1.
Fungus
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A fungus is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from the other eukaryotic life kingdoms of plants, a characteristic that places fungi in a different kingdom from plants, bacteria and some protists, is chitin in their cell walls. Similar to animals, fungi are heterotrophs, they acquire their food by absorbing dissolved molecules, growth is their means of mobility, except for spores, which may travel through the air or water. Fungi are the principal decomposers in ecological systems and this fungal group is distinct from the structurally similar myxomycetes and oomycetes. The discipline of biology devoted to the study of fungi is known as mycology, in the past, mycology was regarded as a branch of botany, although it is now known fungi are genetically more closely related to animals than to plants. Abundant worldwide, most fungi are inconspicuous because of the size of their structures. Fungi include symbionts of plants, animals, or other fungi and they may become noticeable when fruiting, either as mushrooms or as molds. Fungi perform a role in the decomposition of organic matter and have fundamental roles in nutrient cycling. Since the 1940s, fungi have been used for the production of antibiotics, Fungi are also used as biological pesticides to control weeds, plant diseases and insect pests. Many species produce bioactive compounds called mycotoxins, such as alkaloids and polyketides, the fruiting structures of a few species contain psychotropic compounds and are consumed recreationally or in traditional spiritual ceremonies. Fungi can break down manufactured materials and buildings, and become significant pathogens of humans, losses of crops due to fungal diseases or food spoilage can have a large impact on human food supplies and local economies. The fungus kingdom encompasses a diversity of taxa with varied ecologies, life cycle strategies. However, little is known of the biodiversity of Kingdom Fungi. Advances in molecular genetics have opened the way for DNA analysis to be incorporated into taxonomy, phylogenetic studies published in the last decade have helped reshape the classification within Kingdom Fungi, which is divided into one subkingdom, seven phyla, and ten subphyla. The English word fungus is directly adopted from the Latin fungus, used in the writings of Horace, a group of all the fungi present in a particular area or geographic region is known as mycobiota, e. g. the mycobiota of Ireland. Like plants, fungi grow in soil and, in the case of mushrooms, form conspicuous fruit bodies. The fungi are now considered a kingdom, distinct from both plants and animals, from which they appear to have diverged around one billion years ago. Fungi have membrane-bound cytoplasmic organelles such as mitochondria, sterol-containing membranes and they have a characteristic range of soluble carbohydrates and storage compounds, including sugar alcohols, disaccharides, and polysaccharides
2.
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
3.
Protozoa
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In 21st-century systems of biological classification, the Protozoa are defined as a diverse group of unicellular eukaryotic organisms. Historically, protozoa were defined as single-celled animals or organisms with animal-like behaviors, such as motility, the group was regarded as the zoological counterpart to the protophyta, which were considered to be plant-like, as they are capable of photosynthesis. The terms protozoa and protozoans are now mostly used informally to designate single-celled, non-photosynthetic protists, such as the ciliates, amoebae and flagellates. The term Protozoa was introduced in 1818 for a taxonomic class, in several classification systems proposed by Thomas Cavalier-Smith and his collaborators since 1981, Protozoa is ranked as a kingdom. The seven-kingdom scheme proposed by Ruggiero et al. in 2015, places eight phyla under Protozoa, Euglenozoa, Amoebozoa, Metamonada, Choanozoa, Loukozoa, Percolozoa, Microsporidia and Sulcozoa. This kingdom does not form a clade, but an evolutionary grade or paraphyletic group, from which the fungi, for this reason, the terms protists, Protista or Protoctista are sometimes preferred for the high-level classification of eukaryotic microbes. In 2005, members of the Society of Protozoologists voted to change the name of organization to the International Society of Protistologists. The word protozoa was coined in 1818 by zoologist Georg August Goldfuss, as the Greek equivalent of the German Urthiere, meaning primitive, Goldfuss erected Protozoa as a class containing what he believed to be the simplest animals. Originally, the group included not only microbes, but also some lower animals, such as rotifers, corals, sponges, jellyfish, bryozoa. In 1848, in light of advancements in cell theory pioneered by Theodore Schwann and Matthias Schleiden, von Siebold redefined Protozoa to include only such unicellular forms, to the exclusion of all metazoa. At the same time, he raised the group to the level of a phylum containing two broad classes of microbes, Infusoria, and Rhizopoda. As a phylum under Animalia, the Protozoa were firmly rooted in the old two-kingdom classification of life, criticism of this system began in the latter half of the 19th century, with the realization that many organisms met the criteria for inclusion among both plants and animals. For example, the algae Euglena and Dinobryon have chloroplasts for photosynthesis, as an alternative, he proposed a new kingdom called Primigenum, consisting of both the protozoa and unicellular algae, which he combined together under the name Protoctista. In Hoggss conception, the animal and plant kingdoms were likened to two great pyramids blending at their bases in the Kingdom Primigenum, six years later, Ernst Haeckel also proposed a third kingdom of life, which he named Protista. Despite these proposals, Protozoa emerged as the taxonomic placement for heterotrophic microbes such as amoebae and ciliates. A variety of systems were proposed, and Kingdoms Protista and Protoctista became well established in biology texts. While many taxonomists have abandoned Protozoa as a group, Thomas Cavalier-Smith has retained it as a kingdom in the various classifications he has proposed. As of 2015, Cavalier-Smiths Protozoa excludes several major groups of organisms traditionally placed among the protozoa, including the ciliates, dinoflagellates, Protozoa, as traditionally defined, are mainly microscopic organisms, ranging in size from 10 to 52 micrometers
4.
Symbiosis
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Symbiosis is any type of a close and long-term biological interaction between two different species, be it mutualistic, commensalistic, or parasitic. In 1879, Heinrich Anton de Bary defined it as the living together of unlike organisms, Symbiosis can be obligatory, which means that one or both of the symbionts entirely depend on each other for survival, or facultative when they can generally live independently. When one organism lives on another such as mistletoe, it is called ectosymbiosis, or endosymbiosis when one partner lives inside the tissues of another, as in Symbiodinium in corals. In 1877, Albert Bernhard Frank used the term symbiosis which previously had used to depict people living together in community to describe the mutualistic relationship in lichens. In 1879, the German mycologist Heinrich Anton de Bary defined it as the living together of unlike organisms, symbiotic relationships can be obligate, meaning that one or both of the symbionts entirely depend on each other for survival. For example, in lichens, which consist of fungal and photosynthetic symbionts, the algal or cyanobacterial symbionts in lichens, such as Trentepohlia, can generally live independently, and their symbiosis is, therefore, facultative. Endosymbiosis is any relationship in which one symbiont lives within the tissues of the other, either within the cells or extracellularly. Mutualism or interspecies reciprocal altruism is a relationship between individuals of different species where both individuals benefit, in general, only lifelong interactions involving close physical and biochemical contact can properly be considered symbiotic. Mutualistic relationships may be either obligate for both species, obligate for one but facultative for the other, or facultative for both, a large percentage of herbivores have mutualistic gut flora to help them digest plant matter, which is more difficult to digest than animal prey. This gut flora is made up of cellulose-digesting protozoans or bacteria living in the herbivores intestines, coral reefs are the result of mutualisms between coral organisms and various types of algae which live inside them. Most land plants and land ecosystems rely on mutualisms between the plants, which fix carbon from the air, and mycorrhyzal fungi, which help in extracting water, an example of mutual symbiosis is the relationship between the ocellaris clownfish that dwell among the tentacles of Ritteri sea anemones. The territorial fish protects the anemone from anemone-eating fish, and in turn the stinging tentacles of the anemone protect the clownfish from its predators, a special mucus on the clownfish protects it from the stinging tentacles. A further example is the fish, which sometimes lives together with a shrimp. The shrimp digs and cleans up a burrow in the sand in which both the shrimp and the fish live. The shrimp is almost blind, leaving it vulnerable to predators when outside its burrow, in case of danger the goby fish touches the shrimp with its tail to warn it. When that happens both the shrimp and goby fish quickly retreat into the burrow, different species of gobies also exhibit mutualistic behavior through cleaning up ectoparasites in other fish. Another non-obligate symbiosis is known from encrusting bryozoans and hermit crabs, the bryozoan colony develops a cirumrotatory growth and offers the crab a helicospiral-tubular extension of its living chamber that initially was situated within a gastropod shell. A spectacular examples of mutualism is between the siboglinid tube worms and symbiotic bacteria that live at hydrothermal vents and cold seeps
5.
Termite
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Termites are eusocial insects that are classified at the taxonomic rank of infraorder Isoptera, or as epifamily Termitoidae within the cockroach order Blattodea. Termites were once classified in an order from cockroaches. However, the first termites emerged during the Permian or even the Carboniferous. About 3,106 species are described, with a few hundred more left to be described. Although these insects are called white ants, they are not ants. Like ants and some bees and wasps from the separate order Hymenoptera, all colonies have fertile males called kings and one or more fertile females called queens. Termites mostly feed on plant material and cellulose, generally in the form of wood, leaf litter, soil. Termites are major detritivores, particularly in the subtropical and tropical regions, Termites are among the most successful groups of insects on Earth, colonising most landmasses except for Antarctica. Their colonies range in size from a few hundred individuals to enormous societies with several million individuals, Termite queens have the longest lifespan of any insect in the world, with some queens reportedly living up to 30 to 50 years. Unlike ants, which undergo a metamorphosis, each individual termite goes through an incomplete metamorphosis that proceeds through egg, nymph. Colonies are described as superorganisms because the termites form part of a self-regulating entity, Termites are a delicacy in the diet of some human cultures and are used in many traditional medicines. Several hundred species are significant as pests that can cause serious damage to buildings, crops. Some species, such as the West Indian drywood termite, are regarded as invasive species, the infraorder name Isoptera is derived from the Greek words iso and ptera, which refers to the nearly equal size of the fore and hind wings. Termite derives from the Latin and Late Latin word termes, altered by the influence of Latin terere from the earlier word tarmes, Termite nests were commonly known as terminarium or termitaria. In early English, termites were known as wood ants or white ants, the modern term was first used in 1781. DNA analysis from 16S rRNA sequences has supported a hypothesis, originally suggested by Cleveland and colleagues in 1934 and this earlier conclusion had been based on the similarity of the symbiotic gut flagellates in the wood-eating cockroaches to those in certain species of termites regarded as living fossils. In the 1960s additional evidence supporting that hypothesis emerged when F. A. McKittrick noted similar morphological characteristics between some termites and Cryptocercus nymphs. These similarities have led some authors to propose that termites be reclassified as a family, the Termitidae, within the order Blattodea
6.
Coffee
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Coffee is a brewed drink prepared from roasted coffee beans, which are the seeds of berries from the Coffea plant. The genus Coffea is native to tropical Africa, and Madagascar, the two most commonly grown are the highly regarded arabica, and the less sophisticated but stronger and more hardy robusta. Once ripe, coffee berries are picked, processed, and dried, dried coffee seeds are roasted to varying degrees, depending on the desired flavor. Roasted beans are ground and brewed with boiling water to produce coffee as a beverage. Coffee is slightly acidic and can have an effect on humans because of its caffeine content. Coffee is one of the most popular drinks in the world and it can be prepared and presented in a variety of ways. It is usually served hot, although iced coffee is also served, the earliest credible evidence of coffee-drinking appears in the middle of the 15th century in the Sufi shrines of Yemen. It was here in Arabia that coffee seeds were first roasted and brewed in a way to how it is now prepared. Coffee seeds were first exported from East Africa to Yemen, as the coffea arabica plant is thought to have been indigenous to the former, yemeni traders took coffee back to their homeland and began to cultivate the seed. By the 16th century, it had reached Persia, Turkey, from there, it spread to Europe and the rest of the world. Coffee is an export commodity, it is the top agricultural export for numerous countries and is among the worlds largest legal agricultural exports. It is one of the most valuable commodities exported by developing countries, green coffee is one of the most traded agricultural commodities in the world. Consequently, the markets for fair trade coffee and organic coffee are expanding. The first reference to coffee in the English language is in the form chaona, dated to 1598 and understood to be a misprint of chaoua, equivalent, in the orthography of the time, to chaova. This term and coffee both derive from the Ottoman Turkish kahve, by way of the Italian caffè and it has also been proposed that the source may be the Proto-Central Semitic root q-h-h meaning dark. Alternatively, the word Khat, a plant widely used as stimulant in Yemen and Ethiopia before being supplanted by coffee has been suggested as a possible origin, the expression coffee break was first attested in 1952. The term coffee pot dates from 1705, other accounts attribute the discovery of coffee to Sheikh Omar. According to the ancient chronicle, Omar, who was known for his ability to cure the sick through prayer, was exiled from Mocha in Yemen to a desert cave near Ousab
7.
Coffee bean
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A coffee seed, commonly called coffee bean, is a seed of the coffee plant, and is the source for coffee. It is the pit inside the red or purple fruit often referred to as a cherry, just like ordinary cherries, the coffee fruit is also a so-called stone fruit. Even though the coffee beans are seeds, they are referred to as beans because of their resemblance to true beans, the fruits – coffee cherries or coffee berries – most commonly contain two stones with their flat sides together. A small percentage of cherries contain a seed, instead of the usual two. The peaberry occurs only between 10 and 15% of the time, and it is a common belief that they have more flavour than normal coffee beans. Like Brazil nuts and white rice, coffee beans consist mostly of endosperm, the two most economically important varieties of coffee plant are the Arabica and the Robusta, 75–80% of the coffee produced worldwide is Arabica and 20% is Robusta. Arabica beans consist of 0. 8–1. 4% caffeine and Robusta beans consist of 1. 7–4% caffeine, according to popular legend, the coffee plant was discovered in Ethiopia by a goatherd named Kaldi. Significant dates The first coffee plant was found in the mountains of Yemen, then by 1500, it was exported to the rest of the world through the port of Mokha in Yemen. Roasted beans first sold on retail market –1865 Important spray-drying techniques developed in 1950s Distribution South America is now responsible for about 45% of the worlds total coffee exports, most of this coffee is grown in Brazil. The United States imports more coffee than any other nation, the per capita consumption of coffee in the United States in 2011 was 4.24 kg, and the value of coffee imported exceeded $8 billion. As of 2015, Americans consumed approximately 400 million cups of coffee per day, Coffee plants grow within a defined area between the Tropics of Cancer and Capricorn, termed the bean belt or coffee belt. The Oxford English Dictionary suggests that the European languages generally appear to have gotten the name from Turkish kahveh, about 1600, another common theory is that the name derives from Kaffa Province, Ethiopia, where the species may have originated. The coffea tree averages from 5–10 m in height, as the tree gets older, it branches less and less and bears more leaves and fruits. Coffea plants are grown in several feet apart. Some farmers plant fruit trees around them or plant the coffee on the sides of hills, ideally, Arabica coffee beans are grown at temperatures between 15 and 24 °C and Robusta at 24–30 °C and receive between 15 and 30 cm of rainfall per year. Heavy rain is needed in the beginning of the season when the fruit is developing and this selective picking gives the growers reason to give their coffee a certain specification called operation cherry red. In rare circumstances, the Asian palm civet eats coffee berries and excretes the beans and these beans are called kopi luwak, and can be processed further into a rare and expensive coffee. Two methods are used to process coffee berries
8.
Biomass
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Biomass is an industry term for getting energy by burning wood, and other organic matter. It has become popular among power stations, which switch from coal to biomass to comply with the law. Biomass most often refers to plants or plant-based materials that are not used for food or feed, as an energy source, biomass can either be used directly via combustion to produce heat, or indirectly after converting it to various forms of biofuel. Conversion of biomass to biofuel can be achieved by different methods which are classified into, thermal, chemical. Historically, humans have harnessed biomass-derived energy since the time people began burning wood to make fire. Even today, biomass is the source of fuel for domestic use in many developing countries. Biomass is all biologically-produced matter based in carbon, hydrogen and oxygen, the estimated biomass production in the world is 104.9 petagrams of carbon per year, about half in the ocean and half on land. Wood remains the largest biomass energy source today, examples include forest residues, yard clippings, wood chips, wood energy is derived by using lignocellulosic biomass as fuel. Harvested wood may be used directly as a fuel or collected from waste streams to be processed into pellet fuel or other forms of fuels. The largest source of energy from wood is pulping liquor or black liquor, in the second sense, biomass includes plant or animal matter that can be converted into fibers or other industrial chemicals, including biofuels. Based on the source of biomass, biofuels are classified broadly into two major categories, first-generation biofuels are derived from sources such as sugarcane and corn starch. Sugars present in this biomass are fermented to produce bioethanol, a fuel which can be used directly in a fuel cell to produce electricity or serve as an additive to gasoline. However, utilizing food-based resources for production only aggravates the food shortage problem. Second-generation biofuels, on the hand, utilize non-food-based biomass sources such as agriculture. These biofuels mostly consist of lignocellulosic biomass, which is not edible and is a waste for many industries. Despite being the alternative, economical production of second-generation biofuel is not yet achieved due to technological issues. These issues arise due to chemical inertness and structural rigidity of lignocellulosic biomass. Plant energy is produced by crops grown for use as fuel that offer high biomass output per hectare with low input energy
9.
Biofuel
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Biofuels can be derived directly from plants, or indirectly from agricultural, commercial, domestic, and/or industrial wastes. Renewable biofuels generally involve contemporary carbon fixation, such as those that occur in plants or microalgae through the process of photosynthesis, other renewable biofuels are made through the use or conversion of biomass. This biomass can be converted to convenient energy-containing substances in three different ways, thermal conversion, chemical conversion, and biochemical conversion and this biomass conversion can result in fuel in solid, liquid, or gas form. This new biomass can also be used directly for biofuels, bioethanol is an alcohol made by fermentation, mostly from carbohydrates produced in sugar or starch crops such as corn, sugarcane, or sweet sorghum. Cellulosic biomass, derived from sources, such as trees and grasses, is also being developed as a feedstock for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form, bioethanol is widely used in the USA and in Brazil. Current plant design does not provide for converting the portion of plant raw materials to fuel components by fermentation. Biodiesel is produced from oils or fats using transesterification and is the most common biofuel in Europe, in 2010, worldwide biofuel production reached 105 billion liters, up 17% from 2009, and biofuels provided 2. 7% of the worlds fuels for road transport. Global ethanol fuel production reached 86 billion liters in 2010, with the United States and Brazil as the top producers. The worlds largest biodiesel producer is the European Union, accounting for 53% of all production in 2010. As of 2011, mandates for blending biofuels exist in 31 countries at the national level, the International Energy Agency has a goal for biofuels to meet more than a quarter of world demand for transportation fuels by 2050 to reduce dependence on petroleum and coal. The production of biofuels also led into an automotive industry. There are various social, economic, environmental and technical issues relating to production and use. Most transportation fuels are liquids, because vehicles usually require high energy density and this occurs naturally in liquids and solids. High energy density can also be provided by a combustion engine. The fuels that are easiest to burn cleanly are typically liquids, thus, liquids meet the requirements of being both energy-dense and clean-burning. In addition, liquids can be pumped, which means handling is easily mechanized, first-generation or conventional biofuels are made from sugar, starch, or vegetable oil. Biobutanol is often claimed to provide a replacement for gasoline
10.
Catalysis
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Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst. In most cases, reactions occur faster with a catalyst because they require less activation energy, furthermore, since they are not consumed in the catalyzed reaction, catalysts can continue to act repeatedly. Often only tiny amounts are required in principle, in the presence of a catalyst, less free energy is required to reach the transition state, but the total free energy from reactants to products does not change. A catalyst may participate in multiple chemical transformations, the effect of a catalyst may vary due to the presence of other substances known as inhibitors or poisons or promoters. Catalyzed reactions have an activation energy than the corresponding uncatalyzed reaction, resulting in a higher reaction rate at the same temperature. However, the mechanics of catalysis is complex. Usually, the catalyst participates in this slowest step, and rates are limited by amount of catalyst, in heterogeneous catalysis, the diffusion of reagents to the surface and diffusion of products from the surface can be rate determining. A nanomaterial-based catalyst is an example of a heterogeneous catalyst, analogous events associated with substrate binding and product dissociation apply to homogeneous catalysts. Although catalysts are not consumed by the reaction itself, they may be inhibited, deactivated, in heterogeneous catalysis, typical secondary processes include coking where the catalyst becomes covered by polymeric side products. Additionally, heterogeneous catalysts can dissolve into the solution in a system or sublimate in a solid–gas system. The production of most industrially important chemicals involves catalysis, similarly, most biochemically significant processes are catalysed. Research into catalysis is a field in applied science and involves many areas of chemistry, notably organometallic chemistry. Catalysis is relevant to aspects of environmental science, e. g. the catalytic converter in automobiles. Many transition metals and transition metal complexes are used in catalysis as well, Catalysts called enzymes are important in biology. A catalyst works by providing a reaction pathway to the reaction product. The rate of the reaction is increased as this route has a lower activation energy than the reaction route not mediated by the catalyst. The disproportionation of hydrogen peroxide creates water and oxygen, as shown below,2 H2O2 →2 H2O + O2 This reaction is preferable in the sense that the reaction products are more stable than the starting material, though the uncatalysed reaction is slow. In fact, the decomposition of hydrogen peroxide is so slow that hydrogen peroxide solutions are commercially available and this reaction is strongly affected by catalysts such as manganese dioxide, or the enzyme peroxidase in organisms
11.
Beta-glucan
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Various studies have examined the potential health effects of β-glucan. Oat fiber β-glucan at intake levels of at least 3 g per day can decrease the levels of saturated fats in the blood, some studies have suggested that cereal-derived β-glucan may also have immunomodulatory properties. Yeast- and medicinal mushroom-derived β-glucans have been investigated for their ability to modulate the immune system, β-glucans are further used in various nutraceutical and cosmetic products, as texturing agents, and as soluble fiber supplements, but can be problematic in the process of brewing. Cereal and fungal products have been used for centuries for medicinal and cosmetic purposes, however, β-glucans were first discovered in lichens, and shortly thereafter in barley. A particular interest in oat β-glucan arose after their cholesterol lowering effect was reported in 1984, in 1997, the FDA approved of a claim that intake of at least 3 g of β-glucan from oats per day decreased saturated fats and reduced the risk of heart disease. Although technically β-glucans are chains of D-glucose polysaccharides linked by glycosidic bonds. Cellulose is not typically considered a β-glucan, as it is insoluble, some β-glucan molecules have branching glucose side-chains attached to other positions on the main D-glucose chain, which branch off the β-glucan backbone. In addition, these side-chains can be attached to other types of molecules, like proteins, the most common forms of β-glucans are those comprising D-glucose units with β-1,3 links. Yeast and fungal β-glucans contain 1-6 side branches, while cereal β-glucans contain both β-1,3 and β-1,4 backbone bonds, the frequency, location, and length of the side-chains may play a role in immunomodulation. Differences in molecular weight, shape, and structure of β-glucans dictate the differences in biological activity, β-glucans form a natural component of the cell walls of bacteria, fungi, yeast, and cereals such as oat and barley. Each type of beta-glucan comprises a different molecular backbone, level of branching, one of the most common sources of βD-glucan for supplement use is derived from the cell wall of baker’s yeast. The βD-glucans from yeast are often insoluble, however, β-glucans are also extracted from the bran of some grains, such as oats and barley, and to a much lesser degree in rye and wheat. Other sources include some types of seaweed, and various species of mushrooms, such as reishi, Ganoderma applanatum, shiitake, Chaga, cereal β-glucans from oat, barley, wheat, and rye induce a variety of physiological effects that positively impact health. Barley and oat β-glucans have been studied for their effects on blood glucose regulation in test subjects with hypercholesterolemia, oats and barley differ in the ratio of trimer and tetramer 1-4 linkages. Barley has more 1-4 linkages with a degree of higher than 4. However, the majority of barley blocks remain trimers and tetramers, in oats, β-glucan is found mainly in the endosperm of the oat kernel, especially in the outer layers of that endosperm. β-D-Glucan forms part of the wall of certain medically important fungi. Mushroom beta-glucans are linked by 1,3 glycosidic bonds with 1,6 branches, an assay to detect its presence in blood is marketed as a means of diagnosing invasive fungal infection in patients
12.
Protein folding
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It is the physical process by which a polypeptide folds into its characteristic and functional three-dimensional structure from random coil. Each protein exists as a polypeptide or random coil when translated from a sequence of mRNA to a linear chain of amino acids. This polypeptide lacks any stable three-dimensional structure, as the polypeptide chain is being synthesized by the ribosome, the linear chain begins to fold into its three dimensional structure. Folding begins to occur even during translation of the polypeptide chain, amino acids interact with each other to produce a well-defined three-dimensional structure, the folded protein, known as the native state. The resulting three-dimensional structure is determined by the amino acid sequence or primary structure, the energy landscape describes the folding pathways in which the unfolded protein is able to assume its native state. Experiments beginning in the 1980s indicate the codon for an acid can also influence protein structure. The correct three-dimensional structure is essential to function, although parts of functional proteins may remain unfolded. Failure to fold into native structure generally produces inactive proteins, several neurodegenerative and other diseases are believed to result from the accumulation of amyloid fibrils formed by misfolded proteins. Many allergies are caused by folding of some proteins, because the immune system does not produce antibodies for certain protein structures. The primary structure of a protein, its linear amino-acid sequence, the amino acid composition is not as important as the sequence. The essential fact of folding, however, remains that the amino acid sequence of protein contains the information that specifies both the native structure and the pathway to attain that state. This is not to say that nearly identical amino acid sequences always fold similarly, conformations differ based on environmental factors as well, similar proteins fold differently based on where they are found. Formation of a structure is the first step in the folding process that a protein takes to assume its native structure. Formation of intramolecular hydrogen bonds provides another important contribution to protein stability, alpha helices are formed by hydrogen bonding of the backbone to form a spiral shape. The beta pleated sheet is a structure forms with the backbone bending over itself to form the hydrogen bonds. The hydrogen bonds are between the hydrogen and carbonyl carbon of the peptide bond. The alpha helices and beta pleated sheets can be amphipathic in nature, or contain a hydrophilic portion, secondary structure hierarchically gives way to tertiary structure formation. Tertiary structure of a protein involves a single chain, however
