector. The electric potential at a point r in an electric field E is given by the line integral where C is an arbitrary path connecting the point with zero potential to r. When the curl ∇ × E is zero, the integral above does not depend on the specific path C chosen. The concept of electric potential is linked with potential energy. A test charge q has a potential energy UE given by U E = q V
20.
Isocyanide
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An isocyanide is an organic compound with the functional group -N≡C. It is the isomer of the cyanide, hence the prefix iso. The organic fragment is connected to the group via the nitrogen atom. They are used as building blocks for the synthesis of other compounds, the C-N distance in isocyanides is very short,1.158 Å in methyl isocyanide. The C-N-C angles are near 180°, akin to carbon monoxide, isocyanides are described by two resonance structures, one with a triple bond between the nitrogen and the carbon and one with a double bond between. Surprisingly, the one, with a carbenic character is the more important. Nevertheless, the π lone pair of the nitrogen, responsible of the zwitterionic structure, isocyanides are best shown as a mixture of both resonance structures. 5 Hz for the isocyanide 13C nucleus and 5–14 Hz for the 13C nucleus which the group is attached to. To quote from Lieke, Es besitzt einen penetranten, höchst unangenehmen Geruch, das Oeffnen eines Gefässes mit Cyanallyl reicht hin, note that in Liekes day, the difference between isocyanide and nitrile was not fully appreciated. Ivar Karl Ugi states that The development of the chemistry of isocyanides has probably suffered, through the characteristic odor of volatile isonitriles, which has been described by Hofmann and Gautier as highly specific, almost overpowering, horrible, and extremely distressing. It is true that many workers in this field have been turned away by the odour. Isocyanides have been investigated as potential non-lethal weapons, some isocyanides convey less offensive odours such as malt, natural rubber, creosote, mild cherry or old wood. Non-volatile derivatives such as tosylmethyl isocyanide do not have objectionable odors, while some isocyanides are toxic, others exhibit no appreciable toxicity for mammals. Referring to ethyl isocyanide, toxicological studies in the 1960s at Bayer showed that oral, the first isocyanide, allyl isocyanide, was reported in 1859 by the chemist Lieke from the reaction of allyl iodide and silver cyanide. Normally the alkylation of a metal cyanide gives a nitrile. Commonly, isocyanides are synthesized by dehydration of a formamide, the formamide can be dehydrated with phosphorus oxychloride, phosgene, diphosgene, or the Burgess Reagent. RNHCH + POCl3 → RNC + PO2Cl +2 HCl In the carbylamine reaction potassium hydroxide reacts with chloroform to produce dichlorocarbene and this then converts primary amines to isocyanides. As it is effective for primary amines it is used as a chemical test for their presence
21.
IUPAC nomenclature of organic chemistry
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It is published in the Nomenclature of Organic Chemistry. Ideally, every possible organic compound should have a name from which a structural formula can be created. There is also an IUPAC nomenclature of inorganic chemistry, otherwise the common or trivial name may be used, often derived from the source of the compound. In addition, very long names may be less concise than structural formulae, in chemistry, a number of prefixes, suffixes and infixes are used to describe the type and position of functional groups in the compound. The steps for naming an organic compound are, Identification of the parent hydrocarbon chain and this chain must obey the following rules, in order of precedence, It should have the maximum number of substituents of the suffix functional group. By suffix, it is meant that the parent functional group should have a suffix, if more than one functional group is present, the one with highest precedence should be used. It should have the number of multiple bonds It should have the maximum number of single bonds. It should have the maximum length, Identification of the parent functional group, if any, with the highest order of precedence. Side chains are the chains that are not in the parent chain. Identification of the functional groups, if any, and naming them by their ionic prefixes. Different side-chains and functional groups will be grouped together in alphabetical order, when both side chains and secondary functional groups are present, they should be written mixed together in one group rather than in two separate groups. Locants are the numbers on the carbons to which the substituent is directly attached, has the lowest-numbered locants for multiple bonds. Has the lowest-numbered locants for prefixes, numbering of the various substituents and bonds with their locants. If there are two side-chains with the alpha carbon, the number will be written twice. If there are double bonds and triple bonds, en is written before yne. When the main group is a terminal functional group, there is no need to number it. Wherever it says with numbers, it is understood that between the word and the numbers, the prefix is used. Adding of punctuation, Commas are put between numbers Hyphens are put between a number and a letter Successive words are merged into one word Note, IUPAC uses one-word names throughout and this is why all parts are connected
22.
Organic compound
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An organic compound is virtually any chemical compound that contains carbon, although a consensus definition remains elusive and likely arbitrary. Organic compounds are rare terrestrially, but of importance because all known life is based on organic compounds. The most basic petrochemicals are considered the building blocks of organic chemistry, for historical reasons discussed below, a few types of carbon-containing compounds, such as carbides, carbonates, simple oxides of carbon, and cyanides are considered inorganic. The distinction between organic and inorganic compounds, while useful in organizing the vast subject of chemistry. Organic chemistry is the science concerned with all aspects of organic compounds, Organic synthesis is the methodology of their preparation. The word organic is historical, dating to the 1st century, for many centuries, Western alchemists believed in vitalism. This is the theory that certain compounds could be synthesized only from their classical elements—earth, water, air, vitalism taught that these organic compounds were fundamentally different from the inorganic compounds that could be obtained from the elements by chemical manipulation. Vitalism survived for a while even after the rise of modern atomic theory and it first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid, a compound known to occur only in living organisms, from cyanogen. A more decisive experiment was Wöhlers 1828 synthesis of urea from the inorganic salts potassium cyanate, urea had long been considered an organic compound, as it was known to occur only in the urine of living organisms. Wöhlers experiments were followed by others, in which increasingly complex organic substances were produced from inorganic ones without the involvement of any living organism. Even though vitalism has been discredited, scientific nomenclature retains the distinction between organic and inorganic compounds, still, even the broadest definition requires excluding alloys that contain carbon, including steel. The C-H definition excludes compounds that are considered organic, neither urea nor oxalic acid is organic by this definition, yet they were two key compounds in the vitalism debate. The IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid, other compounds lacking C-H bonds but traditionally considered organic include benzenehexol, mesoxalic acid, and carbon tetrachloride. Mellitic acid, which contains no C-H bonds, is considered an organic substance in Martian soil. The C-H bond-only rule also leads to somewhat arbitrary divisions in sets of carbon-fluorine compounds, for example, CF4 would be considered by this rule to be inorganic, whereas CF3H would be organic. Organic compounds may be classified in a variety of ways, one major distinction is between natural and synthetic compounds. Another distinction, based on the size of organic compounds, distinguishes between small molecules and polymers, natural compounds refer to those that are produced by plants or animals. Many of these are extracted from natural sources because they would be more expensive to produce artificially
23.
Functional group
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In organic chemistry, functional groups are specific groups of atoms or bonds within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of, however, its relative reactivity can be modified by other functional groups nearby. The atoms of functional groups are linked to other and to the rest of the molecule by covalent bonds. Any subgroup of atoms of a compound also may be called a radical, and if a covalent bond is broken homolytically, Functional groups can also be charged, e. g. in carboxylate salts, which turns the molecule into a polyatomic ion or a complex ion. Complexation and solvation is also caused by interactions of functional groups. In the common rule of thumb like dissolves like, it is the shared or mutually well-interacting functional groups give rise to solubility. For example, sugar dissolves in water because both share the functional group and hydroxyls interact strongly with each other. Combining the names of groups with the names of the parent alkanes generates what is termed a systematic nomenclature for naming organic compounds. In traditional nomenclature, the first carbon atom after the carbon that attaches to the group is called the alpha carbon, the second, beta carbon. IUPAC conventions call for numeric labeling of the position, e. g. 4-aminobutanoic acid, in traditional names various qualifiers are used to label isomers, for example isopropanol is an isomer is n-propanol. The following is a list of functional groups. In the formulas, the symbols R and R usually denote an attached hydrogen, or a side chain of any length. Functional groups, called hydrocarbyl, that only carbon and hydrogen. Each one differs in type of reactivity, there are also a large number of branched or ring alkanes that have specific names, e. g. tert-butyl, bornyl, cyclohexyl, etc. Hydrocarbons may form charged structures, positively charged carbocations or negative carbanions, examples are tropylium and triphenylmethyl cations and the cyclopentadienyl anion. Haloalkanes are a class of molecule that is defined by a carbon–halogen bond and this bond can be relatively weak or quite stable. In general, with the exception of fluorinated compounds, haloalkanes readily undergo nucleophilic substitution reactions or elimination reactions, the substitution on the carbon, the acidity of an adjacent proton, the solvent conditions, etc. all can influence the outcome of the reactivity. Compounds that contain nitrogen in this category may contain C-O bonds, compounds that contain sulfur exhibit unique chemistry due to their ability to form more bonds than oxygen, their lighter analogue on the periodic table
24.
Prussian blue
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Prussian blue is a dark blue pigment with the idealized chemical formula Fe 718. To better understand the situation in this complex compound the formula can also be written as Fe 43 · xH 2O. Another name for the color is Berlin blue or, in painting, Turnbulls blue is the same substance, but is made from different reagents, and its slightly different color stems from different impurities. Prussian blue was the first modern synthetic pigment and it is employed as a very fine colloidal dispersion, as the compound itself is not soluble in water. It is famously complex, owing to the presence of variable amounts of other ions, the pigment is used in paints, and it is the traditional blue in blueprints. In medicine, Prussian blue is used as an antidote for certain kinds of metal poisoning, e. g. by thallium. In particular it was used to absorb 137Cs+ from those poisoned in the Goiânia accident, the therapy exploits Prussian blues ion exchange properties and high affinity for certain soft metal cations. It is on the World Health Organizations List of Essential Medicines, Prussian blue lent its name to prussic acid, which was derived from it. In Germany, hydrogen cyanide is called Blausäure, and Joseph Louis Gay-Lussac gave cyanide its name, from the Greek word κυανός, because it is easily made, cheap, nontoxic, and intensely colored, Prussian blue has attracted many applications. It was adopted as a pigment very soon after its invention and was almost immediately used in oil, watercolor. The dominant uses are for pigments, about 12,000 tonnes of Prussian blue are produced annually for use in black, a variety of other pigments also contain the material. Engineers blue and the pigment formed on cyanotypes—giving them their common name blueprints, certain crayons were once colored with Prussian blue. It is also a popular pigment in paints, similarly, Prussian blue is the basis for laundry bluing. Prussian blues ability to incorporate monocations makes it useful as a agent for certain heavy metal poisons. Pharmaceutical-grade Prussian blue in particular is used for people who have ingested thallium or radioactive caesium, according to the International Atomic Energy Agency, an adult male can eat at least 10 g of Prussian blue per day without serious harm. The U. S. Prussian blue is a common stain used by pathologists to detect the presence of iron in biopsy specimens. The original stain formula, known historically as Perls Prussian blue after its inventor, German pathologist Max Perls, used separate solutions of potassium ferrocyanide, iron deposits in tissue then form the purple Prussian blue dye in place, and are visualized as blue or purple deposits. The formula is known as Perls Prussian blue and as Perls Prussian blue
25.
Isoelectronicity
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The species concerned are termed isoelectronic. This definition is sometimes termed valence isoelectronicity, in contrast with various alternatives, at one extreme these require identity of the total electron count and with it the entire electron configuration. More usually, alternatives are broader, and may extend to allowing different numbers of atoms in the species being compared, the importance of the concept lies in identifying significantly related species, as pairs or series. Isoelectronic species can be expected to show consistency and predictability in their properties. Electron-density calculations have been performed on many common substances, resulting in reaction predictions, identifying a new, rare or odd compound as isoelectronic with one already characterised offers clues to possible properties and reactions. The N atom and the O+ radical ion are isoelectronic because each has five electrons in the electronic shell. Similarly, the cations K+, Ca2+, and Sc3+ and the anions Cl−, S2−, in such monatomic cases, there is a clear trend in the sizes of such species, with atomic radius decreasing as charge increases. CO, CN−, N2 and NO+ are isoelectronic because each has two nuclei and 10 valence electrons, with each considered to have 5 of them. CO2, FCN, N2O, NO2+, N3−, and NCO− are all isoelectronic, isoelectronicity leads to the concept of hydrogen-like atoms, ions with one electron which are thus isoelectronic with hydrogen. The uncharged H 2C=C=O molecule and the zwitterionic H 2C=N+=N− molecule are isoelectronic, CH 3COCH3 and CH 3N 2CH3 are not isoelectronic. The amino acids tellurocysteine, selenocysteine, cysteine and serine are also considered isoelectronic
26.
Cassava
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Manihot esculenta is a woody shrub native to South America of the spurge family, Euphorbiaceae. It is extensively cultivated as a crop in tropical and subtropical regions for its edible starchy tuberous root. Though it is often called yuca in Spanish and in the United States, it differs from the yucca, Cassava, when dried to a powdery extract, is called tapioca, its fermented, flaky version is named garri. Cassava is the third-largest source of carbohydrates in the tropics, after rice. Cassava is a staple food in the developing world, providing a basic diet for over half a billion people. It is one of the most drought-tolerant crops, capable of growing on marginal soils, Nigeria is the worlds largest producer of cassava, while Thailand is the largest exporter of dried cassava. Cassava is classified as sweet or bitter. Like other roots and tubers, both bitter and sweet varieties of cassava contain antinutritional factors and toxins, with the bitter varieties containing much larger amounts, the more toxic varieties of cassava are a fall-back resource in times of famine or food insecurity in some places. Farmers often prefer the bitter varieties because they deter pests, animals, the cassava root is long and tapered, with a firm, homogeneous flesh encased in a detachable rind, about 1 mm thick, rough and brown on the outside. Commercial cultivars can be 5 to 10 cm in diameter at the top, a woody vascular bundle runs along the roots axis. The flesh can be chalk-white or yellowish, Cassava roots are very rich in starch and contain small amounts of calcium, phosphorus, and vitamin C. However, they are poor in protein and other nutrients, in contrast, cassava leaves are a good source of protein, but deficient in the amino acid methionine and possibly tryptophan. Forms of the domesticated species can also be found growing in the wild in the south of Brazil. By 4,600 BC, manioc pollen appears in the Gulf of Mexico lowlands, the oldest direct evidence of cassava cultivation comes from a 1, 400-year-old Maya site, Joya de Cerén, in El Salvador. With its high potential, it had become a staple food of the native populations of northern South America, southern Mesoamerica. Cassava was a food of pre-Columbian peoples in the Americas and is often portrayed in indigenous art. The Moche people often depicted yuca in their ceramics, spaniards in their early occupation of Caribbean islands did not want to eat cassava or maize, which they considered insubstantial, dangerous, and not nutritious. They much preferred foods from Spain, specifically wheat bread, olive oil, red wine, and meat, for these Christians in the New World, cassava was not suitable for communion since it could not undergo transubstantiation and become the body of Christ
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Nigeria
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Its coast in the south lies on the Gulf of Guinea in the Atlantic Ocean. It comprises 36 states and the Federal Capital Territory, where the capital, Nigeria is officially a democratic secular country. Modern-day Nigeria has been the site of numerous kingdoms and tribal states over the millennia, the modern state originated from British colonial rule beginning in the 19th century, and the merging of the Southern Nigeria Protectorate and Northern Nigeria Protectorate in 1914. The British set up administrative and legal structures whilst practising indirect rule through traditional chiefdoms, Nigeria became a formally independent federation in 1960, and plunged into a civil war from 1967 to 1970. Nigeria is often referred to as the Giant of Africa, owing to its large population, with approximately 184 million inhabitants, Nigeria is the most populous country in Africa and the seventh most populous country in the world. Nigeria has one of the largest populations of youth in the world, Nigeria is divided roughly in half between Christians, who live mostly in the southern part of the country, and Muslims in the northern part. A minority of the population practise religions indigenous to Nigeria, such as native to the Igbo. As of 2015, Nigeria is the worlds 20th largest economy, worth more than $500 billion and $1 trillion in terms of nominal GDP and it overtook South Africa to become Africas largest economy in 2014. The 2013 debt-to-GDP ratio was 11 percent, Nigeria is a member of the MINT group of countries, which are widely seen as the globes next BRIC-like economies. It is also listed among the Next Eleven economies set to become among the biggest in the world, Nigeria is a founding member of the African Union and a member of many other international organizations, including the United Nations, the Commonwealth of Nations and OPEC. The name Nigeria was taken from the Niger River running through the country and this name was coined in the late 19th century by British journalist Flora Shaw, who later married Lord Lugard, a British colonial administrator. The origin of the name Niger, which applied only to the middle reaches of the Niger River, is uncertain. The word is likely an alteration of the Tuareg name egerew n-igerewen used by inhabitants along the middle reaches of the river around Timbuktu prior to 19th-century European colonialism. The Nok civilisation of Northern Nigeria flourished between 500 BC and AD200, producing life-sized terracotta figures which are some of the earliest known sculptures in Sub-Saharan Africa, further north, the cities Kano and Katsina have a recorded history dating to around 999 AD. Hausa kingdoms and the Kanem-Bornu Empire prospered as trade posts between North and West Africa, the Kingdom of Nri of the Igbo people consolidated in the 10th century and continued until it lost its sovereignty to the British in 1911. Nri was ruled by the Eze Nri, and the city of Nri is considered to be the foundation of Igbo culture, Nri and Aguleri, where the Igbo creation myth originates, are in the territory of the Umeuri clan. Members of the clan trace their lineages back to the patriarchal king-figure Eri, in West Africa, the oldest bronzes made using the lost-wax process were from Igbo Ukwu, a city under Nri influence. The Yoruba kingdoms of Ife and Oyo in southwestern Nigeria became prominent in the 12th and 14th centuries, the oldest signs of human settlement at Ifes current site date back to the 9th century, and its material culture includes terracotta and bronze figures
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Bacterium
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Bacteria constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods, Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, and only half of the bacterial phyla have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology, There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. There are approximately 5×1030 bacteria on Earth, forming a biomass which exceeds that of all plants, Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of bodies and bacteria are responsible for the putrefaction stage in this process. In March 2013, data reported by researchers in October 2012, was published and it was suggested that bacteria thrive in the Mariana Trench, which with a depth of up to 11 kilometres is the deepest known part of the oceans. Other researchers reported related studies that microbes thrive inside rocks up to 580 metres below the sea floor under 2.6 kilometres of ocean off the coast of the northwestern United States. According to one of the researchers, You can find microbes everywhere—theyre extremely adaptable to conditions, the vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, though many are beneficial particularly in the gut flora. However several species of bacteria are pathogenic and cause diseases, including cholera, syphilis, anthrax, leprosy. The most common fatal diseases are respiratory infections, with tuberculosis alone killing about 2 million people per year. In developed countries, antibiotics are used to treat infections and are also used in farming, making antibiotic resistance a growing problem. Once regarded as constituting the class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and these evolutionary domains are called Bacteria and Archaea. The ancestors of modern bacteria were unicellular microorganisms that were the first forms of life to appear on Earth, for about 3 billion years, most organisms were microscopic, and bacteria and archaea were the dominant forms of life. In 2008, fossils of macroorganisms were discovered and named as the Francevillian biota, however, gene sequences can be used to reconstruct the bacterial phylogeny, and these studies indicate that bacteria diverged first from the archaeal/eukaryotic lineage. Bacteria were also involved in the second great evolutionary divergence, that of the archaea, here, eukaryotes resulted from the entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves possibly related to the Archaea
29.
Fungus
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A fungus is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from the other eukaryotic life kingdoms of plants, a characteristic that places fungi in a different kingdom from plants, bacteria and some protists, is chitin in their cell walls. Similar to animals, fungi are heterotrophs, they acquire their food by absorbing dissolved molecules, growth is their means of mobility, except for spores, which may travel through the air or water. Fungi are the principal decomposers in ecological systems and this fungal group is distinct from the structurally similar myxomycetes and oomycetes. The discipline of biology devoted to the study of fungi is known as mycology, in the past, mycology was regarded as a branch of botany, although it is now known fungi are genetically more closely related to animals than to plants. Abundant worldwide, most fungi are inconspicuous because of the size of their structures. Fungi include symbionts of plants, animals, or other fungi and they may become noticeable when fruiting, either as mushrooms or as molds. Fungi perform a role in the decomposition of organic matter and have fundamental roles in nutrient cycling. Since the 1940s, fungi have been used for the production of antibiotics, Fungi are also used as biological pesticides to control weeds, plant diseases and insect pests. Many species produce bioactive compounds called mycotoxins, such as alkaloids and polyketides, the fruiting structures of a few species contain psychotropic compounds and are consumed recreationally or in traditional spiritual ceremonies. Fungi can break down manufactured materials and buildings, and become significant pathogens of humans, losses of crops due to fungal diseases or food spoilage can have a large impact on human food supplies and local economies. The fungus kingdom encompasses a diversity of taxa with varied ecologies, life cycle strategies. However, little is known of the biodiversity of Kingdom Fungi. Advances in molecular genetics have opened the way for DNA analysis to be incorporated into taxonomy, phylogenetic studies published in the last decade have helped reshape the classification within Kingdom Fungi, which is divided into one subkingdom, seven phyla, and ten subphyla. The English word fungus is directly adopted from the Latin fungus, used in the writings of Horace, a group of all the fungi present in a particular area or geographic region is known as mycobiota, e. g. the mycobiota of Ireland. Like plants, fungi grow in soil and, in the case of mushrooms, form conspicuous fruit bodies. The fungi are now considered a kingdom, distinct from both plants and animals, from which they appear to have diverged around one billion years ago. Fungi have membrane-bound cytoplasmic organelles such as mitochondria, sterol-containing membranes and they have a characteristic range of soluble carbohydrates and storage compounds, including sugar alcohols, disaccharides, and polysaccharides
30.
Algae
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Algae is an informal term for a large, diverse group of photosynthetic organisms which are not necessarily closely related, and is thus polyphyletic. Included organisms range from unicellular genera, such as Chlorella and the diatoms, to forms, such as the giant kelp. Most are aquatic and autotrophic and lack many of the cell and tissue types, such as stomata, xylem, and phloem. No definition of algae is generally accepted, one definition is that algae have chlorophyll as their primary photosynthetic pigment and lack a sterile covering of cells around their reproductive cells. Some authors exclude all prokaryotes thus do not consider cyanobacteria as algae, Algae constitute a polyphyletic group since they do not include a common ancestor, and although their plastids seem to have a single origin, from cyanobacteria, they were acquired in different ways. Green algae are examples of algae that have primary chloroplasts derived from endosymbiotic cyanobacteria, diatoms and brown algae are examples of algae with secondary chloroplasts derived from an endosymbiotic red alga. Algae exhibit a range of reproductive strategies, from simple asexual cell division to complex forms of sexual reproduction. Algae lack the various structures that characterize land plants, such as the phyllids of bryophytes, rhizoids in nonvascular plants, and the roots, leaves, and other organs found in tracheophytes. Most are phototrophic, although some are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some other heterotrophic organisms, such as the apicomplexans, are derived from cells whose ancestors possessed plastids. Fossilized filamentous algae from the Vindhya basin have been dated back to 1.6 to 1.7 billion years ago, the singular alga is the Latin word for seaweed and retains that meaning in English. Although some speculate that it is related to Latin algēre, be cold, a more likely source is alliga, binding, entwining. The Ancient Greek word for seaweed was φῦκος, which could mean either the seaweed or a red dye derived from it, the Latinization, fūcus, meant primarily the cosmetic rouge. It could be any color, black, red, green, accordingly, the modern study of marine and freshwater algae is called either phycology or algology, depending on whether the Greek or Latin root is used. The name Fucus appears in a number of taxa, most algae contain chloroplasts that are similar in structure to cyanobacteria. Chloroplasts contain circular DNA like that in cyanobacteria and presumably represent reduced endosymbiotic cyanobacteria, however, the exact origin of the chloroplasts is different among separate lineages of algae, reflecting their acquisition during different endosymbiotic events. The table below describes the composition of the three groups of algae. Their lineage relationships are shown in the figure in the upper right, many of these groups contain some members that are no longer photosynthetic
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Almond
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The almond is a species of tree native to the Middle East, the Indian subcontinent and North Africa. Almond is also the name of the edible and widely cultivated seed of this tree, within the genus Prunus, it is classified with the peach in the subgenus Amygdalus, distinguished from the other subgenera by corrugations on the shell surrounding the seed. The fruit of the almond is a drupe, consisting of a hull and a hard shell with the seed. Shelling almonds refers to removing the shell to reveal the seed, almonds are sold shelled or unshelled. Blanched almonds are shelled almonds that have been treated with hot water to soften the seedcoat, the almond is a deciduous tree, growing 4–10 m in height, with a trunk of up to 30 cm in diameter. The young twigs are green at first, becoming purplish where exposed to sunlight, the leaves are 3–5 inches long, with a serrated margin and a 2.5 cm petiole. The flowers are white to pink, 3–5 cm diameter with five petals, produced singly or in pairs. Almond grows best in Mediterranean climates with warm, dry summers and mild, the optimal temperature for their growth is between 15 and 30 °C and the tree buds have a chilling requirement of 300 to 600 hours below 7.2 °C to break dormancy. Almonds begin bearing an economic crop in the year after planting. Trees reach full bearing five to six years after planting, the fruit matures in the autumn, 7–8 months after flowering. The almond fruit measures 3. 5–6 cm long, in botanical terms, it is not a nut but a drupe. The outer covering or exocarp, fleshy in other members of Prunus such as the plum and cherry, is instead a thick, leathery, grey-green coat, inside the hull is a reticulated, hard, woody shell called the endocarp. Inside the shell is the seed, commonly called a nut. Generally, one seed is present, but occasionally two occur, the almond is native to the Mediterranean climate region of the Middle East, eastward as far as the Yamuna River in India. The wild form of domesticated almond grows in parts of the Levant, the fruit of the wild forms contains the glycoside amygdalin, which becomes transformed into deadly prussic acid after crushing, chewing, or any other injury to the seed. Selection of the type from the many bitter types in the wild marked the beginning of almond domestication. It is unclear as to which wild ancestor of the created the domesticated species. Zohary and Hopf believe that almonds were one of the earliest domesticated fruit trees due to the ability of the grower to raise attractive almonds from seed
32.
Apricot
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An apricot is a fruit, or the tree that bears the fruit, of several species in the genus Prunus. The apricot is a tree, 8–12 m tall, with a trunk up to 40 cm in diameter. The leaves are ovate, 5–9 cm long and 4–8 cm wide, with a base, a pointed tip. The flowers are 2–4.5 cm in diameter, with five white to pinkish petals, the flesh is usually firm and not very juicy. Its taste can range from sweet to tart, the single seed is enclosed in a hard, stony shell, often called a stone, with a grainy, smooth texture except for three ridges running down one side. The origin of the apricot is disputed and it was known in Armenia during ancient times, and has been cultivated there for so long that it is often thought to have originated there. Its scientific name Prunus armeniaca derives from that assumption, for example, the Belgian arborist baron de Poerderlé, writing in the 1770s, asserted, Cet arbre tire son nom de lArménie, province dAsie, doù il est originaire et doù il fut porté en Europe. An archaeological excavation at Garni in Armenia found apricot seeds in an Eneolithic-era site, other sources say that the apricot was first cultivated in India in about 3000 BC. Subsequent sources were often confused about the origin of the species, john Claudius Loudon believed it had a wide native range including Armenia, the Caucasus, the Himalayas, China, and Japan. Apricots have been cultivated in Persia since antiquity, and dried ones were an important commodity on Persian trade routes, apricots remain an important fruit in modern-day Iran, where they are known under the common name of zard-ālū. Egyptians usually dry apricots, add sweetener, and then use them to make a drink called amar al-dīn, in the 17th century, English settlers brought the apricot to the English colonies in the New World. Most of modern American production of apricots comes from the seedlings carried to the west coast by Spanish missionaries, almost all U. S. commercial production is in California, with some in Washington and Utah. In states other than South Australia, apricots are still grown, particularly in Tasmania and western Victoria and southwest New South Wales, today, apricot cultivation has spread to all parts of the globe with climates that support it. Although the apricot is native to a climate region with cold winters. A dry climate is good for fruit maturation, the tree is slightly more cold-hardy than the peach, tolerating winter temperatures as cold as −30 °C or lower if healthy. A limiting factor in culture is spring frosts, They tend to flower very early. Furthermore, the trees are sensitive to changes during the winter season. In China, winters can be cold, but temperatures tend to be more stable than in Europe and especially North America
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Apple
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The apple tree is a deciduous tree in the rose family best known for its sweet, pomaceous fruit, the apple. It is cultivated worldwide as a tree, and is the most widely grown species in the genus Malus. The tree originated in Central Asia, where its wild ancestor, Apples have been grown for thousands of years in Asia and Europe, and were brought to North America by European colonists. Apples have religious and mythological significance in many cultures, including Norse, Greek, Apple trees are large if grown from seed. Generally apple cultivars are propagated by grafting onto rootstocks, which control the size of the resulting tree, There are more than 7,500 known cultivars of apples, resulting in a range of desired characteristics. Different cultivars are bred for various tastes and uses, including cooking, eating raw, trees and fruit are prone to a number of fungal, bacterial and pest problems, which can be controlled by a number of organic and non-organic means. In 2010, the genome was sequenced as part of research on disease control. Worldwide production of apples in 2014 was 84.6 million tonnes, the apple is a deciduous tree, generally standing 1.8 to 4.6 m tall in cultivation and up to 12 m in the wild. When cultivated, the size, shape and branch density are determined by rootstock selection, the leaves are alternately arranged dark green-colored simple ovals with serrated margins and slightly downy undersides. Blossoms are produced in spring simultaneously with the budding of the leaves, the 3 to 4 cm flowers are white with a pink tinge that gradually fades, five petaled, with an inflorescence consisting of a cyme with 4–6 flowers. The central flower of the inflorescence is called the king bloom, it opens first, the fruit matures in late summer or autumn, and cultivars exist with a wide range of sizes. Commercial growers aim to produce an apple that is 7.0 to 8.3 cm in diameter, due to market preference. Some consumers, especially those in Japan, prefer a larger apple, while apples below 5.7 cm are generally used for making juice and have little market value. The skin of ripe apples is generally red, yellow, green, pink, the skin may also be wholly or partly russeted i. e. rough and brown. The skin is covered in a layer of epicuticular wax. The exocarp is generally pale yellowish-white, though pink or yellow also occur. The original wild ancestor of Malus pumila was Malus sieversii, found growing wild in the mountains of Central Asia in southern Kazakhstan, Kyrgyzstan, Tajikistan, in strains without recent admixture the contribution of the latter predominates. It had about 57,000 genes, the highest number of any plant genome studied to date and this new understanding of the apple genome will help scientists in identifying genes and gene variants that contribute to resistance to disease and drought, and other desirable characteristics
34.
Peach
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The peach is a deciduous tree native to the region of Northwest China between the Tarim Basin and the north slopes of the Kunlun Shan mountains, where it was first domesticated and cultivated. It bears an edible fruit called a peach or a nectarine. The specific epithet refers to its widespread cultivation in Persia. It belongs to the genus Prunus which includes the cherry, apricot, almond and plum, the peach is classified with the almond in the subgenus Amygdalus, distinguished from the other subgenera by the corrugated seed shell. Peach and nectarines are the species, even though they are regarded commercially as different fruits. The Peoples Republic of China is the worlds largest producer of peaches, Prunus persica grows to 4–10 m tall and 6 in. in diameter. The leaves are lanceolate, 7–16 cm long, 2–3 cm broad, the flowers are produced in early spring before the leaves, they are solitary or paired,2. 5–3 cm diameter, pink, with five petals. The fruit has yellow or whitish flesh, an aroma. The flesh is very delicate and easily bruised in some cultivars, the single, large seed is red-brown, oval shaped, approximately 1. 3–2 cm long, and is surrounded by a wood-like husk. Peaches, along with cherries, plums and apricots, are stone fruits, there are various heirloom varieties, including the Indian peach, which arrives in the latter part of the summer. Cultivated peaches are divided into clingstones and freestones, depending on whether the flesh sticks to the stone or not, Peaches with white flesh typically are very sweet with little acidity, while yellow-fleshed peaches typically have an acidic tang coupled with sweetness, though this also varies greatly. Both colors often have red on their skin. The scientific name persica, along with the word peach itself, the Ancient Romans referred to the peach as malum persicum Persian apple, later becoming French pêche, hence the English peach. The scientific name, Prunus persica, literally means Persian plum, fossil endocarps with characteristics indistinguishable from those of modern peaches have been recovered from late Pliocene deposits in Kunming, dating to 2.6 million years ago. In the absence of evidence that the plants were in other ways identical to the modern peach, until recently, it was believed that the cultivation started circa 2000 BC. Nevertheless, the recent evidence indicates that domestication occurred as early as 6000 BC in Zhejiang Province of China, the oldest archaeological peach stones are from the Kuahuqiao site. Archaeologists point at the Yangzi River valley as the place where the selection for favorable peach varieties likely took place. Peaches were mentioned in Chinese writings as far back as the 10th century BC and were a fruit of kings
35.
Sugar
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Sugar is the generic name for sweet, soluble carbohydrates, many of which are used in food. There are various types of derived from different sources. Simple sugars are called monosaccharides and include glucose, fructose, the table sugar or granulated sugar most customarily used as food is sucrose, a disaccharide of glucose and fructose. Sugar is used in prepared foods and it is added to some foods, in the body, sucrose is hydrolysed into the simple sugars fructose and glucose. Other disaccharides include maltose from malted grain, and lactose from milk, longer chains of sugars are called oligosaccharides or polysaccharides. Some other chemical substances, such as glycerol may also have a sweet taste, low-calorie food substitutes for sugar, described as artificial sweeteners, include aspartame and sucralose, a chlorinated derivative of sucrose. Sugars are found in the tissues of most plants and are present in sufficient concentrations for efficient commercial extraction in sugarcane, the world production of sugar in 2011 was about 168 million tonnes. The average person consumes about 24 kilograms of sugar each year, equivalent to over 260 food calories per person, since the latter part of the twentieth century, it has been questioned whether a diet high in sugars, especially refined sugars, is good for human health. Sugar has been linked to obesity, and suspected of, or fully implicated as a cause in the occurrence of diabetes, cardiovascular disease, dementia, macular degeneration, the etymology reflects the spread of the commodity. The English word sugar ultimately originates from the Sanskrit शर्करा, via Arabic سكر as granular or candied sugar, the contemporary Italian word is zucchero, whereas the Spanish and Portuguese words, azúcar and açúcar, respectively, have kept a trace of the Arabic definite article. The Old French word is zuchre and the contemporary French, sucre, the earliest Greek word attested is σάκχαρις. The English word jaggery, a brown sugar made from date palm sap or sugarcane juice, has a similar etymological origin – Portuguese jagara from the Sanskrit शर्करा. Sugar has been produced in the Indian subcontinent since ancient times and it was not plentiful or cheap in early times and honey was more often used for sweetening in most parts of the world. Originally, people chewed raw sugarcane to extract its sweetness, sugarcane was a native of tropical South Asia and Southeast Asia. Different species seem to have originated from different locations with Saccharum barberi originating in India and S. edule, one of the earliest historical references to sugarcane is in Chinese manuscripts dating back to 8th century BC that state that the use of sugarcane originated in India. Sugar was found in Europe by the 1st century AD, but only as an imported medicine and it is a kind of honey found in cane, white as gum, and it crunches between the teeth. It comes in lumps the size of a hazelnut, sugar is used only for medical purposes. Sugar remained relatively unimportant until the Indians discovered methods of turning sugarcane juice into granulated crystals that were easier to store, crystallized sugar was discovered by the time of the Imperial Guptas, around the 5th century AD
36.
Glycoside
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In chemistry, a glycoside /ˈɡlaɪkəsaɪd/ is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms, many plants store chemicals in the form of inactive glycosides. These can be activated by enzyme hydrolysis, which causes the part to be broken off. Many such plant glycosides are used as medications, in animals and humans, poisons are often bound to sugar molecules as part of their elimination from the body. In formal terms, a glycoside is any molecule in which a group is bonded through its anomeric carbon to another group via a glycosidic bond. Glycosides can be linked by an O-, N-, S-, according to the IUPAC, the name C-glycoside is a misnomer, the preferred term is C-glycosyl compound. The given definition is the one used by IUPAC, which recommends the Haworth projection to correctly assign stereochemical configurations, many authors require in addition that the sugar be bonded to a non-sugar for the molecule to qualify as a glycoside, thus excluding polysaccharides. The sugar group is known as the glycone and the non-sugar group as the aglycone or genin part of the glycoside. The glycone can consist of a sugar group or several sugar groups. The first glycoside ever identified was amygdalin, by the French chemists Pierre Robiquet and Antoine Boutron-Charlard, molecules containing an N-glycosidic bond are known as glycosylamines and are not discussed in this article. Glycosylamines and glycosides are grouped together as glycoconjugates, other glycoconjugates include glycoproteins, glycopeptides, peptidoglycans, glycolipids, much of the chemistry of glycosides is explained in the article on glycosidic bonds. For example, the glycone and aglycone portions can be separated by hydrolysis in the presence of acid. There are also numerous enzymes that can form and break glycosidic bonds, the most important cleavage enzymes are the glycoside hydrolases, and the most important synthetic enzymes in nature are glycosyltransferases. Genetically altered enzymes termed glycosynthases have been developed that can form glycosidic bonds in excellent yield, there are many ways to chemically synthesize glycosidic bonds. Fischer glycosidation refers to the synthesis of glycosides by the reaction of unprotected monosaccharides with alcohols in the presence of an acid catalyst. The Koenigs-Knorr reaction is the condensation of glycosyl halides and alcohols in the presence of salts such as silver carbonate or mercuric oxide. Glycosides can be classified by the glycone, by the type of glycosidic bond, in the body, toxic substances are often bonded to glucuronic acid to increase their water solubility, the resulting glucuronides are then excreted. Depending on whether the glycosidic bond lies below or above the plane of the sugar molecule
37.
Herbivore
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A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthparts adapted to rasping or grinding, horses and other herbivores have wide flat teeth that are adapted to grinding grass, tree bark, and other tough plant material. A large percentage of herbivores have mutualistic gut flora that help them digest plant matter and this gut flora is made up of cellulose-digesting protozoans or bacteria living in the herbivores intestines. Herbivore is the form of a modern Latin coinage, herbivora. Richard Owen employed the term in an 1854 work on fossil teeth. Herbivora is derived from the Latin herba meaning a small plant or herb, Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms feed on autotrophs in general are known as primary consumers. Herbivory usually refers to eating plants, fungi, bacteria and protists that feed on living plants are usually termed plant pathogens. Flowering plants that obtain nutrition from other living plants are usually termed parasitic plants, there is however no single exclusive and definitive ecological classification of consumption patterns, each textbook has its own variations on the theme. Insects fed on the spores of early Devonian plants, and the Rhynie chert also provides evidence that organisms fed on plants using a pierce, during the next 75 million years, plants evolved a range of more complex organs, such as roots and seeds. There is no evidence of any organism being fed upon until the middle-late Mississippian,330.9 million years ago, further than their arthropod status, the identity of these early herbivores is uncertain. Hole feeding and skeletonisation are recorded in the early Permian, with surface fluid feeding evolving by the end of that period, Herbivory among four-limbed terrestrial vertebrates, the tetrapods developed in the Late Carboniferous. Early tetrapods were large amphibious piscivores, while amphibians continued to feed on fish and insects, some reptiles began exploring two new food types, tetrapods and plants. The entire dinosaur order ornithischia was composed with herbivores dinosaurs, carnivory was a natural transition from insectivory for medium and large tetrapods, requiring minimal adaptation. In contrast, a set of adaptations was necessary for feeding on highly fibrous plant materials. Arthropods evolved herbivory in four phases, changing their approach to it in response to changing plant communities, tetrapod herbivores made their first appearance in the fossil record of their jaws near the Permio-Carboniferous boundary, approximately 300 million years ago. The earliest evidence of their herbivory has been attributed to dental occlusion, the evolution of dental occlusion led to a drastic increase in plant food processing and provides evidence about feeding strategies based on tooth wear patterns. Examination of phylogenetic frameworks of tooth and jaw morphologes has revealed that dental occlusion developed independently in several lineages tetrapod herbivores and this suggests that evolution and spread occurred simultaneously within various lineages
38.
Potato
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The potato is a starchy, tuberous crop from the perennial nightshade Solanum tuberosum. The word potato may refer either to the plant itself or to the edible tuber, in the Andes, where the species is indigenous, there are some other closely related cultivated potato species. Potatoes were introduced to Europe in the half of the 16th century by the Spanish. It is the worlds fourth-largest food crop, following maize, wheat, the green leaves and green skins of tubers exposed to the light are toxic. Wild potato species can be throughout the Americas from the United States to southern Chile. Following centuries of breeding, there are now over a thousand different types of potatoes. However, the importance of the potato is variable and changing rapidly. As of 2007 China led the world in production, and nearly a third of the worlds potatoes were harvested in China. The English word potato comes from Spanish patata, the Spanish Royal Academy says the Spanish word is a compound of the Taíno batata and the Quechua papa. The 16th-century English herbalist John Gerard used the terms bastard potatoes and Virginia potatoes for this species, potatoes are occasionally referred to as Irish potatoes or white potatoes in the United States, to distinguish them from sweet potatoes. The name spud for a small potato comes from the digging of soil prior to the planting of potatoes, the word spud traces back to the 16th century. It subsequently transferred over to a variety of digging tools, around 1845, the name transferred to the tuber itself. It was Mario Peis 1949 The Story of Language that can be blamed for the false origin. Pei writes, the potato, for its part, was in disrepute some centuries ago, some Englishmen who did not fancy potatoes formed a Society for the Prevention of Unwholesome Diet. The initials of the words in this title gave rise to spud. Like most other pre-20th century acronymic origins, this is false, Potato plants are herbaceous perennials that grow about 60 cm high, depending on variety, with the leaves dying back after flowering, fruiting and tuber formation. They bear white, pink, red, blue, or purple flowers with yellow stamens, in general, the tubers of varieties with white flowers have white skins, while those of varieties with colored flowers tend to have pinkish skins. Potatoes are mostly cross-pollinated by insects such as bumblebees, which carry pollen from other potato plants, tubers form in response to decreasing day length, although this tendency has been minimized in commercial varieties
39.
Tapioca
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Tapioca is a starch extracted from cassava root. This species is native to the North Region of Brazil but spread throughout South America, the plant was carried by Portuguese and Spanish explorers to most of the West Indies, and the continents of Africa and Asia, including the Philippines and Taiwan. Its a shrubby, tropical, perennial plant that is common in the temperate zone. Tapioca thrives better in poor soils than any other major food plant, as a result, fertilization is rarely necessary Around the world, Tapioca is a vital staple food for about 500 million people. Tapiocas starchy roots produce more energy per unit of land than any other staple crop. Its leaves, commonly eaten as a vegetable in parts of Asia and Africa, provide vitamins, nutritionally, the Tapioca is comparable to potatoes, except that it has twice the fiber content and a higher level of potassium. Its used as an agent in various foods. Tapioca is derived from the word tipióka, its name in the Tupí language spoken by natives when the Portuguese first arrived in the Northeast Region of Brazil around 1707 and this Tupí word refers to the process by which the cassava starch is made edible. Tapioca is one of the purest forms of food. The cassava plant has red or green branches with blue spindles on them. The root of the green-branched variant requires treatment to remove linamarin, a cyanogenic glycoside occurring naturally in the plant, konzo is a paralytic disease associated with several weeks of almost exclusive consumption of insufficiently processed bitter cassava. In the north and northeast of Brazil, traditional community-based production of tapioca is a by-product of manioc flour production from cassava roots, in this process, the manioc is ground to a pulp with a small hand- or diesel-powered mill. This masa is then squeezed to dry it out, the wet masa is placed in a long woven tube called a tipiti. This liquid is collected and the water allowed to evaporate, leaving behind a fine-grained tapioca powder similar in appearance to corn starch, commercially, the starch is processed into several forms, hot soluble powder, meal, pre-cooked fine/coarse flakes, rectangular sticks, and spherical pearls. Pearls are the most widely available shape, sizes range from about 1 mm to 8 mm in diameter, flakes, sticks, and pearls must be soaked well before cooking, in order to rehydrate, absorbing water up to twice their volume. After rehydration, tapioca products become leathery and swollen, processed tapioca is usually white, but sticks and pearls may be colored. Traditionally, the most common color applied to tapioca has been brown, Tapioca pearls are generally opaque when raw, but become translucent when cooked in boiling water. Brazil in South America, Thailand in Asia, and Nigeria in Africa are the worlds largest producers of cassava, currently, Thailand accounts for about 60 percent of worldwide exports
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Madagascar
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Madagascar, officially the Republic of Madagascar, and previously known as the Malagasy Republic, is an island country in the Indian Ocean, off the coast of Southeast Africa. The nation comprises the island of Madagascar, and numerous smaller peripheral islands, consequently, Madagascar is a biodiversity hotspot, over 90% of its wildlife is found nowhere else on Earth. The islands diverse ecosystems and unique wildlife are threatened by the encroachment of the growing human population. The first archaeological evidence for human foraging on Madagascar dates to 2000 BC, human settlement of Madagascar occurred between 350 BC and AD550 by Austronesian peoples arriving on outrigger canoes from Borneo. These were joined around AD1000 by Bantu migrants crossing the Mozambique Channel from East Africa, other groups continued to settle on Madagascar over time, each one making lasting contributions to Malagasy cultural life. The Malagasy ethnic group is divided into 18 or more sub-groups of which the largest are the Merina of the central highlands. Until the late 18th century, the island of Madagascar was ruled by an assortment of shifting sociopolitical alliances. Beginning in the early 19th century, most of the island was united and ruled as the Kingdom of Madagascar by a series of Merina nobles, the monarchy collapsed in 1897 when the island was absorbed into the French colonial empire, from which the island gained independence in 1960. The autonomous state of Madagascar has since undergone four major constitutional periods, since 1992, the nation has officially been governed as a constitutional democracy from its capital at Antananarivo. However, in an uprising in 2009, president Marc Ravalomanana was made to resign. Constitutional governance was restored in January 2014, when Hery Rajaonarimampianina was named president following a 2013 election deemed fair, Madagascar is a member of the United Nations, the Organisation Internationale de la Francophonie and the Southern African Development Community. Madagascar belongs to the group of least developed countries, according to the United Nations, Malagasy and French are both official languages of the state. The majority of the population adheres to traditional beliefs, Christianity, ecotourism and agriculture, paired with greater investments in education, health, and private enterprise, are key elements of Madagascars development strategy. As of 2017, the economy has been weakened by the 2009-2013 political crisis, in the Malagasy language, the island of Madagascar is called Madagasikara and its people are referred to as Malagasy. The islands appellation Madagascar is not of origin, but rather was popularized in the Middle Ages by Europeans. On St. Laurences Day in 1500, Portuguese explorer Diogo Dias landed on the island, polos name was preferred and popularized on Renaissance maps. At 592,800 square kilometres, Madagascar is the worlds 47th largest country, the country lies mostly between latitudes 12°S and 26°S, and longitudes 43°E and 51°E. Neighboring islands include the French territory of Réunion and the country of Mauritius to the east, as well as the state of Comoros, the nearest mainland state is Mozambique, located to the west
. PMID 19868035. Retrieved 2008-06-28.
