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Alloy The introduction of the blast furnace to Europe in the Middle Ages meant that people could produce pig iron in much higher volumes than wrought iron. Because pig iron could be melted, people began to develop processes to reduce carbon in liquid pig iron to create steel. Puddling had been used in China since the f... | https://en.wikipedia.org/wiki?curid=1187 |
Alloy Thus, almost no metallurgical information existed about steel until 1860. Because of this lack of understanding, steel was not generally considered an alloy until the decades between 1930 and 1970 (primarily due to the work of scientists like William Chandler Roberts-Austen, Adolf Martens, and Edgar Bain), so "al... | https://en.wikipedia.org/wiki?curid=1187 |
Alloy Mushet's steel was quickly replaced by tungsten carbide steel, developed by Taylor and White in 1900, in which they doubled the tungsten content and added small amounts of chromium and vanadium, producing a superior steel for use is lathes and machining tools. In 1903 the Wright brothers used a chromium-nickel st... | https://en.wikipedia.org/wiki?curid=1187 |
Alloy His work eventually led to the periodic table of elements, which helped confirm the existence of these "missing metals." Due to their high reactivity, most metals were not discovered until the 19th century. A method for extracting aluminium from bauxite was proposed by Humphry Davy in 1807, using an electric arc.... | https://en.wikipedia.org/wiki?curid=1187 |
Alloy However, as the aircraft and automotive industries began growing, research into alloys became an industrial effort in the years following 1910, as new magnesium alloys were developed for pistons and wheels in cars, and pot metal for levers and knobs, and aluminium alloys developed for airframes and aircraft skins... | https://en.wikipedia.org/wiki?curid=1187 |
Allotropy or allotropism () is the property of some chemical elements to exist in two or more different forms, in the same physical state, known as allotropes of the elements. Allotropes are different structural modifications of an element; the atoms of the element are bonded together in a different manner. For example... | https://en.wikipedia.org/wiki?curid=1839 |
Allotropy The term is derived . After the acceptance of Avogadro's hypothesis in 1860, it was understood that elements could exist as polyatomic molecules, and two allotropes of oxygen were recognized as O and O. In the early 20th century, it was recognized that other cases such as carbon were due to differences in cry... | https://en.wikipedia.org/wiki?curid=1839 |
Allotropy Typically, elements capable of variable coordination number and/or oxidation states tend to exhibit greater numbers of allotropic forms. Another contributing factor is the ability of an element to catenate. Examples of allotropes include: Among the metallic elements that occur in nature in significant quantit... | https://en.wikipedia.org/wiki?curid=1839 |
Acid–base reaction An acid–base reaction is a chemical reaction that occurs between an acid and a base. It can be used to determine pH. Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their application in solving related problems; these are called the acid–base theories, fo... | https://en.wikipedia.org/wiki?curid=3038 |
Acid–base reaction The Lavoisier definition held for over 30 years, until the 1810 article and subsequent lectures by Sir Humphry Davy in which he proved the lack of oxygen in , HTe, and the hydrohalic acids. However, Davy failed to develop a new theory, concluding that "acidity does not depend upon any particular elem... | https://en.wikipedia.org/wiki?curid=3038 |
Acid–base reaction Thus, in modern times, the symbol H is interpreted as a shorthand for HO, because it is now known that a bare proton does not exist as a free species in aqueous solution. The Arrhenius definitions of acidity and alkalinity are restricted to aqueous solutions, and refer to the concentration of the sol... | https://en.wikipedia.org/wiki?curid=3038 |
Acid–base reaction Though all three substances, HCl, NaOH and NaCl are capable of existing as pure compounds, in aqueous solutions they are fully dissociated into the aquated ions H, Cl, Na and OH. The Brønsted–Lowry definition, formulated in 1923, independently by Johannes Nicolaus Brønsted in Denmark and Martin Lowry... | https://en.wikipedia.org/wiki?curid=3038 |
Acid–base reaction Brønsted–Lowry acid–base behavior is formally independent of any solvent, making it more all-encompassing than the Arrhenius model. The calculation of pH under the Arrhenius model depended on alkalis (bases) dissolving in water (aqueous solution). The Brønsted–Lowry model expanded what could be pH te... | https://en.wikipedia.org/wiki?curid=3038 |
Acid–base reaction In this example, a water molecule is split into a hydrogen ion, which is donated to a pyridine molecule, and an hydroxide ion. In the Brønsted-Lowry model, the solvent does not necessarily have to be water that is required by the Arrhenius Acid-Base model. For example, consider what happens when acet... | https://en.wikipedia.org/wiki?curid=3038 |
Acid–base reaction Instead of defining acid–base reactions in terms of protons or other bonded substances, the Lewis definition defines a base (referred to as a "Lewis base") to be a compound that can donate an "electron pair", and an acid (a "Lewis acid") to be a compound that can receive this electron pair. For examp... | https://en.wikipedia.org/wiki?curid=3038 |
Acid–base reaction The reaction can be seen as an acid–base reaction in which a stronger base (ammonia) replaces a weaker one (water) The Lewis and Brønsted–Lowry definitions are consistent with each other since the reaction is an acid–base reaction in both theories. One of the limitations of the Arrhenius definition i... | https://en.wikipedia.org/wiki?curid=3038 |
Acid–base reaction In liquid sulfur dioxide (), thionyl compounds (supplying ) behave as acids, and sulfites (supplying ) behave as bases. The non-aqueous acid–base reactions in liquid ammonia are similar to the reactions in water: Nitric acid can be a base in liquid sulfuric acid: The unique strength of this definitio... | https://en.wikipedia.org/wiki?curid=3038 |
Acid–base reaction For example: This theory is also useful in the systematisation of the reactions of noble gas compounds, especially the xenon oxides, fluorides, and oxofluorides. Mikhail Usanovich developed a general theory that does not restrict acidity to hydrogen-containing compounds, but his approach, published i... | https://en.wikipedia.org/wiki?curid=3038 |
Acid–base reaction The "E" and "C" parameters refer, respectively, to the electrostatic and covalent contributions to the strength of the bonds that the acid and base will form. The equation is The "W" term represents a constant energy contribution for acid–base reaction such as the cleavage of a dimeric acid or base. ... | https://en.wikipedia.org/wiki?curid=3038 |
Acid–base reaction When an acid reacts with an alkali salt (a metal hydroxide), the product is a metal salt and water. Acid–alkali reactions are also neutralization reactions. In general, acid–alkali reactions can be simplified to by omitting spectator ions. Acids are in general pure substances that contain hydrogen ca... | https://en.wikipedia.org/wiki?curid=3038 |
Afterglow An afterglow is a broad arch of whitish or pinkish sunlight in the sky that is scattered by fine particulates, like dust, suspended in the atmosphere. An afterglow may appear above the highest clouds in the hour of fading twilight or be reflected off high snowfields in mountain regions long after sunset. The ... | https://en.wikipedia.org/wiki?curid=3124 |
Afterglow After the 1883 eruption of the volcano Krakatoa, a remarkable series of red sunsets appeared worldwide. An enormous amount of exceedingly fine dust were blown to a great height by the volcano's explosion, and then globally diffused by the high atmospheric winds. Edvard Munch's painting "The Scream" possibly d... | https://en.wikipedia.org/wiki?curid=3124 |
Biochemistry Biochemistry, sometimes called biological chemistry, is the study of chemical processes within and relating to living organisms. Biochemical processes give rise to the complexity of life. A sub-discipline of both biology and chemistry, biochemistry can be divided into three fields; structural biology, enzy... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry The mechanisms by which cells harness energy from their environment via chemical reactions are known as metabolism. The findings of biochemistry are applied primarily in medicine, nutrition, and agriculture. In medicine, biochemists investigate the causes and cures of diseases. In nutrition, they study how... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry Some might also point as its beginning to the influential 1842 work by Justus von Liebig, "Animal chemistry, or, Organic chemistry in its applications to physiology and pathology", which presented a chemical theory of metabolism, or even earlier to the 18th century studies on fermentation and respiration b... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry Then, in 1828, Friedrich Wöhler published a paper on the synthesis of urea, proving that organic compounds can be created artificially. Since then, biochemistry has advanced, especially since the mid-20th century, with the development of new techniques such as chromatography, X-ray diffraction, dual polari... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry More recently, Andrew Z. Fire and Craig C. Mello received the 2006 Nobel Prize for discovering the role of RNA interference (RNAi), in the silencing of gene expression. Around two dozen chemical elements are essential to various kinds of biological life. Most rare elements on Earth are not needed by life (... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry Different macromolecules can assemble in larger complexes, often needed for biological activity. Two of the main functions of carbohydrates are energy storage and providing structure. Sugars are carbohydrates, but not all carbohydrates are sugars. There are more carbohydrates on Earth than any other known ... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry For example, the aldohexose glucose may form a hemiacetal linkage between the hydroxyl on carbon 1 and the oxygen on carbon 4, yielding a molecule with a 5-membered ring, called glucofuranose. The same reaction can take place between carbons 1 and 5 to form a molecule with a 6-membered ring, called glucopy... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry "Cellulose" is an important structural component of plant's cell walls and "glycogen" is used as a form of energy storage in animals. Sugar can be characterized by having reducing or non-reducing ends. A reducing end of a carbohydrate is a carbon atom that can be in equilibrium with the open-chain aldehyde... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry Lipids are usually made from one molecule of glycerol combined with other molecules. In triglycerides, the main group of bulk lipids, there is one molecule of glycerol and three fatty acids. Fatty acids are considered the monomer in that case, and may be saturated (no double bonds in the carbon chain) or u... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry , in parenteral infusions) or else as drug carrier components (e.g., in a liposome or transfersome). Proteins are very large molecules—macro-biopolymers—made from monomers called amino acids. An amino acid consists of an alpha carbon atom attached to an amino group, –NH, a carboxylic acid group, –COOH (alt... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry One property many proteins have is that they specifically bind to a certain molecule or class of molecules—they may be "extremely" selective in what they bind. Antibodies are an example of proteins that attach to one specific type of molecule. Antibodies are composed of heavy and light chains. Two heavy ch... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry The primary structure of a protein consists of its linear sequence of amino acids; for instance, "alanine-glycine-tryptophan-serine-glutamate-asparagine-glycine-lysine-…". Secondary structure is concerned with local morphology (morphology being the study of structure). Some combinations of amino acids will... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry They cannot synthesize isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Because they must be ingested, these are the essential amino acids. Mammals do possess the enzymes to synthesize alanine, asparagine, aspartate, cysteine, glutamate, glutamine, glycine, proline... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry Likewise, bony fish can release the ammonia into the water where it is quickly diluted. In general, mammals convert the ammonia into urea, via the urea cycle. In order to determine whether two proteins are related, or in other words to decide whether they are homologous or not, scientists use sequence-comp... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry The nitrogenous bases of each strand of a nucleic acid will form hydrogen bonds with certain other nitrogenous bases in a complementary strand of nucleic acid (similar to a zipper). Adenine binds with thymine and uracil, thymine binds only with adenine, and cytosine and guanine can bind only with one anoth... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry This does not require oxygen; if no oxygen is available (or the cell cannot use oxygen), the NAD is restored by converting the pyruvate to lactate (lactic acid) (e.g., in humans) or to ethanol plus carbon dioxide (e.g., in yeast). Other monosaccharides like galactose and fructose can be converted into inte... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry This generates an additional "28" molecules of ATP (24 from the 8 NADH + 4 from the 2 quinols), totaling to 32 molecules of ATP conserved per degraded glucose (two from glycolysis + two from the citrate cycle). It is clear that using oxygen to completely oxidize glucose provides an organism with far more e... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry Analogous to the above reactions, the glucose produced can then undergo glycolysis in tissues that need energy, be stored as glycogen (or starch in plants), or be converted to other monosaccharides or joined into di- or oligosaccharides. The combined pathways of glycolysis during exercise, lactate's crossi... | https://en.wikipedia.org/wiki?curid=3954 |
Biochemistry The DNA polimerase of the thermophile bacteria "Thermus aquaticus", extracted in 1968 and named "Taq" polymerase, is a biochemical DNA replicator resistant to relative high temperatures (50-80 °C), which has allowed molecular biologists to ease complications in the PCR (Polymerase Chain Reaction) method. a... | https://en.wikipedia.org/wiki?curid=3954 |
Bioleaching is the extraction of metals from their ores through the use of living organisms. This is much cleaner than the traditional heap leaching using cyanide. is one of several applications within biohydrometallurgy and several methods are used to recover copper, zinc, lead, arsenic, antimony, nickel, molybdenum, ... | https://en.wikipedia.org/wiki?curid=4111 |
Bioleaching Pyrite leaching (FeS): In the first step, disulfide is spontaneously oxidized to thiosulfate by ferric ion (Fe), which in turn is reduced to give ferrous ion (Fe): The ferrous ion is then oxidized by bacteria using oxygen: Thiosulfate is also oxidized by bacteria to give sulfate: The ferric ion produced in ... | https://en.wikipedia.org/wiki?curid=4111 |
Bioleaching Chalcopyrite leaching: net reaction: In general, sulfides are first oxidized to elemental sulfur, whereas disulfides are oxidized to give thiosulfate, and the processes above can be applied to other sulfidic ores. of non-sulfidic ores such as pitchblende also uses ferric iron as an oxidant (e.g., UO + 2 Fe ... | https://en.wikipedia.org/wiki?curid=4111 |
Bioleaching Adding concentrated acid reverses the equation, and the copper ions go back into an aqueous solution. Then the copper is passed through an electro-winning process to increase its purity: An electric current is passed through the resulting solution of copper ions. Because copper ions have a 2+ charge, they a... | https://en.wikipedia.org/wiki?curid=4111 |
Bioleaching Extractions involve many expensive steps such as roasting, pressure oxidation, and smelting, which require sufficient concentrations of elements in ores and are environmentally unfriendly. Low concentrations are not a problem for bacteria because they simply ignore the waste that surrounds the metals, attai... | https://en.wikipedia.org/wiki?curid=4111 |
Bacteriophage A bacteriophage (), also known informally as a phage (), is a virus that infects and replicates within bacteria and archaea. The term was derived from "bacteria" and the Greek φαγεῖν (""), meaning "to devour". Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have struc... | https://en.wikipedia.org/wiki?curid=4185 |
Bacteriophage Bacteriophages occur abundantly in the biosphere, with different genomes, and lifestyles. Phages are classified by the International Committee on Taxonomy of Viruses (ICTV) according to morphology and nucleic acid. Nineteen families are currently recognized by the ICTV that infect bacteria and archaea. Of... | https://en.wikipedia.org/wiki?curid=4185 |
Bacteriophage Independently, French-Canadian microbiologist Félix d'Hérelle, working at the Pasteur Institute in Paris, announced on 3 September 1917, that he had discovered "an invisible, antagonistic microbe of the dysentery bacillus". For d’Hérelle, there was no question as to the nature of his discovery: "In a flas... | https://en.wikipedia.org/wiki?curid=4185 |
Bacteriophage The first regulated, randomized, double-blind clinical trial was reported in the Journal of Wound Care in June 2009, which evaluated the safety and efficacy of a bacteriophage cocktail to treat infected venous ulcers of the leg in human patients. The FDA approved the study as a Phase I clinical trial. The... | https://en.wikipedia.org/wiki?curid=4185 |
Bacteriophage There have been results showing that T4 phages that are small in size and short-tailed, can be helpful in detecting "E.coli" in the human body. Therapeutic efficacy of a phage cocktail was evaluated in a mice model with nasal infection of multidrug-resistant (MDR) "A. baumannii". Mice treated with the pha... | https://en.wikipedia.org/wiki?curid=4185 |
Bacteriophage In that same year, the FDA approved LISTEX (developed and produced by Micreos) using bacteriophages on cheese to kill "Listeria monocytogenes" bacteria, in order to give them generally recognized as safe (GRAS) status. In July 2007, the same bacteriophage were approved for use on all food products. In 201... | https://en.wikipedia.org/wiki?curid=4185 |
Bacteriophage Counteracting bioweapons and toxins – Government agencies in the West have for several years been looking to Georgia and the former Soviet Union for help with exploiting phages for counteracting bioweapons and toxins, such as anthrax and botulism. Developments are continuing among research groups in the U... | https://en.wikipedia.org/wiki?curid=4185 |
Bacteriophage The bound, selected phages can be multiplied by reinfecting a susceptible bacterial strain, thus allowing them to retrieve the peptides encoded in them for further study. Antimicrobial drug discovery - Phage proteins often have antimicrobial activity and may serve as leads for peptidomimetics, i.e. drugs ... | https://en.wikipedia.org/wiki?curid=4185 |
Bacteriophage The virus remains dormant until host conditions deteriorate, perhaps due to depletion of nutrients, then, the endogenous phages (known as prophages) become active. At this point they initiate the reproductive cycle, resulting in lysis of the host cell. As the lysogenic cycle allows the host cell to contin... | https://en.wikipedia.org/wiki?curid=4185 |
Bacteriophage Polysaccharide-degrading enzymes, like endolysins are virion-associated proteins to enzymatically degrade the capsular outer layer of their hosts, at the initial step of a tightly programmed phage infection process. Host growth conditions also influence the ability of the phage to attach and invade them. ... | https://en.wikipedia.org/wiki?curid=4185 |
Bacteriophage Proteins modify the bacterial RNA polymerase so it preferentially transcribes viral mRNA. The host's normal synthesis of proteins and nucleic acids is disrupted, and it is forced to manufacture viral products instead. These products go on to become part of new virions within the cell, helper proteins that... | https://en.wikipedia.org/wiki?curid=4185 |
Bacteriophage Budding is associated with certain "Mycoplasma" phages. In contrast to virion release, phages displaying a lysogenic cycle do not kill the host but, rather, become long-term residents as prophage. Research in 2017 revealed that the bacteriophage Φ3T makes a short viral protein that signals other bacteriop... | https://en.wikipedia.org/wiki?curid=4185 |
Bacteriophage Evolutionary mechanisms shaping the genomes of bacterial viruses vary between different families and depend upon the type of the nucleic acid, characteristics of the virion structure, as well as the mode of the viral life cycle. Phages often have dramatic effects on their hosts. As a consequence, the tran... | https://en.wikipedia.org/wiki?curid=4185 |
Bacteriophage The use of phages is preferred to the more conventional dye marker because they are significantly less absorbed when passing through ground waters and they are readily detected at very low concentrations. Non-polluted water may contain approximately 2×10 bacteriophages per ml. Bacteriophages are thought t... | https://en.wikipedia.org/wiki?curid=4185 |
Bacterial conjugation is the transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells. This takes place through a pilus. It is a mechanism of horizontal gene transfer as are transformation and transduction although these two other mechanisms do... | https://en.wikipedia.org/wiki?curid=4460 |
Bacterial conjugation coli" conjugation in that these cases involve substantial blending of the parental genomes. The process was discovered by Joshua Lederberg and Edward Tatum in 1946. Conjugation diagram The F-plasmid is an episome (a plasmid that can integrate itself into the bacterial chromosome by homologous reco... | https://en.wikipedia.org/wiki?curid=4460 |
Bacterial conjugation Several proteins coded for in the "tra" or "trb" locus seem to open a channel between the bacteria and it is thought that the traD enzyme, located at the base of the pilus, initiates membrane fusion. When conjugation is initiated by a signal the relaxase enzyme creates a nick in one of the strands... | https://en.wikipedia.org/wiki?curid=4460 |
Bacterial conjugation The amount of chromosomal DNA that is transferred depends on how long the two conjugating bacteria remain in contact. In common laboratory strains of "E. coli" the transfer of the entire bacterial chromosome takes about 100 minutes. The transferred DNA can then be integrated into the recipient gen... | https://en.wikipedia.org/wiki?curid=4460 |
Bacterial conjugation Spontaneous zygogenesis in "E. coli" In addition to classical bacterial conjugation described above for "E. coli", a form of conjugation referred to as spontaneous zygogenesis (Z-mating for short) is observed in certain strains of "E. coli". In Z-mating there is complete genetic mixing, and unstab... | https://en.wikipedia.org/wiki?curid=4460 |
Bacterial conjugation For example, the tumor-inducing (Ti) plasmid of "Agrobacterium" and the root-tumor inducing (Ri) plasmid of "A. rhizogenes" contain genes that are capable of transferring to plant cells. The expression of these genes effectively transforms the plant cells into opine-producing factories. Opines are... | https://en.wikipedia.org/wiki?curid=4460 |
Bacterial conjugation While TMV is capable of infecting many plant families these are primarily herbaceous dicots. "Agrobacterium"-like conjugation is also primarily used for dicots, but monocot recipients are not uncommon. | https://en.wikipedia.org/wiki?curid=4460 |
Biotechnology is the broad area of biology, involving living systems and organisms to develop or make products. Depending on the tools and applications, it often overlaps with related scientific fields. In the late 20th and early 21st centuries, biotechnology has expanded to include new and diverse sciences, such as ge... | https://en.wikipedia.org/wiki?curid=4502 |
Biotechnology is the research and development in the laboratory using bioinformatics for exploration, extraction, exploitation and production from any living organisms and any source of biomass by means of biochemical engineering where high value-added products could be planned (reproduced by biosynthesis, for example)... | https://en.wikipedia.org/wiki?curid=4502 |
Biotechnology Relatedly, biomedical engineering is an overlapping field that often draws upon and applies "biotechnology" (by various definitions), especially in certain sub-fields of biomedical or chemical engineering such as tissue engineering, biopharmaceutical engineering, and genetic engineering. Although not norm... | https://en.wikipedia.org/wiki?curid=4502 |
Biotechnology In brewing, malted grains (containing enzymes) convert starch from grains into sugar and then adding specific yeasts to produce beer. In this process, carbohydrates in the grains broke down into alcohols, such as ethanol. Later, other cultures produced the process of lactic acid fermentation, which produc... | https://en.wikipedia.org/wiki?curid=4502 |
Biotechnology In 1917, Chaim Weizmann first used a pure microbiological culture in an industrial process, that of manufacturing corn starch using "Clostridium acetobutylicum," to produce acetone, which the United Kingdom desperately needed to manufacture explosives during World War I. has also led to the development of... | https://en.wikipedia.org/wiki?curid=4502 |
Biotechnology (Chakrabarty's work did not involve gene manipulation but rather the transfer of entire organelles between strains of the "Pseudomonas" bacterium. The MOSFET (metal-oxide-semiconductor field-effect transistor) was invented by Mohamed M. Atalla and Dawon Kahng in 1959. Two years later, Leland C. Clark and ... | https://en.wikipedia.org/wiki?curid=4502 |
Biotechnology A factor influencing the biotechnology sector's success is improved intellectual property rights legislation—and enforcement—worldwide, as well as strengthened demand for medical and pharmaceutical products to cope with an ageing, and ailing, U.S. population. Rising demand for biofuels is expected to be g... | https://en.wikipedia.org/wiki?curid=4502 |
Biotechnology A series of derived terms have been coined to identify several branches of biotechnology, for example: In medicine, modern biotechnology has many applications in areas such as pharmaceutical drug discoveries and production, pharmacogenomics, and genetic testing (or genetic screening). Pharmacogenomics (a ... | https://en.wikipedia.org/wiki?curid=4502 |
Biotechnology Insulin, widely used for the treatment of diabetes, was previously extracted from the pancreas of abattoir animals (cattle or pigs). The genetically engineered bacteria are able to produce large quantities of synthetic human insulin at relatively low cost. has also enabled emerging therapeutics like gene ... | https://en.wikipedia.org/wiki?curid=4502 |
Biotechnology Since genetic testing may open up ethical or psychological problems, genetic testing is often accompanied by genetic counseling. Genetically modified crops ("GM crops", or "biotech crops") are plants used in agriculture, the DNA of which has been modified with genetic engineering techniques. In most cases... | https://en.wikipedia.org/wiki?curid=4502 |
Biotechnology Examples in non-food crops include production of pharmaceutical agents, biofuels, and other industrially useful goods, as well as for bioremediation. Farmers have widely adopted GM technology. Between 1996 and 2011, the total surface area of land cultivated with GM crops had increased by a factor of 94, f... | https://en.wikipedia.org/wiki?curid=4502 |
Biotechnology GM livestock have also been experimentally developed; in November 2013 none were available on the market, but in 2015 the FDA approved the first GM salmon for commercial production and consumption. There is a scientific consensus that currently available food derived from GM crops poses no greater risk to... | https://en.wikipedia.org/wiki?curid=4502 |
Biotechnology In the current decades, significant progress has been done in creating genetically modified organisms (GMOs) that enhance the diversity of applications and economical viability of industrial biotechnology. By using renewable raw materials to produce a variety of chemicals and fuels, industrial biotechnolo... | https://en.wikipedia.org/wiki?curid=4502 |
Biotechnology There are differences in the regulation of GMOs between countries, with some of the most marked differences occurring between the US and Europe. Regulation varies in a given country depending on the intended use of the products of the genetic engineering. For example, a crop not intended for food use is g... | https://en.wikipedia.org/wiki?curid=4502 |
Chemistry is the scientific discipline involved with elements and compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances. In the scope of its subject, chemistry occupies an intermediate position between phy... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry It is often seen as linked to the quest to turn lead or another common starting material into gold, though in ancient times, the study encompassed many of the questions of modern chemistry being defined as the study of the composition of waters, movement, growth, embodying, disembodying, drawing the spirits f... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry Such behaviors are studied in a chemistry laboratory. The chemistry laboratory stereotypically uses various forms of laboratory glassware. However glassware is not central to chemistry, and a great deal of experimental (as well as applied/industrial) chemistry is done without it. A chemical reaction is a tran... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry Several concepts are essential for the study of chemistry; some of them are: In chemistry, matter is defined as anything that has rest mass and volume (it takes up space) and is made up of particles. The particles that make up matter have rest mass as well – not all particles have rest mass, such as the photo... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry The mass number is the sum of the number of protons and neutrons in a nucleus. Although all the nuclei of all atoms belonging to one element will have the same atomic number, they may not necessarily have the same mass number; atoms of an element which have different mass numbers are known as isotopes. For ex... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry A "molecule" is the smallest indivisible portion of a pure chemical substance that has its unique set of chemical properties, that is, its potential to undergo a certain set of chemical reactions with other substances. However, this definition only works well for substances that are composed of molecules, whi... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry The "inert" or noble gas elements (helium, neon, argon, krypton, xenon and radon) are composed of lone atoms as their smallest discrete unit, but the other isolated chemical elements consist of either molecules or networks of atoms bonded to each other in some way. Identifiable molecules compose familiar subs... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry A chemical substance is a kind of matter with a definite composition and set of properties. A collection of substances is called a mixture. Examples of mixtures are air and alloys. The mole is a unit of measurement that denotes an amount of substance (also called chemical amount). The mole is defined as the n... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry Sometimes the distinction between phases can be continuous instead of having a discrete boundary' in this case the matter is considered to be in a supercritical state. When three states meet based on the conditions, it is known as a triple point and since this is invariant, it is a convenient way to define a ... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry More than simple attraction and repulsion, the energies and distributions characterize the availability of an electron to bond to another atom. A chemical bond can be a covalent bond, an ionic bond, a hydrogen bond or just because of Van der Waals force. Each of these kinds of bonds is ascribed to some potent... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry Atoms will share valence electrons in such a way as to create a noble gas electron configuration (eight electrons in their outermost shell) for each atom. Atoms that tend to combine in such a way that they each have eight electrons in their valence shell are said to follow the octet rule. However, some elemen... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry A reaction is said to be exergonic if the final state is lower on the energy scale than the initial state; in the case of endergonic reactions the situation is the reverse. A reaction is said to be exothermic if the reaction releases heat to the surroundings; in the case of endothermic reactions, the reaction... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry These are determined by the rules of quantum mechanics, which require quantization of energy of a bound system. The atoms/molecules in a higher energy state are said to be excited. The molecules/atoms of substance in an excited energy state are often much more reactive; that is, more amenable to chemical reac... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry For example, ultraviolet electromagnetic radiation is not transferred with as much efficacy from one substance to another as thermal or electrical energy. The existence of characteristic energy levels for different chemical substances is useful for their identification by the analysis of spectral lines. Diffe... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry Chemical reactions usually involve the making or breaking of chemical bonds. Oxidation, reduction, dissociation, acid-base neutralization and molecular rearrangement are some of the commonly used kinds of chemical reactions. A chemical reaction can be symbolically depicted through a chemical equation. While i... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry An additional caveat is made, in that this definition includes cases where the interconversion of conformers is experimentally observable. Such detectable chemical reactions normally involve sets of molecular entities as indicated by this definition, but it is often conceptually convenient to use the term als... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry According to Brønsted–Lowry acid-base theory, acids are substances that donate a positive hydrogen ion to another substance in a chemical reaction; by extension, a base is the substance which receives that hydrogen ion. A third common theory is Lewis acid-base theory, which is based on the formation of new ch... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry Redox ("red"uction-"ox"idation) reactions include all chemical reactions in which atoms have their oxidation state changed by either gaining electrons (reduction) or losing electrons (oxidation). Substances that have the ability to oxidize other substances are said to be oxidative and are known as oxidizing a... | https://en.wikipedia.org/wiki?curid=5180 |
Chemistry Thus the concept describes the state in which the parameters such as chemical composition remain unchanged over time. Chemical reactions are governed by certain laws, which have become fundamental concepts in chemistry. Some of them are: The history of chemistry spans a period from very old times to the prese... | https://en.wikipedia.org/wiki?curid=5180 |
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