1.
Japanese cuisine
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Japanese cuisine encompasses the regional and traditional foods of Japan, which have developed through centuries of social and economic changes. The traditional cuisine of Japan is based on rice with miso soup and other dishes, side dishes often consist of fish, pickled vegetables, and vegetables cooked in broth. Seafood is common, often grilled, but also served raw as sashimi or in sushi, seafood and vegetables are also deep-fried in a light batter, as tempura. Apart from rice, staples include noodles, such as soba, Japan also has many simmered dishes such as fish products in broth called oden, or beef in sukiyaki and nikujaga. Foreign food—in particular Chinese food like ramen, fried dumplings, and gyōza—as well as foods like curry, historically, the Japanese shunned meat, but with the modernization of Japan in the 1880s, meat-based dishes such as tonkatsu became common. Japanese cuisine, particularly sushi, has become popular throughout the world, as of 2011, Japan overtook France in number of Michelin-starred restaurants and has maintained the title since. Japanese cuisine is based on combining the staple food, which is steamed rice or gohan, with one or several okazu or main dishes. This may be accompanied by a clear or miso soup and tsukemono, the phrase ichijū-sansai refers to the makeup of a typical meal served, but has roots in classic kaiseki, honzen, and yūsoku cuisine. The term is used to describe the first course served in standard kaiseki cuisine nowadays. Rice is served in its own small bowl, and each item is placed on its own small plate or bowl for each individual portion. This is done even at home and it contrasts with the Western-style dinners at home, where each individual takes helpings from the large serving dishes of food presented at the middle of the dining table. Placing okazu on top of rice and soiling it is frowned upon by old-fashioned etiquette. The small rice bowl or chawan doubles as a word for the large tea bowls in tea ceremonies, thus in common speech, the drinking cup is referred to as yunomi-jawan or yunomi for the purpose of distinction. In the olden days, among the nobility, each course of a full-course Japanese meal would be brought on serving napkins called zen, which were originally platformed trays or small dining tables. In the modern age, faldstool trays or stackup-type legged trays may still be used in zashiki, i. e. tatami-mat rooms. Teishoku means a meal of fixed menu, a dinner à prix fixe served at shokudō or ryōriten, which is somewhat vague, defines it as fare served at teishoku dining hall, etc. Emphasis is placed on seasonality of food or shun, and dishes are designed to herald the arrival of the four seasons or calendar months, seasonality means taking advantage of the fruit of the mountains as well as the fruit of the sea as they come into season. Thus the first catch of skipjack tunas that arrives with the Kuroshio Current has traditionally been greatly prized, if something becomes available rather earlier than usual, the first crop or early catch is called hashiri
2.
Fermentation in food processing
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Fermentation in food processing is the process of converting carbohydrates to alcohol or organic acids using microorganisms—yeasts or bacteria—under anaerobic conditions. Fermentation usually implies that the action of microorganisms is desired, the science of fermentation is known as zymology or zymurgy. The term fermentation sometimes refers specifically to the conversion of sugars into ethanol, producing alcoholic drinks such as wine, beer. However, similar processes take place in the leavening of bread, other widely consumed fermented foods include vinegar, olives, and cheese. More localised foods prepared by fermentation may also be based on beans, grain, vegetables, fruit, honey, dairy products, fish, meat, since ancient times, humans have exploited the fermentation process. Seven-thousand-year-old jars containing the remains of wine, now on display at the University of Pennsylvania, were excavated in the Zagros Mountains in Iran. There is strong evidence that people were fermenting alcoholic drinks in Babylon c.3000 BC, ancient Egypt c.3150 BC, pre-Hispanic Mexico c.2000 BC, the French chemist Louis Pasteur founded zymology, when in 1856 he connected yeast to fermentation. When studying the fermentation of sugar to alcohol by yeast, Pasteur concluded that the fermentation was catalyzed by a force, called ferments. The ferments were thought to only within living organisms. Alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells, nevertheless, it was known that yeast extracts can ferment sugar even in the absence of living yeast cells. In 1907 he received the Nobel Prize in Chemistry for his research, one year earlier, in 1906, ethanol fermentation studies led to the early discovery of NAD+. Food fermentation is the conversion of sugars and other carbohydrates into alcohol or preservative organic acids, all three products have found human uses. The production of carbon dioxide is used to leaven bread, the production of organic acids is exploited to preserve and flavor vegetables and dairy products. It has more cases of botulism than any state in the United States of America. The World Health Organization has classified pickled foods as possibly carcinogenic, other research found that fermented food contains a carcinogenic by-product, ethyl carbamate. A2009 review of the studies conducted across Asia concluded that regularly eating pickled vegetables roughly doubles a persons risk for esophageal squamous cell carcinoma. Science aid, Fermentation - Process and uses of fermentation Fermented cereals, a global perspective - FAO1999
3.
Soybean
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Glycine max, commonly known as soybean in North America or soya bean, is a species of legume native to East Asia, widely grown for its edible bean which has numerous uses. The plant, classed as a rather than a pulse by the UN Food and Agriculture Organization. Fat-free soybean meal is a significant and cheap source of protein for animal feeds, for example, soybean products, such as textured vegetable protein, are ingredients in many meat and dairy substitutes. The beans contain significant amounts of acid, dietary minerals. Soy vegetable oil, used in food and industrial applications, is product of processing the soybean crop. Traditional non-fermented food uses of soybeans include soy milk from which tofu and tofu skin are made, fermented soy foods include soy sauce, fermented bean paste, natto and tempeh. The main countries growing soybeans are the United States, Brazil, the English words soy and soya are ultimately derived from the Japanese pronunciation of shōyu, the Sino-Japanese word for soy sauce, by way of the Dutch adaptation of the same word, soja. The genus Glycine Willd. is divided two subgenera, Glycine and Soja. Includes the cultivated soybean, Glycine max Merr. and the wild soybean, Glycine soja is the wild ancestor of Glycine max, and grows wild in China, Japan, Korea and Russia. The subgenus Glycine consists of at least 25 wild perennial species, for example, Glycine canescens F. J. Herm. and G. tomentella Hayata, perennial soybean originated in Africa and is now a widespread pasture crop in the tropics. Like some other crops of long domestication, the relationship of the soybean to wild-growing species can no longer be traced with any degree of certainty. It is a variety with a very large number of cultivars. Like most plants, soybeans grow in distinct morphological stages as they develop from seeds into fully mature plants, the first stage of growth is germination, a process that first becomes apparent as a seeds radicle emerges. This is the first stage of growth and occurs within the first 48 hours under ideal growing conditions. The first photosynthetic structures, the cotyledons, develop from the hypocotyl and these cotyledons both act as leaves and as a source of nutrients for the immature plant, providing the seedling nutrition for its first 7 to 10 days. The first true leaves develop as a pair of single blades, subsequent to this first pair, mature nodes form compound leaves with three blades. Mature trifoliolate leaves, having three to four leaflets per leaf, are often between 6–15 cm long and 2–7 cm broad, under ideal conditions, stem growth continues, producing new nodes every four days. Before flowering, roots can grow 1.9 cm per day, if rhizobia are present, root nodulation begins by the time the third node appears
4.
Okazaki, Aichi
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Okazaki is a city located in Aichi Prefecture, Japan. As of August 1, the city had an population of 384,056. The total area was 387.20 km2, Okazaki is located in the coastal plains of southeastern Aichi Prefecture. The ground rises to undulating hills in the former Nukata area to the northeast, about 60 percent of the city area is forested and remains sparsely populated. Okazaki is about 250 miles away from Tokyo, to the southwest, Aichi Prefecture Toyokawa Shinshiro Toyota Nishio Kōta Anjō Gamagōri The area around present-day Okazaki has been inhabited for many thousands of years. Archaeologists have found remains from the Japanese Paleolithic period, numerous remains from the Jomon period, and especially from the Yayoi and Kofun periods have also been found, including many kofun burial mounds. During the Sengoku period, the area was controlled by the Matsudaira clan, a branch of which rose to prominence as the Tokugawa clan. During this time, Okazaki Domain, a feudal han was established to rule the area around Okazaki. Several smaller domains were located within the present-day city limits, including Fukozu, Okudono Domain. The town prospered as a post station on the Tōkaidō connecting Edo with Kyoto, following the Meiji Restoration, the modern town of Okazaki was established on October 1,1889 within Nukata District of Aichi Prefecture. On October 1,1914, Okazaki annexed neighboring Hirohata Town, Okazaki was proclaimed a city on July 1,1916. The city suffered damage in both the 1944 Tōnankai earthquake and the 1945 Mikawa earthquake, during World War II, the July 19,1945 Bombing of Okazaki killed over 200 people and destroyed most of the city center. Although Okazaki was the location of an Imperial Japanese Navy air field, in 1955, through a series of mergers and consolidations, the area of Okazaki expanded considerably. The former towns of Iwazu, Fukuoka, and Yahagi, the 1959 Isewan Typhoon caused considerable damage, and killed 27 residents. On October 15,1962, Okazaki annexed the town of Mutsumi. Okazaki was proclaimed a city on April 1,2003 with increased autonomy from the prefectural government. On January 1,2006, the town of Nukata was merged into Okazaki, as of May 1,2006, the city government estimated the population at 368,201. The city is relatively young, with 139,233 households, the population comprises 185,651 males and 182,550 females, reflecting the number of young men who move to Okazaki to work in the manufacturing sector
5.
Sugar
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Sugar is the generic name for sweet, soluble carbohydrates, many of which are used in food. There are various types of derived from different sources. Simple sugars are called monosaccharides and include glucose, fructose, the table sugar or granulated sugar most customarily used as food is sucrose, a disaccharide of glucose and fructose. Sugar is used in prepared foods and it is added to some foods, in the body, sucrose is hydrolysed into the simple sugars fructose and glucose. Other disaccharides include maltose from malted grain, and lactose from milk, longer chains of sugars are called oligosaccharides or polysaccharides. Some other chemical substances, such as glycerol may also have a sweet taste, low-calorie food substitutes for sugar, described as artificial sweeteners, include aspartame and sucralose, a chlorinated derivative of sucrose. Sugars are found in the tissues of most plants and are present in sufficient concentrations for efficient commercial extraction in sugarcane, the world production of sugar in 2011 was about 168 million tonnes. The average person consumes about 24 kilograms of sugar each year, equivalent to over 260 food calories per person, since the latter part of the twentieth century, it has been questioned whether a diet high in sugars, especially refined sugars, is good for human health. Sugar has been linked to obesity, and suspected of, or fully implicated as a cause in the occurrence of diabetes, cardiovascular disease, dementia, macular degeneration, the etymology reflects the spread of the commodity. The English word sugar ultimately originates from the Sanskrit शर्करा, via Arabic سكر as granular or candied sugar, the contemporary Italian word is zucchero, whereas the Spanish and Portuguese words, azúcar and açúcar, respectively, have kept a trace of the Arabic definite article. The Old French word is zuchre and the contemporary French, sucre, the earliest Greek word attested is σάκχαρις. The English word jaggery, a brown sugar made from date palm sap or sugarcane juice, has a similar etymological origin – Portuguese jagara from the Sanskrit शर्करा. Sugar has been produced in the Indian subcontinent since ancient times and it was not plentiful or cheap in early times and honey was more often used for sweetening in most parts of the world. Originally, people chewed raw sugarcane to extract its sweetness, sugarcane was a native of tropical South Asia and Southeast Asia. Different species seem to have originated from different locations with Saccharum barberi originating in India and S. edule, one of the earliest historical references to sugarcane is in Chinese manuscripts dating back to 8th century BC that state that the use of sugarcane originated in India. Sugar was found in Europe by the 1st century AD, but only as an imported medicine and it is a kind of honey found in cane, white as gum, and it crunches between the teeth. It comes in lumps the size of a hazelnut, sugar is used only for medical purposes. Sugar remained relatively unimportant until the Indians discovered methods of turning sugarcane juice into granulated crystals that were easier to store, crystallized sugar was discovered by the time of the Imperial Guptas, around the 5th century AD
6.
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
7.
Manganese
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Manganese is a chemical element with symbol Mn and atomic number 25. It is not found as an element in nature, it is often found in minerals in combination with iron. Manganese is a metal with important industrial metal alloy uses, particularly in stainless steels, by the mid-18th century, Swedish chemist Carl Wilhelm Scheele had used pyrolusite to produce chlorine. Scheele and others were aware that pyrolusite contained a new element, johan Gottlieb Gahn was the first to isolate an impure sample of manganese metal in 1774, which he did by reducing the dioxide with carbon. Manganese phosphating is used for rust and corrosion prevention on steel, ionized manganese is used industrially as pigments of various colors, which depend on the oxidation state of the ions. The permanganates of alkali and alkaline earth metals are powerful oxidizers, Manganese dioxide is used as the cathode material in zinc-carbon and alkaline batteries. In biology, manganese ions function as cofactors for a variety of enzymes with many functions. Manganese enzymes are essential in detoxification of superoxide free radicals in organisms that must deal with elemental oxygen. Manganese also functions in the complex of photosynthetic plants. The element is a trace mineral for all known living organisms but is a neurotoxin. In larger amounts, and apparently with far greater effectiveness through inhalation, Manganese is a silvery-gray metal that resembles iron. It is hard and very brittle, difficult to fuse, Manganese metal and its common ions are paramagnetic. Manganese tarnishes slowly in air and oxidizes like iron in water containing dissolved oxygen, naturally occurring manganese is composed of one stable isotope, 55Mn. Eighteen radioisotopes have been isolated and described, the most stable being 53Mn with a half-life of 3.7 million years, 54Mn with a half-life of 312.3 days, and 52Mn with a half-life of 5.591 days. All of the radioactive isotopes have half-lives of less than three hours, and the majority of less than one minute. Manganese also has three meta states, Manganese is part of the iron group of elements, which are thought to be synthesized in large stars shortly before the supernova explosion. 53Mn decays to 53Cr with a half-life of 3.7 million years, because of its relatively short half-life, 53Mn is relatively rare, produced by cosmic rays impact on iron. Manganese isotopic contents are combined with chromium isotopic contents and have found application in isotope geology
8.
Zinc
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Zinc is a chemical element with the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table, in some respects zinc is chemically similar to magnesium, both elements exhibit only one normal oxidation state, and the Zn2+ and Mg2+ ions are of similar size. Zinc is the 24th most abundant element in Earths crust and has five stable isotopes, the most common zinc ore is sphalerite, a zinc sulfide mineral. The largest workable lodes are in Australia, Asia, and the United States, Zinc is refined by froth flotation of the ore, roasting, and final extraction using electricity. Zinc metal was not produced on a large scale until the 12th century in India and was unknown to Europe until the end of the 16th century, the mines of Rajasthan have given definite evidence of zinc production going back to the 6th century BC. To date, the oldest evidence of pure zinc comes from Zawar, in Rajasthan, alchemists burned zinc in air to form what they called philosophers wool or white snow. The element was named by the alchemist Paracelsus after the German word Zinke. German chemist Andreas Sigismund Marggraf is credited with discovering pure metallic zinc in 1746, work by Luigi Galvani and Alessandro Volta uncovered the electrochemical properties of zinc by 1800. Corrosion-resistant zinc plating of iron is the application for zinc. Other applications are in batteries, small non-structural castings. A variety of compounds are commonly used, such as zinc carbonate and zinc gluconate, zinc chloride, zinc pyrithione, zinc sulfide. Zinc is an essential mineral perceived by the public today as being of exceptional biologic and public health importance, Zinc deficiency affects about two billion people in the developing world and is associated with many diseases. In children, deficiency causes growth retardation, delayed sexual maturation, infection susceptibility, enzymes with a zinc atom in the reactive center are widespread in biochemistry, such as alcohol dehydrogenase in humans. Consumption of excess zinc can cause ataxia, lethargy and copper deficiency, Zinc is a bluish-white, lustrous, diamagnetic metal, though most common commercial grades of the metal have a dull finish.6 pm. The metal is hard and brittle at most temperatures but becomes malleable between 100 and 150 °C, above 210 °C, the metal becomes brittle again and can be pulverized by beating. Zinc is a conductor of electricity. For a metal, zinc has relatively low melting and boiling points, the melting point is the lowest of all the transition metals aside from mercury and cadmium. Many alloys contain zinc, including brass, Other metals long known to form binary alloys with zinc are aluminium, antimony, bismuth, gold, iron, lead, mercury, silver, tin, magnesium, cobalt, nickel, tellurium, and sodium
9.
Kilogram
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The kilogram or kilogramme is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype of the Kilogram. The avoirdupois pound, used in both the imperial and US customary systems, is defined as exactly 0.45359237 kg, making one kilogram approximately equal to 2.2046 avoirdupois pounds. Other traditional units of weight and mass around the world are also defined in terms of the kilogram, the gram, 1/1000 of a kilogram, was provisionally defined in 1795 as the mass of one cubic centimeter of water at the melting point of ice. The final kilogram, manufactured as a prototype in 1799 and from which the IPK was derived in 1875, had an equal to the mass of 1 dm3 of water at its maximum density. The kilogram is the only SI base unit with an SI prefix as part of its name and it is also the only SI unit that is still directly defined by an artifact rather than a fundamental physical property that can be reproduced in different laboratories. Three other base units and 17 derived units in the SI system are defined relative to the kilogram, only 8 other units do not require the kilogram in their definition, temperature, time and frequency, length, and angle. At its 2011 meeting, the CGPM agreed in principle that the kilogram should be redefined in terms of the Planck constant, the decision was originally deferred until 2014, in 2014 it was deferred again until the next meeting. There are currently several different proposals for the redefinition, these are described in the Proposed Future Definitions section below, the International Prototype Kilogram is rarely used or handled. In the decree of 1795, the term gramme thus replaced gravet, the French spelling was adopted in the United Kingdom when the word was used for the first time in English in 1797, with the spelling kilogram being adopted in the United States. In the United Kingdom both spellings are used, with kilogram having become by far the more common, UK law regulating the units to be used when trading by weight or measure does not prevent the use of either spelling. In the 19th century the French word kilo, a shortening of kilogramme, was imported into the English language where it has used to mean both kilogram and kilometer. In 1935 this was adopted by the IEC as the Giorgi system, now known as MKS system. In 1948 the CGPM commissioned the CIPM to make recommendations for a practical system of units of measurement. This led to the launch of SI in 1960 and the subsequent publication of the SI Brochure, the kilogram is a unit of mass, a property which corresponds to the common perception of how heavy an object is. Mass is a property, that is, it is related to the tendency of an object at rest to remain at rest, or if in motion to remain in motion at a constant velocity. Accordingly, for astronauts in microgravity, no effort is required to hold objects off the cabin floor, they are weightless. However, since objects in microgravity still retain their mass and inertia, the ratio of the force of gravity on the two objects, measured by the scale, is equal to the ratio of their masses. On April 7,1795, the gram was decreed in France to be the weight of a volume of pure water equal to the cube of the hundredth part of the metre
10.
Vitamin B12
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Vitamin B12, also called cobalamin, is a water-soluble vitamin that has a key role in the normal functioning of the brain and nervous system, and the formation of red blood cells. It is one of eight B vitamins and it is involved in the metabolism of every cell of the human body, especially affecting DNA synthesis, fatty acid and amino acid metabolism. No fungi, plants, or animals are capable of producing vitamin B12, only bacteria and archaea have the enzymes needed for its synthesis. Some substantial sources of B12 include animal products, fortified food products, vitamin B12 consists of a class of chemically related compounds, all of which show pharmacological activity. It contains the rare element cobalt positioned in the center of a planar tetra-pyrrole ring called a corrin ring. The vitamer is produced by bacteria as hydroxocobalamin, but conversion between different forms of the vitamin occurs in the body after consumption, because intrinsic factor is crucial for the normal absorption of B12, its lack in the presence of pernicious anemia causes a vitamin B12 deficiency. Many other subtler kinds of vitamin B12 deficiency and their biochemical effects have since been elucidated, due to impairment of vitamin B12 absorption during aging, people over age 60 are at risk of deficiency. The Food and Nutrition Board of the U. S, institute of Medicine updated Estimated Average Requirements and Recommended Dietary Allowances for vitamin B12 in 1998. The current EAR for vitamin B12 for women and men ages 14 and up is 2.0 μg/day, RDAs are higher than EARs so as to identify amounts that will cover people with higher than average requirements. RDA for pregnancy equals 2.6 μg/day, RDA for lactation equals 2.8 μg/day. For infants up to 12 months the Adequate Intake is 0. 4-0.5 μg/day. collectively the EARs, RDAs and ULs are referred to as Dietary Reference Intakes. As for safety, the IOM sets Tolerable Upper Intake Levels for vitamins, in the case of vitamin B12 there is no UL, as there is no human data for adverse effects from high doses. The European Food Safety Authority reviewed the same safety question and also reached the conclusion there was not sufficient evidence to set a UL for vitamin B12. For U. S. food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value. For vitamin B12 labeling purposes 100% of the Daily Value was 6.0 μg, a table of the pre-change adult Daily Values is provided at Reference Daily Intake. Food and supplement companies have until July 2018 to comply with the change, vitamin B12 deficiency can potentially cause severe and irreversible damage, especially to the brain and nervous system. Vitamin B12 deficiency can cause symptoms of mania and psychosis. Vitamin B12 deficiency is most commonly caused by low intakes, but can result from malabsorption, certain intestinal disorders, low presence of binding proteins
11.
Human iron metabolism
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Human iron metabolism is the set of chemical reactions maintaining human homeostasis of iron at both the systemic and cellular level. The control of this necessary but potentially toxic metal is an important part of many aspects of human health, hematologists have been especially interested in systemic iron metabolism because iron is essential for red blood cells, where most of the human bodys iron is contained. Understanding iron metabolism is also important for understanding diseases of iron overload, such as hereditary hemochromatosis, iron is an essential bioelement for most forms of life, from bacteria to mammals. Its importance lies in its ability to mediate electron transfer, in the ferrous state, iron acts as an electron donor, while in the ferric state it acts as an acceptor. Thus, iron plays a role in the catalysis of enzymatic reactions that involve electron transfer. Proteins can contain iron as part of different cofactors, such as clusters and heme groups. Human cells require iron in order to obtain energy as ATP from a process known as cellular respiration. Iron is present in the clusters and heme groups of the electron transport chain proteins that generate a proton gradient that allows ATP synthase to synthesize ATP. Heme groups are part of hemoglobin, a found in red blood cells that serves to transport oxygen from the lungs to the tissues. Heme groups are present in myoglobin to store and diffuse oxygen in muscle cells. The human body needs iron for oxygen transport, oxygen is required for the functioning and survival of nearly all cell types. Oxygen is transported from the lungs to the rest of the bound to the heme group of hemoglobin in erythrocytes. In muscles cells, iron binds myoglobin, which regulates its release and its ability to donate and accept electrons means that it can catalyze the conversion of hydrogen peroxide into free radicals. Free radicals can cause damage to a variety of cellular structures. Iron bound to proteins or cofactors such as heme is safe, also, there are virtually no truly free iron ions in the cell, since they readily form complexes with organic molecules. However, some of the iron is bound to low-affinity complexes. Iron in such complexes can cause damage as described above, to prevent that kind of damage, all life forms that use iron bind the iron atoms to proteins. This binding allows cells to benefit from iron while also limiting its ability to do harm, in mammalian cells, intracellular labile iron concentrations are typically smaller than 1 micromolar, less than 5 percent of total cellular iron
12.
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
