1.
Animal
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Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
2.
Human
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Modern humans are the only extant members of Hominina tribe, a branch of the tribe Hominini belonging to the family of great apes. Several of these hominins used fire, occupied much of Eurasia and they began to exhibit evidence of behavioral modernity around 50,000 years ago. In several waves of migration, anatomically modern humans ventured out of Africa, the spread of humans and their large and increasing population has had a profound impact on large areas of the environment and millions of native species worldwide. Humans are uniquely adept at utilizing systems of communication for self-expression and the exchange of ideas. Humans create complex structures composed of many cooperating and competing groups, from families. Social interactions between humans have established a wide variety of values, social norms, and rituals. These human societies subsequently expanded in size, establishing various forms of government, religion, today the global human population is estimated by the United Nations to be near 7.5 billion. In common usage, the word generally refers to the only extant species of the genus Homo—anatomically and behaviorally modern Homo sapiens. In scientific terms, the meanings of hominid and hominin have changed during the recent decades with advances in the discovery, there is also a distinction between anatomically modern humans and Archaic Homo sapiens, the earliest fossil members of the species. The English adjective human is a Middle English loanword from Old French humain, ultimately from Latin hūmānus, the words use as a noun dates to the 16th century. The native English term man can refer to the species generally, the species binomial Homo sapiens was coined by Carl Linnaeus in his 18th century work Systema Naturae. The generic name Homo is a learned 18th century derivation from Latin homō man, the species-name sapiens means wise or sapient. Note that the Latin word homo refers to humans of either gender, the genus Homo evolved and diverged from other hominins in Africa, after the human clade split from the chimpanzee lineage of the hominids branch of the primates. The closest living relatives of humans are chimpanzees and gorillas, with the sequencing of both the human and chimpanzee genome, current estimates of similarity between human and chimpanzee DNA sequences range between 95% and 99%. The gibbons and orangutans were the first groups to split from the leading to the humans. The splitting date between human and chimpanzee lineages is placed around 4–8 million years ago during the late Miocene epoch, during this split, chromosome 2 was formed from two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. There is little evidence for the divergence of the gorilla, chimpanzee. Each of these species has been argued to be an ancestor of later hominins
3.
Food
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Food is any substance consumed to provide nutritional support for an organism. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, the substance is ingested by an organism and assimilated by the organisms cells to provide energy, maintain life, or stimulate growth. Historically, humans secured food through two methods, hunting and gathering and agriculture, today, the majority of the food energy required by the ever increasing population of the world is supplied by the food industry. They address issues such as sustainability, biological diversity, climate change, nutritional economics, population growth, water supply, most food has its origin in plants. Some food is obtained directly from plants, but even animals that are used as sources are raised by feeding them food derived from plants. Cereal grain is a food that provides more food energy worldwide than any other type of crop. Corn, wheat, and rice – in all of their varieties – account for 87% of all grain production worldwide, most of the grain that is produced worldwide is fed to livestock. Some foods not from animal or plant sources include various edible fungi, fungi and ambient bacteria are used in the preparation of fermented and pickled foods like leavened bread, alcoholic drinks, cheese, pickles, kombucha, and yogurt. Another example is blue-green algae such as Spirulina, inorganic substances such as salt, baking soda and cream of tartar are used to preserve or chemically alter an ingredient. Many plants and plant parts are eaten as food and around 2,000 plant species are cultivated for food, many of these plant species have several distinct cultivars. Seeds of plants are a source of food for animals, including humans, because they contain the nutrients necessary for the plants initial growth, including many healthful fats. In fact, the majority of food consumed by human beings are seed-based foods, edible seeds include cereals, legumes, and nuts. Oilseeds are often pressed to produce rich oils - sunflower, flaxseed, rapeseed, sesame, seeds are typically high in unsaturated fats and, in moderation, are considered a health food, although not all seeds are edible. Large seeds, such as those from a lemon, pose a choking hazard, fruits are the ripened ovaries of plants, including the seeds within. Many plants and animals have coevolved such that the fruits of the former are a food source to the latter. Fruits, therefore, make up a significant part of the diets of most cultures, some botanical fruits, such as tomatoes, pumpkins, and eggplants, are eaten as vegetables. Vegetables are a type of plant matter that is commonly eaten as food. These include root vegetables, bulbs, leaf vegetables, stem vegetables, animals are used as food either directly or indirectly by the products they produce
4.
Cellular respiration
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Respiration is one of the key ways a cell releases chemical energy to fuel cellular activity. Cellular respiration is considered an exothermic reaction which releases heat. The overall reaction occurs in a series of steps, most of which are redox reactions themselves. Nutrients that are used by animal and plant cells in respiration include sugar, amino acids and fatty acids. The chemical energy stored in ATP can then be used to drive processes requiring energy, including biosynthesis, aerobic respiration requires oxygen in order to create ATP. The potential of NADH and FADH2 is converted to more ATP through a transport chain with oxygen as the terminal electron acceptor. Most of the ATP produced by cellular respiration is made by oxidative phosphorylation. This works by the released in the consumption of pyruvate being used to create a chemiosmotic potential by pumping protons across a membrane. This potential is used to drive ATP synthase and produce ATP from ADP. Biology textbooks often state that 38 ATP molecules can be made per oxidised glucose molecule during cellular respiration, aerobic metabolism is up to 15 times more efficient than anaerobic metabolism. They share the pathway of glycolysis but aerobic metabolism continues with the Krebs cycle. The post-glycolytic reactions take place in the mitochondria in eukaryotic cells, glycolysis is a metabolic pathway that takes place in the cytosol of cells in all living organisms. This pathway can function with or without the presence of oxygen, in humans, aerobic conditions produce pyruvate and anaerobic conditions produce lactate. In aerobic conditions, the process converts one molecule of glucose into two molecules of pyruvate, generating energy in the form of two net molecules of ATP, four molecules of ATP per glucose are actually produced, however, two are consumed as part of the preparatory phase. The initial phosphorylation of glucose is required to increase the reactivity in order for the molecule to be cleaved into two molecules by the enzyme aldolase. During the pay-off phase of glycolysis, four groups are transferred to ADP by substrate-level phosphorylation to make four ATP. Glycogen can be converted into glucose 6-phosphate as well with the help of glycogen phosphorylase, during energy metabolism, glucose 6-phosphate becomes fructose 6-phosphate. An additional ATP is used to phosphorylate fructose 6-phosphate into fructose 1, fructose 1, 6-diphosphate then splits into two phosphorylated molecules with three carbon chains which later degrades into pyruvate
5.
Oxygen
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Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the group on the periodic table and is a highly reactive nonmetal. By mass, oxygen is the third-most abundant element in the universe, after hydrogen, at standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. This is an important part of the atmosphere and diatomic oxygen gas constitutes 20. 8% of the Earths atmosphere, additionally, as oxides the element makes up almost half of the Earths crust. Most of the mass of living organisms is oxygen as a component of water, conversely, oxygen is continuously replenished by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide. Oxygen is too reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form of oxygen, ozone, strongly absorbs ultraviolet UVB radiation, but ozone is a pollutant near the surface where it is a by-product of smog. At low earth orbit altitudes, sufficient atomic oxygen is present to cause corrosion of spacecraft, the name oxygen was coined in 1777 by Antoine Lavoisier, whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion. One of the first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics, Philo of Byzantium. In his work Pneumatica, Philo observed that inverting a vessel over a burning candle, Philo incorrectly surmised that parts of the air in the vessel were converted into the classical element fire and thus were able to escape through pores in the glass. Many centuries later Leonardo da Vinci built on Philos work by observing that a portion of air is consumed during combustion and respiration, Oxygen was discovered by the Polish alchemist Sendivogius, who considered it the philosophers stone. In the late 17th century, Robert Boyle proved that air is necessary for combustion, English chemist John Mayow refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus. From this he surmised that nitroaereus is consumed in both respiration and combustion, Mayow observed that antimony increased in weight when heated, and inferred that the nitroaereus must have combined with it. Accounts of these and other experiments and ideas were published in 1668 in his work Tractatus duo in the tract De respiratione. Robert Hooke, Ole Borch, Mikhail Lomonosov, and Pierre Bayen all produced oxygen in experiments in the 17th and the 18th century but none of them recognized it as a chemical element. This may have been in part due to the prevalence of the philosophy of combustion and corrosion called the phlogiston theory, which was then the favored explanation of those processes. Established in 1667 by the German alchemist J. J. Becher, one part, called phlogiston, was given off when the substance containing it was burned, while the dephlogisticated part was thought to be its true form, or calx. The fact that a substance like wood gains overall weight in burning was hidden by the buoyancy of the combustion products
6.
Anaerobic respiration
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Anaerobic respiration is respiration using electron acceptors other than oxygen. Although oxygen is not used as the electron acceptor, the process still uses a respiratory electron transport chain called physolmere. Kalim In aerobic organisms undergoing respiration, electrons are shuttled to a transport chain. Molecular oxygen is an oxidizing agent and, therefore, is an excellent acceptor. In anaerobes, other less-oxidizing substances such as sulfate, nitrate, sulphur and these terminal electron acceptors have smaller reduction potentials than O2, meaning that less energy is released per oxidized molecule. Anaerobic respiration is, therefore, in general energetically less efficient than aerobic respiration, anaerobic respiration is used mainly by bacteria and archaea that live in environments devoid of oxygen. Many anaerobic organisms are obligate anaerobes meaning that they can respire only using anaerobic compounds, a proton motive force or pmf drives protons down the gradient through the proton channel of ATP synthase. The resulting current drives ATP synthesis from ADP and inorganic phosphate, fermentation, in contrast, does not utilize an electrochemical gradient. Fermentation instead only uses substrate-level phosphorylation to produce ATP, the electron acceptor NAD+ is regenerated from NADH formed in oxidative steps of the fermentation pathway by the reduction of oxidized compounds. These oxidized compounds are formed during the fermentation pathway itself. In yeast, acetaldehyde is reduced to ethanol to regenerate NAD+, the two processes thus generate ATP in very different ways, and the terms should not be treated as synonyms. Anaerobic respiration is a component of the global nitrogen, iron, sulfur, and carbon cycles through the reduction of the oxyanions of nitrogen, sulfur. The biogeochemical cycling of these compounds, which depends upon anaerobic respiration, significantly impacts the carbon cycle, anaerobic respiration occurs in many environments, including freshwater and marine sediments, soil, subsurface aquifers, deep subsurface environments, and biofilms. Even environments, such as soil, that contain oxygen also have micro-environments that lack oxygen due to the slow diffusion characteristics of oxygen gas, another example is methanogenesis, a form of carbonate respiration, that is used to produce methane gas by anaerobic digestion. Biogenic methane is used as an alternative to fossil fuels. On the negative side, uncontrolled methanogenesis in landfill sites releases large volumes of methane into the atmosphere, dissimilatory denitrification is widely used in the removal of nitrate and nitrite from municipal wastewater. An excess of nitrate can lead to eutrophication of waterways into which treated water is released, elevated nitrite levels in drinking water can lead to problems due to its toxicity. Denitrification converts both compounds into harmless nitrogen gas, for example, toxic arsenate or selenate can be reduced to less toxic compounds by various anaerobic bacteria via anaerobic respiration
7.
Metabolism
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Metabolism is the set of life-sustaining chemical transformations within the cells of living organisms. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, usually, breaking down releases energy and building up consumes energy. The chemical reactions of metabolism are organized into metabolic pathways, in one chemical is transformed through a series of steps into another chemical. Enzymes act as catalysts that allow the reactions to proceed more rapidly, enzymes also allow the regulation of metabolic pathways in response to changes in the cells environment or to signals from other cells. The metabolic system of a particular organism determines which substances it will find nutritious, for example, some prokaryotes use hydrogen sulfide as a nutrient, yet this gas is poisonous to animals. The speed of metabolism, the rate, influences how much food an organism will require. A striking feature of metabolism is the similarity of the metabolic pathways. These striking similarities in metabolic pathways are likely due to their appearance in evolutionary history. Most of the structures that make up animals, plants and microbes are made from three classes of molecule, amino acids, carbohydrates and lipids. These biochemicals can be joined together to make such as DNA and proteins. Proteins are made of amino acids arranged in a linear chain joined together by peptide bonds, many proteins are enzymes that catalyze the chemical reactions in metabolism. Other proteins have structural or mechanical functions, such as those that form the cytoskeleton, Proteins are also important in cell signaling, immune responses, cell adhesion, active transport across membranes, and the cell cycle. Lipids are the most diverse group of biochemicals and their main structural uses are as part of biological membranes both internal and external, such as the cell membrane, or as a source of energy. Lipids are usually defined as hydrophobic or amphipathic biological molecules but will dissolve in organic solvents such as benzene or chloroform, the fats are a large group of compounds that contain fatty acids and glycerol, a glycerol molecule attached to three fatty acid esters is called a triacylglyceride. Several variations on this structure exist, including alternate backbones such as sphingosine in the sphingolipids. Steroids such as cholesterol are another class of lipids. Carbohydrates are aldehydes or ketones, with hydroxyl groups attached. Carbohydrates are the most abundant biological molecules, and fill numerous roles, such as the storage and transport of energy, the basic carbohydrate units are called monosaccharides and include galactose, fructose, and most importantly glucose
8.
Carbohydrate
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A carbohydrate is a biological molecule consisting of carbon, hydrogen and oxygen atoms, usually with a hydrogen–oxygen atom ratio of 2,1, in other words, with the empirical formula Cmn. This formula holds true for monosaccharides, some exceptions exist, for example, deoxyribose, a sugar component of DNA, has the empirical formula C5H10O4. Carbohydrates are technically hydrates of carbon, structurally it is accurate to view them as polyhydroxy aldehydes and ketones. The term is most common in biochemistry, where it is a synonym of saccharide, a group that includes sugars, starch, the saccharides are divided into four chemical groups, monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Monosaccharides and disaccharides, the smallest carbohydrates, are referred to as sugars. The word saccharide comes from the Greek word σάκχαρον, meaning sugar, while the scientific nomenclature of carbohydrates is complex, the names of the monosaccharides and disaccharides very often end in the suffix -ose. For example, grape sugar is the glucose, cane sugar is the disaccharide sucrose. Carbohydrates perform numerous roles in living organisms, polysaccharides serve for the storage of energy and as structural components. The 5-carbon monosaccharide ribose is an important component of coenzymes and the backbone of the genetic molecule known as RNA, the related deoxyribose is a component of DNA. Saccharides and their derivatives include many other important biomolecules that play key roles in the system, fertilization, preventing pathogenesis, blood clotting. In food science and in informal contexts, the term carbohydrate often means any food that is particularly rich in the complex carbohydrate starch or simple carbohydrates. Often in lists of information, such as the USDA National Nutrient Database, the term carbohydrate is used for everything other than water, protein, fat, ash. This will include chemical compounds such as acetic or lactic acid, carbohydrates are found in wide variety of foods. The important sources are cereals, potatoes, sugarcane, fruits, table sugar, bread, milk, starch and sugar are the important carbohydrates in our diet. Starch is abundant in potatoes, maize, rice and other cereals, sugar appears in our diet mainly as sucrose which is added to drinks and many prepared foods such as jam, biscuits and cakes. Glucose and fructose are found naturally in fruits and some vegetables. Glycogen is carbohydrate found in the liver and muscles, cellulose in the cell wall of all plant tissue is a carbohydrate. It is important in our diet as fibre which helps to maintain a healthy digestive system, formerly the name carbohydrate was used in chemistry for any compound with the formula Cm n
9.
Fat
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Fat is one of the three main macronutrients, along with carbohydrate and protein. Fats, also known as triglycerides, are esters of three fatty acid chains and the alcohol glycerol, the terms oil, fat, and lipid are often confused. Oil normally refers to a fat with short or unsaturated fatty acid chains that is liquid at room temperature, lipid is the general term, as a lipid is not necessarily a triglyceride. Fats, like lipids, are generally hydrophobic, and are soluble in organic solvents. Fat is an important foodstuff for many forms of life, and they are a necessary part of the diet of most heterotrophs. Some fatty acids that are set free by the digestion of fats are called essential because they cannot be synthesized in the body from simpler constituents, there are two essential fatty acids in human nutrition, alpha-linolenic acid and linoleic acid. Other lipids needed by the body can be synthesized from these, fats and other lipids are broken down in the body by enzymes called lipases produced in the pancreas. Fats and oils are categorized according to the number and bonding of the atoms in the aliphatic chain. Fats that are saturated fats have no double bonds between the carbons in the chain, unsaturated fats have one or more double bonded carbons in the chain. The nomenclature is based on the end of the chain. This end is called the end or the n-end. Thus alpha-linolenic acid is called an omega-3 fatty acid because the 3rd carbon from that end is the first double bonded carbon in the counting from that end. Some oils and fats have double bonds and are therefore called polyunsaturated fats. Unsaturated fats can be divided into cis fats, which are the most common in nature, and trans fats. Unsaturated fats can be altered by reaction with hydrogen effected by a catalyst and this action, called hydrogenation, tends to break all the double bonds and makes a fully saturated fat. However, trans fats are generated during hydrogenation as contaminants created by a side reaction on the catalyst during partial hydrogenation. Saturated fats can stack themselves in a closely packed arrangement, so they can easily and are typically solid at room temperature. For example, animal fats tallow and lard are high in saturated fatty acid content and are solids, olive and linseed oils on the other hand are unsaturated and liquid
10.
Protein (nutrient)
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Proteins are essential nutrients for the human body. They are one of the blocks of body tissue. As a fuel, proteins provide as much energy density as carbohydrates,4 kcal per gram, in contrast, the most important aspect and defining characteristic of protein from a nutritional standpoint is its amino acid composition. Proteins are polymer chains made of amino acids linked together by peptide bonds, during human digestion, proteins are broken down in the stomach to smaller polypeptide chains via hydrochloric acid and protease actions. This is crucial for the synthesis of the amino acids that cannot be biosynthesized by the body. There are nine amino acids which humans must obtain from their diet in order to prevent protein-energy malnutrition. They are phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, there are five dispensable amino acids which humans are able to synthesize in the body. These five are alanine, aspartic acid, asparagine, glutamic acid and these six are arginine, cysteine, glycine, glutamine, proline and tyrosine. Humans need the essential amino acids in certain ratios, some protein sources contain amino acids in a more or less complete sense. This has given rise to various ranking systems for protein sources, Dietary sources of protein include both animals and plants, meats, dairy products, fish and eggs as well as grains, legumes and nuts. Vegetarians and vegans can get enough essential amino acids by eating a variety of plant proteins and it is commonly believed that athletes should consume a higher-than-normal protein intake to maintain optimal physical performance. Protein is a nutrient needed by the body for growth. Aside from water, proteins are the most abundant kind of molecules in the body, Protein can be found in all cells of the body and is the major structural component of all cells in the body, especially muscle. This also includes body organs, hair and skin, proteins are also used in membranes, such as glycoproteins. When broken down into amino acids, they are used as precursors to acid, co-enzymes, hormones, immune response, cellular repair. Additionally, protein is needed to form blood cells, proteins are believed to increase performance in terms of athletics. Amino acids, the blocks of proteins, are used for building muscle tissue. Protein is only used as fuel when carbohydrates are low
11.
Water
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Water is a transparent and nearly colorless chemical substance that is the main constituent of Earths streams, lakes, and oceans, and the fluids of most living organisms. Its chemical formula is H2O, meaning that its molecule contains one oxygen, Water strictly refers to the liquid state of that substance, that prevails at standard ambient temperature and pressure, but it often refers also to its solid state or its gaseous state. It also occurs in nature as snow, glaciers, ice packs and icebergs, clouds, fog, dew, aquifers, Water covers 71% of the Earths surface. It is vital for all forms of life. Only 2. 5% of this water is freshwater, and 98. 8% of that water is in ice and groundwater. Less than 0. 3% of all freshwater is in rivers, lakes, and the atmosphere, a greater quantity of water is found in the earths interior. Water on Earth moves continually through the cycle of evaporation and transpiration, condensation, precipitation. Evaporation and transpiration contribute to the precipitation over land, large amounts of water are also chemically combined or adsorbed in hydrated minerals. Safe drinking water is essential to humans and other even though it provides no calories or organic nutrients. There is a correlation between access to safe water and gross domestic product per capita. However, some observers have estimated that by 2025 more than half of the population will be facing water-based vulnerability. A report, issued in November 2009, suggests that by 2030, in developing regions of the world. Water plays an important role in the world economy, approximately 70% of the freshwater used by humans goes to agriculture. Fishing in salt and fresh water bodies is a source of food for many parts of the world. Much of long-distance trade of commodities and manufactured products is transported by boats through seas, rivers, lakes, large quantities of water, ice, and steam are used for cooling and heating, in industry and homes. Water is an excellent solvent for a variety of chemical substances, as such it is widely used in industrial processes. Water is also central to many sports and other forms of entertainment, such as swimming, pleasure boating, boat racing, surfing, sport fishing, Water is a liquid at the temperatures and pressures that are most adequate for life. Specifically, at atmospheric pressure of 1 bar, water is a liquid between the temperatures of 273.15 K and 373.15 K
12.
Vitamin
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A vitamin is an organic compound and a vital nutrient that an organism requires in limited amounts. For example, ascorbic acid is a vitamin for humans, supplementation is important for the treatment of certain health problems, but there is little evidence of nutritional benefit when used by otherwise healthy people. Thirteen vitamins are universally recognized at present, Vitamins are classified by their biological and chemical activity, not their structure. Thus, each vitamin refers to a number of compounds that all show the biological activity associated with a particular vitamin. Such a set of chemicals is grouped under an alphabetized vitamin generic descriptor title, such as vitamin A, which includes the compounds retinal, retinol, and four known carotenoids. Vitamers by definition are convertible to the form of the vitamin in the body. Some, such as vitamin D, have hormone-like functions as regulators of mineral metabolism, or regulators of cell and tissue growth and differentiation. The largest number of vitamins, the B complex vitamins, function as cofactors or the precursors for them. In this role, vitamins may be bound to enzymes as part of prosthetic groups, For example. They may also be less tightly bound to enzyme catalysts as coenzymes, for example, folic acid may carry methyl, formyl, and methylene groups in the cell. Although these roles in assisting enzyme-substrate reactions are vitamins best-known function, study of structural activity, function and their role in maintaining health is called vitaminology. Each vitamin is typically used in reactions, and therefore most have multiple functions. Vitamins are essential for the growth and development of a multicellular organism. Using the genetic blueprint inherited from its parents, a fetus begins to develop from the nutrients it absorbs and it requires certain vitamins and minerals to be present at certain times. These nutrients facilitate the chemical reactions that produce among other things, skin, bone, if there is serious deficiency in one or more of these nutrients, a child may develop a deficiency disease. Even minor deficiencies may cause permanent damage, for the most part, vitamins are obtained with food, but a few are obtained by other means. Humans can produce some vitamins from precursors they consume, examples include vitamin A, produced from beta carotene, and niacin, from the amino acid tryptophan. In those who are healthy, there is little evidence that supplements have any benefits with respect to cancer or heart disease
13.
Dietary mineral
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In the context of nutrition, a mineral is a chemical element required as an essential nutrient by organisms to perform functions necessary for life. Minerals originate in the earth and cannot be made by living organisms, most of the minerals in a human diet come from eating plants and animals or from drinking water. As a group, minerals are one of the four groups of essential nutrients, the others of which are vitamins, essential fatty acids, the five major minerals in the human body are calcium, phosphorus, potassium, sodium, and magnesium. All of the elements in a human body are called trace elements. The trace elements that have a specific function in the human body are iron, cobalt, copper, zinc, manganese, molybdenum, iodine. Most chemical elements that are ingested by organisms are in the form of simple compounds, plants absorb dissolved elements in soils, which are subsequently ingested by the herbivores that eat them, and the elements move up the food chain. Larger organisms may also consume soil or use mineral resources, such as salt licks, one element, cobalt, is available for use by animals only after having been processed into complex molecules by bacteria. Minerals are used by animals and microorganisms for the process of mineralizing structures, called biomineralization, used to construct bones, seashells, eggshells, exoskeletons and mollusc shells. At least twenty chemical elements are known to be required to support human biochemical processes by serving structural and functional roles as well as electrolytes, however, as many as twenty-nine elements in total are suggested to be used by mammals, as inferred by biochemical and uptake studies. Phosphorus makes up about 1% of a body weight. The last four major minerals make up only about 0. 85% of the weight of the body, together these eleven chemical elements make up 99. 85% of the body. Minerals are present in a human beings blood at certain mass. The figure below presents the concentrations of each of the elements discussed in this article. Depending on the concentrations, some are in part of the picture. The figure includes the values of other constituents of blood such as hormones. In the figure, minerals are color highlighted in purple, dietitians may recommend that minerals are best supplied by ingesting specific foods rich with the chemical element of interest. The elements may be present in the food or added to the food. The dietary focus on chemical elements derives from an interest in supporting the biochemical reactions of metabolism with the elemental components
14.
Organic acid
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An organic acid is an organic compound with acidic properties. The most common organic acids are the carboxylic acids, whose acidity is associated with their carboxyl group –COOH, sulfonic acids, containing the group –SO2OH, are relatively stronger acids. Alcohols, with –OH, can act as acids but they are very weak. The relative stability of the base of the acid determines its acidity. Other groups can also confer acidity, usually weakly, the thiol group –SH, the group. In biological systems, organic compounds containing these groups are referred to as organic acids. In general, organic acids are acids and do not dissociate completely in water. Lower molecular mass organic acids such as formic and lactic acids are miscible in water, on the other hand, most organic acids are very soluble in organic solvents. P-Toluenesulfonic acid is a strong acid used in organic chemistry often because it is able to dissolve in the organic reaction solvent. Exceptions to these solubility characteristics exist in the presence of other substituents that affect the polarity of the compound. The pKa a logarithmic measure of the dissociation constant, categorizes the strength of an acid, the lower or more negative the number. It should not be confused with pH, the measure of actual hydrogen ion concentration. Phenol C6H5OH The 19th century name carbolic acid came from the original German name karbolsäure and it is a weak, non-carboxylic acid, but is corrosive and causes chemical burns on the skin due to a protein-degenerating effect. Uric acid C5H4N4O3 Uric acid is a purine derivative which is a diprotic acid but not a carboxylic one. Taurine C2H7NO3S One of the few natural sulfonic acids, discovered in bile, p-Toluenesulfonic acid CH3C6H4SO3H A strong acid that, unlike some strong mineral acids, is non-oxidizing. Trifluoromethanesulfonic acid CF3SO3H One of the strongest acids in existence, organic or inorganic, about a thousand times stronger than sulfuric acid, first synthesized in 1954, it also resists oxidation/reduction reactions and does not sulfonate substrates like sulfuric or chlorosulfonic acid. Aminomethylphosphonic acid A strong phosphonic acid Simple organic acids like formic or acetic acids are used for oil and these organic acids are much less reactive with metals than are strong mineral acids like hydrochloric acid or mixtures of HCl and hydrofluoric acid. For this reason, organic acids are used at temperatures or when long contact times between acid and pipe are needed
15.
Polyol
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A polyol is an alcohol containing multiple hydroxyl groups. In two different technological disciplines the term polyol has a meaning, food science and polymer chemistry. They are also added to chewing gum because they are not broken down by bacteria in the mouth or metabolized to acids, maltitol, sorbitol, xylitol, erythritol, and isomalt are some of the more common types. Sugar alcohols may be formed under reducing conditions from their analogue sugars. In polymer chemistry, polyols are compounds with multiple functional groups available for organic reactions. A molecule with two groups is a diol, one with three is a triol, one with four is a tetrol and so on. Monomeric polyols such as glycerin, pentaerythritol, ethylene glycol and sucrose often serve as the point for polymeric polyols. These materials are referred to as the initiators and reacted with propylene oxide or ethylene oxide to produce polymeric polyols. However, they should not be confused with radical initiators used to promote other polymerization reactions. The functional group used as the point for a polymeric polyol need not be a hydroxyl group. A primary amino group often functions as the point for two polymeric chains, especially in the case of polyether polyols. Polymeric polyols are used to produce other polymers. They are reacted with isocyanates to make polyurethanes used to make mattresses, foam insulation for appliances, home and automotive seats, elastomeric shoe soles, fibers, polymeric polyols are usually polyethers or polyesters. Common polyether diols are polyethylene glycol, polypropylene glycol, and poly glycol, the examples shown below are fairly low molecular weight triols based on glycerin being reacted with propylene oxide, ethylene oxide or a combination of the two. In reality, the chains would not be of length in any one molecule. Polyether polyols account for about 90% of the polymeric polyols used industrially, another class of polymeric polyols is the polyesters. Polyesters are formed by condensation or step-growth polymerization of diols and dicarboxylic acids, alternatively, the hydroxyl group and the carboxylic acid may be within the same molecule, as in the case of caprolactone. The example below is a structure that could be obtained by reacting pentaerythritol with gamma-butyrolactone
16.
Ethanol
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Ethanol, also called alcohol, ethyl alcohol, and drinking alcohol, is the principal type of alcohol found in alcoholic beverages. It is a volatile, flammable, colorless liquid with a characteristic odor. Its chemical formula is C 2H 6O, which can be written also as CH 3-CH 2-OH or C 2H 5-OH, ethanol is mostly produced by the fermentation of sugars by yeasts, or by petrochemical processes. It is a psychoactive drug, causing a characteristic intoxication. It is widely used as a solvent, as fuel, and as a feedstock for synthesis of other chemicals, the eth- prefix and the qualifier ethyl in ethyl alcohol originally come from the name ethyl assigned in 1834 to the group C 2H 5- by Justus Liebig. He coined the word from the German name Aether of the compound C 2H 5-O-C 2H5, according to the Oxford English Dictionary, Ethyl is a contraction of the Ancient Greek αἰθήρ and the Greek word ύλη. The name ethanol was coined as a result of a resolution that was adopted at the International Conference on Chemical Nomenclature that was held in April 1892 in Geneva, Switzerland. The term alcohol now refers to a class of substances in chemistry nomenclature. The Oxford English Dictionary claims that it is a loan from Arabic al-kuḥl, a powdered ore of antimony used since aniquity as a cosmetic. The use of alcohol for ethanol is modern, first recorded 1753, the systematic use in chemistry dates to 1850. Ethanol is used in medical wipes and most common antibacterial hand sanitizer gels as an antiseptic, ethanol kills organisms by denaturing their proteins and dissolving their lipids and is effective against most bacteria and fungi, and many viruses. However, ethanol is ineffective against bacterial spores, ethanol may be administered as an antidote to methanol and ethylene glycol poisoning. Ethanol, often in high concentrations, is used to dissolve many water-insoluble medications, as a central nervous system depressant, ethanol is one of the most commonly consumed psychoactive drugs. The amount of ethanol in the body is typically quantified by blood alcohol content, small doses of ethanol, in general, produce euphoria and relaxation, people experiencing these symptoms tend to become talkative and less inhibited, and may exhibit poor judgment. Ethanol is commonly consumed as a drug, especially while socializing. The largest single use of ethanol is as a fuel and fuel additive. Brazil in particular relies heavily upon the use of ethanol as an engine fuel, gasoline sold in Brazil contains at least 25% anhydrous ethanol. Hydrous ethanol can be used as fuel in more than 90% of new gasoline fueled cars sold in the country, Brazilian ethanol is produced from sugar cane and noted for high carbon sequestration
17.
Diet (nutrition)
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In nutrition, diet is the sum of food consumed by a person or other organism. The word diet often implies the use of intake of nutrition for health or weight-management reasons. Although humans are omnivores, each culture and each person holds some food preferences or some food taboos and this may be due to personal tastes or ethical reasons. Individual dietary choices may be more or less healthy, complete nutrition requires ingestion and absorption of vitamins, minerals, and food energy in the form of carbohydrates, proteins, and fats. Dietary habits and choices play a significant role in the quality of life, health, some cultures and religions have restrictions concerning what foods are acceptable in their diet. For example, only Kosher foods are permitted by Judaism, although Buddhists are generally vegetarians, the practice varies and meat-eating may be permitted depending on the sects. In Hinduism, vegetarianism is the ideal, jains are strictly vegetarian and consumption of roots is not permitted. Raw foodism is another contemporary trend and these diets may require tuning or supplementation such as vitamins to meet ordinary nutritional needs. A particular diet may be chosen to seek weight loss or weight gain, changing a subjects dietary intake, or going on a diet, can change the energy balance and increase or decrease the amount of fat stored by the body. Some foods are recommended, or even altered, for conformity to the requirements of a particular diet. These diets are recommended in conjunction with exercise. Specific weight loss programs can be harmful to health, while others may be beneficial, the terms healthy diet and diet for weight management are often related, as the two promote healthy weight management. Having a healthy diet is a way to prevent health problems, and will provide the body with the balance of vitamins, minerals. An eating disorder is a disorder that interferes with normal food consumption. It is defined by abnormal eating habits that may involve either insufficient or excessive diet, a healthy diet may improve or maintain optimal health. In developed countries, affluence enables unconstrained caloric intake and possibly inappropriate food choices, health agencies recommend that people maintain a normal weight by limiting consumption of energy-dense foods and sugary drinks, eat plant-based food, limit red and processed meat, and limit alcohol. Diet food Dieting Dessert crop Nutrition psychology The dictionary definition of diet at Wiktionary
18.
Cholesterol
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Cholesterol, from the Ancient Greek chole- and stereos followed by the chemical suffix -ol for an alcohol, is an organic molecule. Cholesterol enables animal cells to dispense with a wall, thereby allowing animal cells to change shape rapidly. In addition to its importance for cell structure, cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acid. Cholesterol is the principal sterol synthesized by all animals, in vertebrates, hepatic cells typically produce the greatest amounts. It is absent among prokaryotes, although there are exceptions, such as Mycoplasma. François Poulletier de la Salle first identified cholesterol in solid form in gallstones in 1769, however, it was not until 1815 that chemist Michel Eugène Chevreul named the compound cholesterine. Furthermore, it can be absorbed directly from animal-based foods, a human male weighing 68 kg normally synthesizes about 1 gram per day, and his body contains about 35 g, mostly contained within the cell membranes. Typical daily cholesterol dietary intake for a man in the United States is 307 mg, most ingested cholesterol is esterified, and esterified cholesterol is poorly absorbed. The body also compensates for any absorption of cholesterol by reducing cholesterol synthesis. For these reasons, cholesterol in food, seven to ten hours after ingestion, has little and it is also important to recognize, however, that the concentrations measured in the samples of blood plasma vary with the measurement methods used. Cholesterol is recycled in the body, the liver excretes it in a non-esterified form into the digestive tract. Typically, about 50% of the excreted cholesterol is reabsorbed by the small intestine back into the bloodstream, plants make cholesterol in very small amounts. Plants manufacture phytosterols, which can compete with cholesterol for reabsorption in the intestinal tract, when intestinal lining cells absorb phytosterols, in place of cholesterol, they usually excrete the phytosterol molecules back into the GI tract, an important protective mechanism. Cholesterol, given that it composes about 30% of all cell membranes, is required to build. The membrane remains stable and durable without being rigid, allowing cells to change shape. In this structural role, cholesterol also reduces the permeability of the membrane to neutral solutes, hydrogen ions. Within the cell membrane, cholesterol also functions in intracellular transport, cell signaling, cholesterol is essential for the structure and function of invaginated caveolae and clathrin-coated pits, including caveola-dependent and clathrin-dependent endocytosis. The role of cholesterol in endocytosis of these types can be investigated by using methyl beta cyclodextrin to remove cholesterol from the plasma membrane, in multiple layers, cholesterol and phospholipids, both electrical insulators, can facilitate speed of transmission of electrical impulses along nerve tissue
19.
Ruminant
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Ruminants are mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. The process typically requires the fermented ingesta to be regurgitated and chewed again, the process of rechewing the cud to further break down plant matter and stimulate digestion is called rumination. The word ruminant comes from the Latin ruminare, which means to chew over again, the roughly 150 species of ruminants includes both domestic and wild species. Ruminating mammals include cattle, goats, sheep, giraffes, yaks, deer, antelope and it has also been suggested that notoungulates also relied on rumination, as opposed to other antlantogenates that relied on the more typical hindgut fermentation, though this is not entirely certain. Taxonomically, the suborder Ruminantia is a lineage of herbivorous artiodactyls that includes the most advanced, the term ruminant is not synonymous with Ruminantia. The suborder Ruminantia includes many ruminant species, but does not include tylopods, the primary difference between a ruminant and nonruminant is that ruminants have a four-compartment stomach. The four parts are the rumen, reticulum, omasum, in the first two chambers, the rumen and the reticulum, the food is mixed with saliva and separates into layers of solid and liquid material. Solids clump together to form the cud or bolus, the cud is then regurgitated and chewed to completely mix it with saliva and to break down the particle size. Fiber, especially cellulose and hemicellulose, is broken down in these chambers by microbes into the three volatile fatty acids, acetic acid, propionic acid, and butyric acid. Protein and nonstructural carbohydrate are also fermented, though the rumen and reticulum have different names, they represent the same functional space as digesta can move back and forth between them. Together, these chambers are called the reticulorumen, after this, the digesta is moved to the true stomach, the abomasum. The abomasum is the equivalent of the monogastric stomach. Digesta is finally moved into the intestine, where the digestion and absorption of nutrients occurs. Microbes produced in the reticulorumen are also digested in the small intestine, fermentation continues in the large intestine in the same way as in the reticulorumen. Only small amounts of glucose are absorbed from dietary carbohydrates, most dietary carbohydrates are fermented into VFAs in the rumen. The VFA propionate is used for around 70% of the glucose and glycogen produced, also, some mammals are pseudoruminants, which have a three-compartment stomach instead of four like ruminants. Pseudoruminants, like traditional ruminants, are foregut fermentors and most ruminate or chew cud, however, their anatomy and method of digestion differs significantly from that of a four-chambered ruminant. Monogastric herbivores, such as rhinoceroses, horses, and rabbits, are not ruminants and these hindgut fermenters digest cellulose in an enlarged cecum through the reingestion of the cecotrope
20.
Cellulose
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Cellulose is an organic compound with the formula n, a polysaccharide consisting of a linear chain of several hundred to many thousands of β linked D-glucose units. Cellulose is an important structural component of the cell wall of green plants, many forms of algae. Some species of bacteria secrete it to form biofilms, Cellulose is the most abundant organic polymer on Earth. The cellulose content of cotton fiber is 90%, that of wood is 40–50%, Cellulose is mainly used to produce paperboard and paper. Smaller quantities are converted into a variety of derivative products such as cellophane. Conversion of cellulose from energy crops into biofuels such as ethanol is under investigation as an alternative fuel source. Cellulose for industrial use is mainly obtained from wood pulp and cotton, some animals, particularly ruminants and termites, can digest cellulose with the help of symbiotic micro-organisms that live in their guts, such as Trichonympha. In humans, cellulose acts as a bulking agent for feces and is often referred to as a dietary fiber. Cellulose was discovered in 1838 by the French chemist Anselme Payen, Cellulose was used to produce the first successful thermoplastic polymer, celluloid, by Hyatt Manufacturing Company in 1870. Production of rayon from cellulose began in the 1890s and cellophane was invented in 1912, hermann Staudinger determined the polymer structure of cellulose in 1920. The compound was first chemically synthesized in 1992, by Kobayashi, Cellulose has no taste, is odorless, is hydrophilic with the contact angle of 20–30 degrees, is insoluble in water and most organic solvents, is chiral and is biodegradable. It was shown to melt at 467 °C in 2016 and it can be broken down chemically into its glucose units by treating it with concentrated mineral acids at high temperature. Cellulose is derived from D-glucose units, which condense through β-glycosidic bonds and this linkage motif contrasts with that for α-glycosidic bonds present in starch and glycogen. This confers tensile strength in cell walls, where cellulose microfibrils are meshed into a polysaccharide matrix, compared to starch, cellulose is also much more crystalline. Whereas starch undergoes a crystalline to amorphous transition when heated beyond 60–70 °C in water, cellulose requires a temperature of 320 °C, several different crystalline structures of cellulose are known, corresponding to the location of hydrogen bonds between and within strands. Natural cellulose is cellulose I, with structures Iα and Iβ, Cellulose produced by bacteria and algae is enriched in Iα while cellulose of higher plants consists mainly of Iβ. Cellulose in regenerated cellulose fibers is cellulose II, the conversion of cellulose I to cellulose II is irreversible, suggesting that cellulose I is metastable and cellulose II is stable. With various chemical treatments it is possible to produce the structures cellulose III, many properties of cellulose depend on its chain length or degree of polymerization, the number of glucose units that make up one polymer molecule
21.
Bacteria
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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
22.
Rumen
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The rumen, also known as a paunch, forms the larger part of the reticulorumen, which is the first chamber in the alimentary canal of ruminant animals. It serves as the site for microbial fermentation of ingested feed. The smaller part of the reticulorumen is the reticulum, which is continuous with the rumen. The rumen is composed of several muscular sacs, the sac, ventral sac, ventral blindsac. The lining of the wall is covered in small fingerlike projections called papillae. The reticulum is lined with ridges that form a honeycomb pattern. The ridges are approximately 0.1 -0.2 mm wide and are raised 5 mm above the reticulum wall, the hexagons in the reticulum are approximately 2–5 cm wide in cattle. These features increase the area of the reticulorumen wall, facilitating the absorption of volatile fatty acids. Despite the differences in the texture of the lining of the two parts of the reticulorumen, it represents one functional space. Digested food in the rumen is not uniform, but rather stratified into gas, liquid, and particles of different sizes, densities, and other physical characteristics. Additionally, digesta does not merely enter and exit the rumen without event, but it is subject to extensive mixing, after being swallowed, food travels down the oesophagus and is deposited in the dorsal part of the reticulum. Contractions of the reticulorumen propel and mix the recently ingested feed into the ruminal mat, the mat is a thick mass of digesta, consisting of partially degraded, long, fibrous material. Most material in the mat has been ingested, and as such, has considerable fermentable substrate remaining. Microbial fermentation proceeds rapidly in the mat, releasing many gases, some of these gases are trapped in the mat, causing the mat to be buoyant. As fermentation proceeds, fermentable substrate is exhausted, gas production decreases, digesta in the mat hence goes through a phase of increasing buoyancy followed by decreasing buoyancy. Simultaneously, the size of digesta particles–relatively large when ingested–is reduced by microbial fermentation and, later, incomplete digestion of plant material here will result in the formation of a type of bezoar called Phythobezoars. Once in the sac, digesta continues to ferment at decreased rates, further losing buoyancy. It is soon swept into the ventral reticulum by ruminal contractions, in the ventral reticulum, less dense, larger digesta particles may be propelled up into the oesophagus and mouth during contractions of the reticulum
23.
International System of Units
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The International System of Units is the modern form of the metric system, and is the most widely used system of measurement. It comprises a coherent system of units of measurement built on seven base units, the system also establishes a set of twenty prefixes to the unit names and unit symbols that may be used when specifying multiples and fractions of the units. The system was published in 1960 as the result of an initiative began in 1948. It is based on the system of units rather than any variant of the centimetre-gram-second system. The motivation for the development of the SI was the diversity of units that had sprung up within the CGS systems, the International System of Units has been adopted by most developed countries, however, the adoption has not been universal in all English-speaking countries. The metric system was first implemented during the French Revolution with just the metre and kilogram as standards of length, in the 1830s Carl Friedrich Gauss laid the foundations for a coherent system based on length, mass, and time. In the 1860s a group working under the auspices of the British Association for the Advancement of Science formulated the requirement for a coherent system of units with base units and derived units. Meanwhile, in 1875, the Treaty of the Metre passed responsibility for verification of the kilogram, in 1921, the Treaty was extended to include all physical quantities including electrical units originally defined in 1893. The units associated with these quantities were the metre, kilogram, second, ampere, kelvin, in 1971, a seventh base quantity, amount of substance represented by the mole, was added to the definition of SI. On 11 July 1792, the proposed the names metre, are, litre and grave for the units of length, area, capacity. The committee also proposed that multiples and submultiples of these units were to be denoted by decimal-based prefixes such as centi for a hundredth, on 10 December 1799, the law by which the metric system was to be definitively adopted in France was passed. Prior to this, the strength of the magnetic field had only been described in relative terms. The technique used by Gauss was to equate the torque induced on a magnet of known mass by the earth’s magnetic field with the torque induced on an equivalent system under gravity. The resultant calculations enabled him to assign dimensions based on mass, length, a French-inspired initiative for international cooperation in metrology led to the signing in 1875 of the Metre Convention. Initially the convention only covered standards for the metre and the kilogram, one of each was selected at random to become the International prototype metre and International prototype kilogram that replaced the mètre des Archives and kilogramme des Archives respectively. Each member state was entitled to one of each of the prototypes to serve as the national prototype for that country. Initially its prime purpose was a periodic recalibration of national prototype metres. The official language of the Metre Convention is French and the version of all official documents published by or on behalf of the CGPM is the French-language version
24.
Joule
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The joule, symbol J, is a derived unit of energy in the International System of Units. It is equal to the transferred to an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre. It is also the energy dissipated as heat when a current of one ampere passes through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule, one joule can also be defined as, The work required to move an electric charge of one coulomb through an electrical potential difference of one volt, or one coulomb volt. This relationship can be used to define the volt, the work required to produce one watt of power for one second, or one watt second. This relationship can be used to define the watt and this SI unit is named after James Prescott Joule. As with every International System of Units unit named for a person, note that degree Celsius conforms to this rule because the d is lowercase. — Based on The International System of Units, section 5.2. The CGPM has given the unit of energy the name Joule, the use of newton metres for torque and joules for energy is helpful to avoid misunderstandings and miscommunications. The distinction may be also in the fact that energy is a scalar – the dot product of a vector force. By contrast, torque is a vector – the cross product of a distance vector, torque and energy are related to one another by the equation E = τ θ, where E is energy, τ is torque, and θ is the angle swept. Since radians are dimensionless, it follows that torque and energy have the same dimensions, one joule in everyday life represents approximately, The energy required to lift a medium-size tomato 1 m vertically from the surface of the Earth. The energy released when that same tomato falls back down to the ground, the energy required to accelerate a 1 kg mass at 1 m·s−2 through a 1 m distance in space. The heat required to raise the temperature of 1 g of water by 0.24 °C, the typical energy released as heat by a person at rest every 1/60 s. The kinetic energy of a 50 kg human moving very slowly, the kinetic energy of a 56 g tennis ball moving at 6 m/s. The kinetic energy of an object with mass 1 kg moving at √2 ≈1.4 m/s, the amount of electricity required to light a 1 W LED for 1 s. Since the joule is also a watt-second and the unit for electricity sales to homes is the kW·h. For additional examples, see, Orders of magnitude The zeptojoule is equal to one sextillionth of one joule,160 zeptojoules is equivalent to one electronvolt. The nanojoule is equal to one billionth of one joule, one nanojoule is about 1/160 of the kinetic energy of a flying mosquito
25.
Kilojoule
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The joule, symbol J, is a derived unit of energy in the International System of Units. It is equal to the transferred to an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre. It is also the energy dissipated as heat when a current of one ampere passes through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule, one joule can also be defined as, The work required to move an electric charge of one coulomb through an electrical potential difference of one volt, or one coulomb volt. This relationship can be used to define the volt, the work required to produce one watt of power for one second, or one watt second. This relationship can be used to define the watt and this SI unit is named after James Prescott Joule. As with every International System of Units unit named for a person, note that degree Celsius conforms to this rule because the d is lowercase. — Based on The International System of Units, section 5.2. The CGPM has given the unit of energy the name Joule, the use of newton metres for torque and joules for energy is helpful to avoid misunderstandings and miscommunications. The distinction may be also in the fact that energy is a scalar – the dot product of a vector force. By contrast, torque is a vector – the cross product of a distance vector, torque and energy are related to one another by the equation E = τ θ, where E is energy, τ is torque, and θ is the angle swept. Since radians are dimensionless, it follows that torque and energy have the same dimensions, one joule in everyday life represents approximately, The energy required to lift a medium-size tomato 1 m vertically from the surface of the Earth. The energy released when that same tomato falls back down to the ground, the energy required to accelerate a 1 kg mass at 1 m·s−2 through a 1 m distance in space. The heat required to raise the temperature of 1 g of water by 0.24 °C, the typical energy released as heat by a person at rest every 1/60 s. The kinetic energy of a 50 kg human moving very slowly, the kinetic energy of a 56 g tennis ball moving at 6 m/s. The kinetic energy of an object with mass 1 kg moving at √2 ≈1.4 m/s, the amount of electricity required to light a 1 W LED for 1 s. Since the joule is also a watt-second and the unit for electricity sales to homes is the kW·h. For additional examples, see, Orders of magnitude The zeptojoule is equal to one sextillionth of one joule,160 zeptojoules is equivalent to one electronvolt. The nanojoule is equal to one billionth of one joule, one nanojoule is about 1/160 of the kinetic energy of a flying mosquito
26.
Metric system
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The metric system is an internationally agreed decimal system of measurement. Many sources also cite Liberia and Myanmar as the other countries not to have done so. Although the originators intended to devise a system that was accessible to all. Control of the units of measure was maintained by the French government until 1875, when it was passed to an intergovernmental organisation. From its beginning, the features of the metric system were the standard set of interrelated base units. These base units are used to larger and smaller units that could replace a huge number of other units of measure in existence. Although the system was first developed for use, the development of coherent units of measure made it particularly suitable for science. Although the metric system has changed and developed since its inception, designed for transnational use, it consisted of a basic set of units of measurement, now known as base units. At the outbreak of the French Revolution in 1789, most countries, the metric system was designed to be universal—in the words of the French philosopher Marquis de Condorcet it was to be for all people for all time. However, these overtures failed and the custody of the metric system remained in the hands of the French government until 1875. In languages where the distinction is made, unit names are common nouns, the concept of using consistent classical names for the prefixes was first proposed in a report by the Commission on Weights and Measures in May 1793. The prefix kilo, for example, is used to multiply the unit by 1000, thus the kilogram and kilometre are a thousand grams and metres respectively, and a milligram and millimetre are one thousandth of a gram and metre respectively. These relations can be written symbolically as,1 mg =0, however,1935 extensions to the prefix system did not follow this convention, the prefixes nano- and micro-, for example have Greek roots. During the 19th century the prefix myria-, derived from the Greek word μύριοι, was used as a multiplier for 10000, prefixes are not usually used to indicate multiples of a second greater than 1, the non-SI units of minute, hour and day are used instead. On the other hand, prefixes are used for multiples of the unit of volume. The base units used in the system must be realisable. Each of the units in SI is accompanied by a mise en pratique published by the BIPM that describes in detail at least one way in which the base unit can be measured. In practice, such realisation is done under the auspices of a mutual acceptance arrangement, in the original version of the metric system the base units could be derived from a specified length and the weight of a specified volume of pure water
27.
Chemistry
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Chemistry is a branch of physical science that studies the composition, structure, properties and change of matter. Chemistry is sometimes called the science because it bridges other natural sciences, including physics. For the differences between chemistry and physics see comparison of chemistry and physics, the history of chemistry can be traced to alchemy, which had been practiced for several millennia in various parts of the world. The word chemistry comes from alchemy, which referred to a set of practices that encompassed elements of chemistry, metallurgy, philosophy, astrology, astronomy, mysticism. An alchemist was called a chemist in popular speech, and later the suffix -ry was added to this to describe the art of the chemist as chemistry, the modern word alchemy in turn is derived from the Arabic word al-kīmīā. In origin, the term is borrowed from the Greek χημία or χημεία and this may have Egyptian origins since al-kīmīā is derived from the Greek χημία, which is in turn derived from the word Chemi or Kimi, which is the ancient name of Egypt in Egyptian. Alternately, al-kīmīā may derive from χημεία, meaning cast together, in retrospect, the definition of chemistry has changed over time, as new discoveries and theories add to the functionality of the science. The term chymistry, in the view of noted scientist Robert Boyle in 1661, in 1837, Jean-Baptiste Dumas considered the word chemistry to refer to the science concerned with the laws and effects of molecular forces. More recently, in 1998, Professor Raymond Chang broadened the definition of chemistry to mean the study of matter, early civilizations, such as the Egyptians Babylonians, Indians amassed practical knowledge concerning the arts of metallurgy, pottery and dyes, but didnt develop a systematic theory. Greek atomism dates back to 440 BC, arising in works by such as Democritus and Epicurus. In 50 BC, the Roman philosopher Lucretius expanded upon the theory in his book De rerum natura, unlike modern concepts of science, Greek atomism was purely philosophical in nature, with little concern for empirical observations and no concern for chemical experiments. Work, particularly the development of distillation, continued in the early Byzantine period with the most famous practitioner being the 4th century Greek-Egyptian Zosimos of Panopolis. He formulated Boyles law, rejected the four elements and proposed a mechanistic alternative of atoms. Before his work, though, many important discoveries had been made, the Scottish chemist Joseph Black and the Dutchman J. B. English scientist John Dalton proposed the theory of atoms, that all substances are composed of indivisible atoms of matter. Davy discovered nine new elements including the alkali metals by extracting them from their oxides with electric current, british William Prout first proposed ordering all the elements by their atomic weight as all atoms had a weight that was an exact multiple of the atomic weight of hydrogen. The inert gases, later called the noble gases were discovered by William Ramsay in collaboration with Lord Rayleigh at the end of the century, thereby filling in the basic structure of the table. Organic chemistry was developed by Justus von Liebig and others, following Friedrich Wöhlers synthesis of urea which proved that organisms were, in theory
28.
Physics
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Physics is the natural science that involves the study of matter and its motion and behavior through space and time, along with related concepts such as energy and force. One of the most fundamental disciplines, the main goal of physics is to understand how the universe behaves. Physics is one of the oldest academic disciplines, perhaps the oldest through its inclusion of astronomy, Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry, and the boundaries of physics are not rigidly defined. New ideas in physics often explain the mechanisms of other sciences while opening new avenues of research in areas such as mathematics. Physics also makes significant contributions through advances in new technologies that arise from theoretical breakthroughs, the United Nations named 2005 the World Year of Physics. Astronomy is the oldest of the natural sciences, the stars and planets were often a target of worship, believed to represent their gods. While the explanations for these phenomena were often unscientific and lacking in evidence, according to Asger Aaboe, the origins of Western astronomy can be found in Mesopotamia, and all Western efforts in the exact sciences are descended from late Babylonian astronomy. The most notable innovations were in the field of optics and vision, which came from the works of many scientists like Ibn Sahl, Al-Kindi, Ibn al-Haytham, Al-Farisi and Avicenna. The most notable work was The Book of Optics, written by Ibn Al-Haitham, in which he was not only the first to disprove the ancient Greek idea about vision, but also came up with a new theory. In the book, he was also the first to study the phenomenon of the pinhole camera, many later European scholars and fellow polymaths, from Robert Grosseteste and Leonardo da Vinci to René Descartes, Johannes Kepler and Isaac Newton, were in his debt. Indeed, the influence of Ibn al-Haythams Optics ranks alongside that of Newtons work of the same title, the translation of The Book of Optics had a huge impact on Europe. From it, later European scholars were able to build the devices as what Ibn al-Haytham did. From this, such important things as eyeglasses, magnifying glasses, telescopes, Physics became a separate science when early modern Europeans used experimental and quantitative methods to discover what are now considered to be the laws of physics. Newton also developed calculus, the study of change, which provided new mathematical methods for solving physical problems. The discovery of new laws in thermodynamics, chemistry, and electromagnetics resulted from greater research efforts during the Industrial Revolution as energy needs increased, however, inaccuracies in classical mechanics for very small objects and very high velocities led to the development of modern physics in the 20th century. Modern physics began in the early 20th century with the work of Max Planck in quantum theory, both of these theories came about due to inaccuracies in classical mechanics in certain situations. Quantum mechanics would come to be pioneered by Werner Heisenberg, Erwin Schrödinger, from this early work, and work in related fields, the Standard Model of particle physics was derived. Areas of mathematics in general are important to this field, such as the study of probabilities, in many ways, physics stems from ancient Greek philosophy
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European Union
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The European Union is a political and economic union of 28 member states that are located primarily in Europe. It has an area of 4,475,757 km2, the EU has developed an internal single market through a standardised system of laws that apply in all member states. Within the Schengen Area, passport controls have been abolished, a monetary union was established in 1999 and came into full force in 2002, and is composed of 19 EU member states which use the euro currency. The EU operates through a system of supranational and intergovernmental decision-making. The EU traces its origins from the European Coal and Steel Community, the community and its successors have grown in size by the accession of new member states and in power by the addition of policy areas to its remit. While no member state has left the EU or its antecedent organisations, the Maastricht Treaty established the European Union in 1993 and introduced European citizenship. The latest major amendment to the basis of the EU. The EU as a whole is the largest economy in the world, additionally,27 out of 28 EU countries have a very high Human Development Index, according to the United Nations Development Programme. In 2012, the EU was awarded the Nobel Peace Prize, through the Common Foreign and Security Policy, the EU has developed a role in external relations and defence. The union maintains permanent diplomatic missions throughout the world and represents itself at the United Nations, the World Trade Organization, the G7, because of its global influence, the European Union has been described as an emerging superpower. After World War II, European integration was seen as an antidote to the nationalism which had devastated the continent. 1952 saw the creation of the European Coal and Steel Community, the supporters of the Community included Alcide De Gasperi, Jean Monnet, Robert Schuman, and Paul-Henri Spaak. These men and others are credited as the Founding fathers of the European Union. In 1957, Belgium, France, Italy, Luxembourg, the Netherlands and West Germany signed the Treaty of Rome and they also signed another pact creating the European Atomic Energy Community for co-operation in developing nuclear energy. Both treaties came into force in 1958, the EEC and Euratom were created separately from the ECSC, although they shared the same courts and the Common Assembly. The EEC was headed by Walter Hallstein and Euratom was headed by Louis Armand, Euratom was to integrate sectors in nuclear energy while the EEC would develop a customs union among members. During the 1960s, tensions began to show, with France seeking to limit supranational power, Jean Rey presided over the first merged Commission. In 1973, the Communities enlarged to include Denmark, Ireland, Norway had negotiated to join at the same time, but Norwegian voters rejected membership in a referendum
30.
Nutrition facts label
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The nutrition facts label is a label required on most packaged food in many countries. Most countries also release overall nutrition guides for general educational purposes, in some cases, the guides are based on different dietary targets for various nutrients than the labels on specific foods. Australia and New Zealand use an information panel of the following format, Other items are included as appropriate. In April 2013 the New Zealand government introduced rules around common claims made on food packaging, in Canada, a standardized Nutrition Facts label was introduced as part of regulations passed in 2003, and became mandatory for most prepackaged food products on December 12,2005. In accordance with food packaging laws in the country, all information, including the nutrition label, canadian regulation tightly controls the manner in which the nutrition fact table data are laid out. There is a variety of possible formats for use on a given food package. A selection hierarchy is used to select among the many formats and this results in standard formats being considered for use before horizontal and linear formats. The selection hierarchy also allows the NFT to occupy no more than 15% of the packages available display area. In practice, determining the ADS of a package, and selecting the appropriate NFT format, a new regulation is now in force. Nutritional labelling becomes mandatory for most pre-packaged foods as from December 2016, in the European Union, along the old rules, the information is most often labelled Nutrition Information. An example is shown on the right, the panel is optional, but if provided, the prescribed content and format must be followed. It will always give values for a set quantity —100 g or 100 ml of the product — and often also for a defined serving, first will come the energy values, in both kilocalories and kilojoules. Then will come a breakdown of constituent elements, usually most or all of protein, carbohydrate, starch, sugar, fat, fibre and sodium. The fat figure is likely to be broken down into saturated and unsaturated fat. With regards to health claims and nutrition claims, these are harmonised in the EU through Regulation 1924/2006, in November 2012, the European Commission published two new regulations, Regulation No. Certain nutrition claim groups as of Regulation No 1924/2006 had to be changed, moreover, the health claims associated to barley beta-gluten were amended. Within Regulation 1924, there are definitions of terms such as low fat, high fibre. All health claims have been harmonised in the European Union and they can be used if they have been approved by EFSA
31.
Energy density
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Energy density is the amount of energy stored in a given system or region of space per unit volume. Colloquially it may also be used for energy per unit mass, often only the useful or extractable energy is measured, which is to say that chemically inaccessible energy such as rest mass energy is ignored. In short, pressure is a measure of the enthalpy per unit volume of a system, a pressure gradient has a potential to perform work on the surroundings by converting enthalpy until equilibrium is reached. There are many different types of stored in materials. In order of the magnitude of the energy released, these types of reactions are, nuclear, chemical, electrochemical. Chemical reactions are used by animals to derive energy from food, electrochemical reactions are used by most mobile devices such as laptop computers and mobile phones to release the energy from batteries. The following is a list of the energy densities of commonly used or well-known energy storage materials. Note that this list does not consider the mass of reactants commonly available such as the oxygen required for combustion or the efficiency in use. The following unit conversions may be helpful when considering the data in the table,1 MJ ≈0.28 kWh ≈0.37 HPh. In energy storage applications the energy density relates the mass of a store to the volume of the storage facility. The higher the density of the fuel, the more energy may be stored or transported for the same amount of volume. The energy density of a fuel per unit mass is called the energy of that fuel. The greatest energy source by far is mass itself and this energy, E = mc2, where m = ρV, ρ is the mass per unit volume, V is the volume of the mass itself and c is the speed of light. This energy, however, can be released only by the processes of nuclear fission, nuclear fusion, nuclear reactions cannot be realized by chemical reactions such as combustion. Although greater matter densities can be achieved, the density of a star would approximate the most dense system capable of matter-antimatter annihilation possible. A black hole, although denser than a star, does not have an equivalent anti-particle form. In the case of small black holes the power output would be tremendous. The highest density sources of energy aside from antimatter are fusion and fission, fusion includes energy from the sun which will be available for billions of years but so far, sustained fusion power production continues to be elusive
32.
Lactose
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Lactose is a disaccharide sugar composed of galactose and glucose that is found in milk. Lactose makes up around 2–8% of milk, although the amount varies among species and individuals and it is extracted from sweet or sour whey. The name comes from lac, the Latin word for milk and it has a formula of C12H22O11 and the hydrate formula C12H22O11·H2O, making it an isomer of sucrose. The first crude isolation of lactose, by Italian physician Fabrizio Bartoletti, was published in 1633, in 1700, the Venetian pharmacist Lodovico Testi published a booklet of testimonials to the power of milk sugar to relieve, among other ailments, the symptoms of arthritis. In 1715, Testis procedure for making milk sugar was published by Antonio Vallisneri, lactose was identified as a sugar in 1780 by Carl Wilhelm Scheele. In 1812, Heinrich Vogel recognized that glucose was a product of hydrolyzing lactose, in 1856, Louis Pasteur crystallized the other component of lactose, galactose. By 1894, Emil Fischer had established the configurations of the component sugars, lactose was named by the French chemist Jean Baptiste André Dumas in 1843. Lactose is a derived from the condensation of galactose and glucose. Lactose is hydrolysed to glucose and galactose, isomerised in alkaline solution to lactulose, lactose monohydrate crystals have a characteristic tomahawk shape that can be observed with a light microscope. Several million tons are produced annually as a by-product of the dairy industry, whey is made up of 6. 5% solids of which 4. 8% is lactose that may be purified by crystallisation. Whey or milk plasma is the liquid remaining after milk is curdled and strained, lactose makes up about 2–8% of milk by weight. Industrially, lactose is produced from whey permeate – that is whey filtrated for all major proteins, the protein fraction is used in infant nutrition and sport nutrition while the permeate can be evaporated to 60–65% solids and crystallized while cooling. Lactose can also be precipitated from whey using ethanol, since it is insoluble in ethanol, lactose precipitates, in about 65% yield. Infant mammals nurse on their mothers to drink milk, which is rich in lactose, the intestinal villi secrete the enzyme called lactase to digest it. This enzyme cleaves the molecule into its two subunits, the simple sugars glucose and galactose, which can be absorbed. Since lactose occurs mostly in milk, in most mammals, the production of lactase gradually decreases with maturity due to a lack of continuing consumption. Many people with ancestry in Europe, West Asia, South Asia, the Sahel belt in West Africa, East Africa, in many of these areas, milk from mammals such as cattle, goats, and sheep is used as a large source of food. Hence, it was in these regions that genes for lifelong lactase production first evolved, the genes of adult lactose tolerance have evolved independently in various ethnic groups
33.
Sugar alcohol
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Sugar alcohols are organic compounds, typically derived from sugars, that comprise a class of polyols. Contrary to what the name may suggest, an alcohol is neither a sugar nor an alcoholic beverage. They are white, water-soluble solids that can occur naturally or be produced industrially from sugars and they are used widely in the food industry as thickeners and sweeteners. In commercial foodstuffs, sugar alcohols are used in place of table sugar. Xylitol is perhaps the most popular sugar alcohol due to its similarity to sucrose in visual appearance, sugar alcohols have the general formula HOCH2nCH2OH. In contrast, sugars have two hydrogen atoms, for example HOCH2nCHO or HOCH2n−1CCH2OH. The sugar alcohols differ in chain length, most have five- or six-carbon chains, because they are derived from pentoses and hexoses, respectively. They have one OH group attached to each carbon and they are further differentiated by the relative orientation of these OH groups. Unlike sugars, which tend to exist as rings, sugar alcohols do not and they can however be dehydrated to give cyclic ethers, e. g. sorbitol can be dehydrated to isosorbide. Sugar alcohols occur naturally and at one time, mannitol was obtained from natural sources, today, they are often obtained by hydrogenation of sugars, using Raney nickel catalysts. The conversion of glucose and mannose to sorbitol and mannitol is given, xylitol and lacticol are obtained similarly. Erythritol on the hand is obtained by fermentation of glucose and sucrose. Sugar alcohols do not contribute to tooth decay, consumption of sugar alcohols affects blood sugar levels, although less than of sucrose. Sugar alcohols, with the exception of erythritol, may cause bloating. The simplest sugar alcohol, ethylene glycol, is sweet but notoriously toxic, the more complex sugar alcohols are for the most part nontoxic. As a group, sugar alcohols are not as sweet as sucrose and their flavor is like sucrose, and they can be used to mask the unpleasant aftertastes of some high intensity sweeteners. Sugar alcohols are not metabolized by bacteria, and so they do not contribute to tooth decay. They do not brown or caramelize when heated, in addition to their sweetness, some sugar alcohols can produce a noticeable cooling sensation in the mouth when highly concentrated, for instance in sugar-free hard candy or chewing gum
34.
Gibbs free energy
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Just as in mechanics, where the decrease in potential energy is defined as maximum useful work that can be performed, similarly different potentials have different meanings. The Gibbs energy is also the potential that is minimized when a system reaches chemical equilibrium at constant pressure and temperature. Its derivative with respect to the coordinate of the system vanishes at the equilibrium point. As such, a reduction in G is a condition for the spontaneity of processes at constant pressure and temperature. The Gibbs free energy, originally called available energy, was developed in the 1870s by the American scientist Josiah Willard Gibbs. The initial state of the body, according to Gibbs, is supposed to be such that the body can be made to pass from it to states of dissipated energy by reversible processes. In his 1876 magnum opus On the Equilibrium of Heterogeneous Substances, according to the second law of thermodynamics, for systems reacting at STP, there is a general natural tendency to achieve a minimum of the Gibbs free energy. A quantitative measure of the favorability of a reaction at constant temperature and pressure is the change ΔG in Gibbs free energy that is caused by the reaction. As a necessary condition for the reaction to occur at constant temperature and pressure, ΔG must be smaller than the non-PV work, ΔG equals the maximum amount of non-PV work that can be performed as a result of the chemical reaction for the case of reversible process. The equation can be seen from the perspective of the system taken together with its surroundings. First assume that the reaction at constant temperature and pressure is the only one that is occurring. Then the entropy released or absorbed by the system equals the entropy that the environment must absorb or release, the reaction will only be allowed if the total entropy change of the universe is zero or positive. This is reflected in a negative ΔG, and the reaction is called exergonic, if we couple reactions, then an otherwise endergonic chemical reaction can be made to happen. In traditional use, the term free was included in Gibbs free energy to mean available in the form of useful work, the characterization becomes more precise if we add the qualification that it is the energy available for non-volume work. However, a number of books and journal articles do not include the attachment free. This is the result of a 1988 IUPAC meeting to set unified terminologies for the scientific community. This standard, however, has not yet been universally adopted. Further, Gibbs stated, In this description, as used by Gibbs, ε refers to the energy of the body, η refers to the entropy of the body
35.
Adenosine triphosphate
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Adenosine triphosphate is a nucleotide, also called a nucleoside triphosphate, is a small molecule used in cells as a coenzyme. It is often referred to as the unit of currency of intracellular energy transfer. ATP transports chemical energy within cells for metabolism, most cellular functions need energy in order to be carried out, synthesis of proteins, synthesis of membranes, movement of the cell, cellular division, transport of various solutes etc. The ATP is the molecule that carries energy to the place where the energy is needed, when ATP breaks into ADP and Pi, the breakdown of the last covalent link of phosphate liberates energy that is used in reactions where it is needed. Substrate-level phosphorylation, oxidative phosphorylation in cellular respiration, and photophosphorylation in photosynthesis are three mechanisms of ATP biosynthesis. Metabolic processes that use ATP as an energy source convert it back into its precursors, ATP is therefore continuously recycled in organisms, the human body, which on average contains only 250 grams of ATP, turns over its own body weight equivalent in ATP each day. ATP is used as a substrate in signal transduction pathways by kinases that phosphorylate proteins and it is also used by adenylate cyclase, which uses ATP to produce the second messenger molecule cyclic AMP. The ratio between ATP and AMP is used as a way for a cell to sense how much energy is available and control the metabolic pathways that produce and consume ATP. Apart from its roles in signaling and energy metabolism, ATP is also incorporated into nucleic acids by polymerases in the process of transcription, ATP is the neurotransmitter believed to signal the sense of taste. The structure of this consists of a purine base attached by the 9′ nitrogen atom to the 1′ carbon atom of a pentose sugar. Three phosphate groups are attached at the 5′ carbon atom of the pentose sugar and it is the addition and removal of these phosphate groups that inter-convert ATP, ADP and AMP. When ATP is used in DNA synthesis, the sugar is first converted to deoxyribose by ribonucleotide reductase. ATP was discovered in 1929 by Karl Lohmann, and independently by Cyrus Fiske and Yellapragada Subbarow of Harvard Medical School and it was proposed to be the intermediary molecule between energy-yielding and energy-requiring reactions in cells by Fritz Albert Lipmann in 1941. It was first artificially synthesized by Alexander Todd in 1948, ATP consists of adenosine – composed of an adenine ring and a ribose sugar – and three phosphate groups. The phosphoryl groups, starting with the group closest to the ribose, are referred to as the alpha, beta, consequently, it is closely related to the adenosine nucleotide, a monomer of RNA. ATP is highly soluble in water and is stable in solutions between pH6.8 and 7.4, but is rapidly hydrolysed at extreme pH. Consequently, ATP is best stored as an anhydrous salt, ATP is an unstable molecule in unbuffered water, in which it hydrolyses to ADP and phosphate. This is because the strength of the bonds between the groups in ATP is less than the strength of the hydrogen bonds, between its products, and water
36.
Calorimeter
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A calorimeter is an object used for calorimetry, or the process of measuring the heat of chemical reactions or physical changes as well as heat capacity. Differential scanning calorimeters, isothermal microcalorimeters, titration calorimeters and accelerated rate calorimeters are among the most common types, a simple calorimeter just consists of a thermometer attached to a metal container full of water suspended above a combustion chamber. To find the enthalpy change per mole of a substance A in a reaction between two substances A and B, the substances are added to a calorimeter and the initial and final temperatures are noted. Multiplying the temperature change by the mass and specific heat capacities of the substances gives a value for the energy given off or absorbed during the reaction, dividing the energy change by how many moles of A were present gives its enthalpy change of reaction. This method is used primarily in teaching as it describes the theory of calorimetry. It does not account for the loss through the container or the heat capacity of the thermometer and container itself. The name calorimeter was made up by Antoine Lavoisier, in 1780, he used a guinea pig in his experiments with this device to measure heat production. The heat from the guinea pigs respiration melted snow surrounding the calorimeter, showing that respiratory gas exchange is combustion, an adiabatic calorimeter is a calorimeter used to examine a runaway reaction. Since the calorimeter runs in an environment, any heat generated by the material sample under test causes the sample to increase in temperature. No adiabatic calorimeter is fully adiabatic - some heat will be lost by the sample to the sample holder, a mathematical correction factor, known as the phi-factor, can be used to adjust the calorimetric result to account for these heat losses. The phi-factor is the ratio of the mass of the sample and sample holder to the thermal mass of the sample alone. A reaction calorimeter is a calorimeter in which a reaction is initiated within a closed insulated container. Reaction heats are measured and the heat is obtained by integrating heatflow versus time. This is the used in industry to measure heats since industrial processes are engineered to run at constant temperatures. Reaction calorimetry can also be used to determine maximum heat release rate for chemical process engineering, there are four main methods for measuring the heat in reaction calorimeter, The cooling/heating jacket controls either the temperature of the process or the temperature of the jacket. Heat is measured by monitoring the temperature difference between heat transfer fluid and the process fluid, in addition, fill volumes, specific heat, heat transfer coefficient have to be determined to arrive at a correct value. It is possible with this type of calorimeter to do reactions at reflux, the cooling/heating jacket controls the temperature of the process. Heat is measured by monitoring the heat gained or lost by the transfer fluid
37.
Urea
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Urea, also known as carbamide, is an organic compound with the chemical formula CO2. This amide has two groups joined by a carbonyl functional group. Urea serves an important role in the metabolism of nitrogen-containing compounds by animals and is the main nitrogen-containing substance in the urine of mammals and it is a colorless, odorless solid, highly soluble in water, and practically non-toxic. Dissolved in water, it is neither acidic nor alkaline, the body uses it in many processes, most notably nitrogen excretion. The liver forms it by combining two molecules with a carbon dioxide molecule in the urea cycle. Urea is widely used in fertilizers as a source of nitrogen and is an important raw material for the chemical industry, Friedrich Wöhlers discovery in 1828 that urea can be produced from inorganic starting materials was an important conceptual milestone in chemistry. More than 90% of world production of urea is destined for use as a nitrogen-release fertilizer. Urea has the highest nitrogen content of all solid nitrogenous fertilizers in common use, therefore, it has the lowest transportation costs per unit of nitrogen nutrient. The standard crop-nutrient rating of urea is 46-0-0, many soil bacteria possess the enzyme urease, which catalyzes conversion of urea to ammonia or ammonium ion and bicarbonate ion. Thus urea fertilizers rapidly transform to the form in soils. Ammonium and nitrate are readily absorbed by plants, and are the dominant sources of nitrogen for plant growth, Urea is also used in many multi-component solid fertilizer formulations. Urea is highly soluble in water and is also very suitable for use in fertilizer solutions. For fertilizer use, granules are preferred over prills because of their particle size distribution. The most common impurity of synthetic urea is biuret, which impairs plant growth, Urea is usually spread at rates of between 40 and 300 kg/ha but rates vary. Smaller applications incur lower losses due to leaching, during summer, urea is often spread just before or during rain to minimize losses from volatilization. Because of the nitrogen concentration in urea, it is very important to achieve an even spread. The application equipment must be calibrated and properly used. Drilling must not occur on contact with or close to seed, Urea dissolves in water for application as a spray or through irrigation systems
38.
Wilbur Olin Atwater
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Wilbur Olin Atwater was an American chemist known for his studies of human nutrition and metabolism. He is credited with developing the Atwater system, laying the groundwork, in the 19th century, for the science of nutrition in the United States, Atwater was born in Johnsburg, New York and grew up in the New England area. He opted not to fight in the American Civil War and instead to pursue a degree at Wesleyan University in Connecticut. Atwater received his doctorate in 1869 in agricultural chemistry, his thesis being entitled The Proximate Composition of Several Types of American Maize, afterwards, he spent two years in Leipzig and Berlin, where he visited agricultural experiment stations. Atwater also spent time traveling throughout Scotland, Rome, and Naples, Atwater later returned to the United States to teach at East Tennessee University and later Wesleyan as its first Professor of Chemistry. His granddaughter Catherine Merriam Atwater married economist John Kenneth Galbraith, Atwater is best known for his studies of human nutrition. Maintained in the basement of Judd Hall, the 4- by 8-foot chamber housed a machine that measured human oxygen intake, with annual costs exceeding $10 thousand, the respiration calorimeter was considered a dream project for the 19th century. Atwater began the first of about 500 experiments in 1896, in fact, he made history by establishing America’s first state agricultural experiment station at. He studied respiration and metabolism in animals and in humans, the calorimeter aided studies in food analysis, dietary evolution, work energy consumption, and digestible foods. It measured the human metabolism balance by analyzing the heat produced, with this machine, the dynamics of metabolism could be quantified and the balance between food intake and energy output could be measured. Atwater applied the first law of thermodynamics to his research, Energy can be transformed, before Atwaters development of the respiration calorimeter, many experiments on calorie intake and expenditure had been conducted on animals. During this period, there was a widely held belief that the first law of thermodynamics applied to animals, Atwater demonstrated that whatever amount of consumed energy humans cannot use is left over and stored in the body. His findings thus established that the first law applied to humans as well as animals, Atwaters research and conclusions in this regard changed both how people thought about science and about humans. The results from Atwater’s calorimetry study influenced many areas of American life, most importantly, the calorimeter was a great influence to the growing awareness of the food calorie as a unit of measure both in terms of consumption and metabolism. Atwater reported on the weight of the calorie as a means to measure the efficiency of a diet and he stated different types of food produced different amounts of energy. He stressed the importance of an inexpensive and efficient diet that included more proteins, beans and his careful studies of nutrition and those that followed helped spur federal policies that have done much to alleviate childhood hunger. We see reflections of his influence on the labels of products in our grocery stores, today’s familiar food pyramid, a quick and easy visual guide to the recommended daily intake of food, is a tribute to Atwater and his successors. Atwater also studied the effect of alcohol on the body and his findings showed humans generated heat from alcohol just as they generated heat from a carbohydrate
39.
Lipid
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In biology, lipids comprise a group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins, monoglycerides, diglycerides, triglycerides, phospholipids, and others. The main biological functions of lipids include storing energy, signaling, lipids have applications in the cosmetic and food industries as well as in nanotechnology. Biological lipids originate entirely or in part from two types of biochemical subunits or building-blocks, ketoacyl and isoprene groups. Although the term lipid is sometimes used as a synonym for fats, fats are a subgroup of lipids called triglycerides, lipids also encompass molecules such as fatty acids and their derivatives, as well as other sterol-containing metabolites such as cholesterol. Although humans and other mammals use various biosynthetic pathways both to break down and to synthesize lipids, some essential lipids cannot be made this way, the word lipid stems etymologically from the Greek lipos. The fatty acid structure is one of the most fundamental categories of biological lipids, the carbon chain, typically between four and 24 carbons long, may be saturated or unsaturated, and may be attached to functional groups containing oxygen, halogens, nitrogen, and sulfur. If a fatty acid contains a double bond, there is the possibility of either a cis or trans geometric isomerism, cis-double bonds cause the fatty acid chain to bend, an effect that is compounded with more double bonds in the chain. This in turn plays an important role in the structure and function of cell membranes, most naturally occurring fatty acids are of the cis configuration, although the trans form does exist in some natural and partially hydrogenated fats and oils. Examples of biologically important fatty acids include the eicosanoids, derived primarily from arachidonic acid and eicosapentaenoic acid, that include prostaglandins, leukotrienes, docosahexaenoic acid is also important in biological systems, particularly with respect to sight. Other major lipid classes in the fatty acid category are the fatty esters, fatty esters include important biochemical intermediates such as wax esters, fatty acid thioester coenzyme A derivatives, fatty acid thioester ACP derivatives and fatty acid carnitines. The fatty amides include N-acyl ethanolamines, such as the cannabinoid neurotransmitter anandamide, glycerolipids are composed of mono-, di-, and tri-substituted glycerols, the best-known being the fatty acid triesters of glycerol, called triglycerides. The word triacylglycerol is sometimes used synonymously with triglyceride, in these compounds, the three hydroxyl groups of glycerol are each esterified, typically by different fatty acids. Because they function as a store, these lipids comprise the bulk of storage fat in animal tissues. The hydrolysis of the bonds of triglycerides and the release of glycerol. Additional subclasses of glycerolipids are represented by glycosylglycerols, which are characterized by the presence of one or more sugar residues attached to glycerol via a glycosidic linkage, examples of structures in this category are the digalactosyldiacylglycerols found in plant membranes and seminolipid from mammalian sperm cells. Glycerophospholipids, usually referred to as phospholipids, are ubiquitous in nature and are key components of the bilayer of cells, as well as being involved in metabolism. Neural tissue contains high amounts of glycerophospholipids, and alterations in their composition has been implicated in various neurological disorders. Examples of glycerophospholipids found in biological membranes are phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine, the major sphingoid base of mammals is commonly referred to as sphingosine
40.
United States Department of Agriculture
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Approximately 80% of USDAs $140 billion budget goes to the Food and Nutrition Service program. The largest component of the FNS budget is the Supplemental Nutrition Assistance Program, after the resignation of Thomas Vilsack on January 13,2017 and the departure of President Barack Obama from office on January 20,2017, the acting Secretary of Agriculture is Michael Young. Activities in this include the Supplemental Nutrition Assistance Program, which provides healthy food to over 40 million low-income. The USDA also is concerned with assisting farmers and food producers with the sale of crops and it plays a role in overseas aid programs by providing surplus foods to developing countries. This aid can go through USAID, foreign governments, international bodies such as World Food Program, the Agricultural Act of 1949, section 416 and Agricultural Trade Development and Assistance Act of 1954, also known as Food for Peace, provides the legal basis of such actions. The USDA is a partner of the World Cocoa Foundation, early in its history, the economy of the United States was largely agrarian. Officials in the government had long sought new and improved varieties of seeds, plants. In 1837 Henry Leavitt Ellsworth, a Yale-educated attorney interested in improving agriculture, became Commissioner of Patents and he began collecting and distributing new varieties of seeds and plants through members of the Congress and agricultural societies. In 1839, Congress established the Agricultural Division within the Patent Office and allotted $1,000 for the collection of agricultural statistics, Ellsworth was called the Father of the Department of Agriculture. In 1849, the Patent Office was transferred to the newly created Department of the Interior, in the ensuing years, agitation for a separate bureau of agriculture within the department or a separate department devoted to agriculture kept recurring. Lincoln called it the peoples department, in the 1880s, varied advocacy groups were lobbying for Cabinet representation. Business interests sought a Department of Commerce and Industry, and farmers tried to raise the Department of Agriculture to Cabinet rank, finally, on February 9,1889, President Grover Cleveland signed a bill into law elevating the Department of Agriculture to Cabinet level. In 1887, the Hatch Act provided for the funding of agricultural experiment stations in each state. The Smith-Lever Act of 1914 then funded cooperative extension services in each state to teach agriculture, home economics, with these and similar provisions, the USDA reached out to every county of every state. During the Great Depression, farming remained a way of life for millions of Americans. The Department of Agricultures Bureau of Home Economics, established in 1923, published shopping advice and recipes to stretch family budgets and make food go farther. USDA helped ensure that continued to be produced and distributed to those who needed it, assisted with loans for small landowners. The Department of Agriculture was authorized a budget for Fiscal Year 2015 of $139.7 billion, the Washington Post reports that he said There are days when I have literally nothing to do, he recalled thinking as he weighed his decision to quit
41.
Calorimetry
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Calorimetry is performed with a calorimeter. The word calorimetry is derived from the Latin word calor, meaning heat, scottish physician and scientist Joseph Black, who was the first to recognize the distinction between heat and temperature, is said to be the founder of the science of calorimetry. Indirect Calorimetry calculates heat that living organisms produce by measuring either their production of carbon dioxide and nitrogen waste, Lavoisier noted in 1780 that heat production can be predicted from oxygen consumption this way, using multiple regression. The Dynamic Energy Budget theory explains why this procedure is correct, Heat generated by living organisms may also be measured by direct calorimetry, in which the entire organism is placed inside the calorimeter for the measurement. A widely used instrument is the differential scanning calorimeter, a device which allows thermal data to be obtained on small amounts of material. It involves heating the sample at a rate and recording the heat flow either into or from the specimen. Calorimetry requires that a material that changes temperature have known definite thermal constitutive properties. There are many materials that do not comply with this rule, and for them, all increments are here required to be very small. This calculation refers to a domain of volume and temperature of the body in which no change occurs. An important assumption here is continuity of property relations, the surroundings pressure on the material is instrumentally adjusted to impose a chosen volume change, with initial volume V. To determine this latent heat, the change is effectively the independently instrumentally varied quantity. This latent heat is not one of the used ones. C V denotes the heat capacity, of the material at fixed constant volume V, while the pressure of the material is allowed to vary freely. The temperature is forced to change by exposure to a heat bath. It is customary to write C V simply as C V and this latent heat is one of the two widely used ones. The latent heat with respect to volume is the heat required for unit increment in volume at constant temperature and it can be said to be measured along an isotherm, and the pressure the material exerts is allowed to vary freely, according to its constitutive law p = p. For a given material, it can have a positive or negative sign or exceptionally it can be zero, the concept of latent heat with respect to volume was perhaps first recognized by Joseph Black in 1762. The term latent heat of expansion is also used, the latent heat with respect to volume can also be called the latent energy with respect to volume
42.
Dietary fiber
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Dietary fiber or roughage is the indigestible portion of food derived from plants. It has two components, Soluble fiber, which dissolves in water, is readily fermented in the colon into gases and physiologically active byproducts. It delays gastric emptying which in turn can cause a feeling of fullness. Insoluble fiber, which does not dissolve in water, is inert and provides bulking, or it can be prebiotic. Bulking fibers absorb water as they move through the digestive system, Dietary fibers can act by changing the nature of the contents of the gastrointestinal tract and by changing how other nutrients and chemicals are absorbed. Some types of soluble fiber absorb water to become a gelatinous, viscous substance which is fermented by bacteria in the digestive tract, some types of insoluble fiber have bulking action and are not fermented. Lignin, a major dietary insoluble fiber source, may alter the rate, other types of insoluble fiber, notably resistant starch, are fully fermented. A novel position has been adopted by the US Department of Agriculture to include functional fibers as isolated fiber sources that may be included in the diet, the term fiber is something of a misnomer, since many types of so-called dietary fiber are not actually fibrous. Food sources of fiber are often divided according to whether they provide soluble or insoluble fiber. Plant foods contain both types of fiber in varying degrees, according to the plants characteristics, a disadvantage of a diet high in fiber is the potential for significant intestinal gas production and bloating. Originally, fiber was defined to be the components of plants that resist human digestive enzymes, the definition was later changed to also include resistant starch, along with inulin and other oligosaccharides. Official definition of dietary fiber differs a little among different institutions, Dietary fibers are found in fruits, vegetables, the exact amount of fiber contained in the food can be seen in the following table of expected fiber in USDA food groups/subgroups Dietary fiber is found in plants. While all plants contain some fiber, plants with high concentrations are generally the most practical source. Fiber-rich plants can be eaten directly, or, alternatively, they can be used to make supplements and fiber-rich processed foods. The Academy of Nutrition and Dietetics, formerly the American Dietetic Association, some plants contain significant amounts of soluble and insoluble fiber. For example, plums and prunes have a thick skin covering a juicy pulp, the skin is a source of insoluble fiber, whereas soluble fiber is in the pulp. Grapes also contain an amount of fiber. The root of the plant, or glucomannan, produces results similar to fiber
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Protein
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Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, a linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide, short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides, or sometimes oligopeptides. The individual amino acid residues are bonded together by peptide bonds, the sequence of amino acid residues in a protein is defined by the sequence of a gene, which is encoded in the genetic code. In general, the code specifies 20 standard amino acids, however. Sometimes proteins have non-peptide groups attached, which can be called prosthetic groups or cofactors, proteins can also work together to achieve a particular function, and they often associate to form stable protein complexes. Once formed, proteins only exist for a period of time and are then degraded and recycled by the cells machinery through the process of protein turnover. A proteins lifespan is measured in terms of its half-life and covers a wide range and they can exist for minutes or years with an average lifespan of 1–2 days in mammalian cells. Abnormal and or misfolded proteins are degraded more rapidly due to being targeted for destruction or due to being unstable. Like other biological macromolecules such as polysaccharides and nucleic acids, proteins are essential parts of organisms, many proteins are enzymes that catalyse biochemical reactions and are vital to metabolism. Proteins also have structural or mechanical functions, such as actin and myosin in muscle and the proteins in the cytoskeleton, other proteins are important in cell signaling, immune responses, cell adhesion, and the cell cycle. In animals, proteins are needed in the diet to provide the essential amino acids that cannot be synthesized, digestion breaks the proteins down for use in the metabolism. Methods commonly used to study structure and function include immunohistochemistry, site-directed mutagenesis, X-ray crystallography, nuclear magnetic resonance. Most proteins consist of linear polymers built from series of up to 20 different L-α-amino acids, all proteinogenic amino acids possess common structural features, including an α-carbon to which an amino group, a carboxyl group, and a variable side chain are bonded. Only proline differs from this structure as it contains an unusual ring to the N-end amine group. The amino acids in a chain are linked by peptide bonds. Once linked in the chain, an individual amino acid is called a residue, and the linked series of carbon, nitrogen. The peptide bond has two forms that contribute some double-bond character and inhibit rotation around its axis, so that the alpha carbons are roughly coplanar
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Sugar substitute
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A sugar substitute is a food additive that provides a sweet taste like that of sugar while containing significantly less food energy. Some sugar substitutes are produced by nature, and others produced synthetically and those that are not produced by nature are, in general, called artificial sweeteners. An important class of sugar substitutes is known as high-intensity sweeteners and these are compounds with many times the sweetness of sucrose, common table sugar. As a result, much less sweetener is required and energy contribution is often negligible, the sensation of sweetness caused by these compounds is sometimes notably different from sucrose, so they are often used in complex mixtures that achieve the most natural sweet sensation. If the sucrose that is replaced has contributed to the texture of the product, in the United States, seven intensely sweet sugar substitutes have been approved for use. They are stevia, aspartame, sucralose, neotame, acesulfame potassium, saccharin, cyclamates are used outside the U. S. but have been prohibited in the U. S. since 1969. Others, which may or may not be approved depending on jurisdiction, include allulose, the U. S. Food and Drug Administration regulates artificial sweeteners as food additives. Food additives must be approved by the FDA, which publishes a generally recognized as safe list of additives, stevia is exempt under the FDAs GRAS policy due to its being a natural substance in wide use well before 1958, and the FDA has approved it on these grounds. The conclusions about safety are based on a review of a large body of information. The majority of sugar substitutes approved for use are artificially synthesized compounds. However, some bulk natural sugar substitutes are known, including sorbitol and xylitol, which are found in berries, fruit, vegetables and it is not commercially viable to extract these products from fruits and vegetables, so they are produced by catalytic hydrogenation of the appropriate reducing sugar. For example, xylose is converted to xylitol, lactose to lactitol, other natural substitutes are known, but these have yet to gain official approval for food use. Sorbitol and xylitol are examples of sugar alcohols and these are, in general, less sweet than sucrose but have similar bulk properties and can be used in a wide range of food products. Sometimes the sweetness profile is fine-tuned by mixing these with high-intensity sweeteners, as with all food products, the development of a formulation to replace sucrose is a complex proprietary process. This allows them to eat the foods they normally would while allowing them to lose weight. Dental care – Carbohydrates and sugars usually adhere to the tooth enamel, the bacteria convert the sugar to acids that decay the teeth. Sugar substitutes, unlike sugar, do not erode teeth as they are not fermented by the microflora of the dental plaque. A sweetener that can actually benefit dental health is xylitol, which tends to prevent bacteria from adhering to the surface, thus preventing plaque formation
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