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Ergastic Substance
Ergastic substances are non-protoplasmic materials found in cells. The living protoplasm of a cell is sometimes called the bioplasm and distinct from the ergastic substances of the cell. The latter are usually organic or inorganic substances that are products of metabolism, and include crystals, oil drops, gums, tannins, resins and other compounds that can aid the organism in defense, maintenance of cellular structure, or just substance storage. Ergastic substances may appear in the protoplasm, in vacuoles, or in the cell wall. Carbohydrates Reserve carbohydrate of plants are the derivatives of the end products of photosynthesis. Cellulose and starch are the main ergastic substances of plant cells. Cellulose is the chief component of the cell wall, and starch occurs as a reserve material in the protoplasm. Starch, as starch grains, arise almost exclusively in plastids, especially leucoplasts and amyloplasts. Proteins Although proteins are the main component of living protoplasm, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoplasmic
Protoplasm (; ) is the living part of a cell that is surrounded by a plasma membrane. It is a mixture of small molecules such as ions, monosaccharides, amino acid, and macromolecules such as proteins, polysaccharides, lipids, etc. In some definitions, it is a general term for the cytoplasm (e.g., Mohl, 1846), but for others, it also includes the nucleoplasm (e.g., Strasburger, 1882). For Sharp (1921), "According to the older usage the extra-nuclear portion of the protoplast 'the entire cell, excluding the cell wall''was called "protoplasm," but the nucleus also is composed of protoplasm, or living substance in its broader sense. The current consensus is to avoid this ambiguity by employing Strasburger's '(1882)''terms cytoplasm Albert_von_Kölliker.html"_;"title="'coined_by_Albert_von_Kölliker">Kölliker_(1863),_originally_as_synonym_for_protoplasm''and_nucleoplasm_([''term_coined_by_Edouard_Van_Beneden.html" ;"title="Albert von Kölliker">Kölliker (1863), originally as synon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipid
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. Lipids have applications in the cosmetic and food industries, and in nanotechnology. Lipids may be broadly defined as hydrophobic or amphiphilic small molecules; the amphiphilic nature of some lipids allows them to form structures such as vesicles, multilamellar/unilamellar liposomes, or membranes in an aqueous environment. Biological lipids originate entirely or in part from two distinct types of biochemical subunits or "building-blocks": ketoacyl and isoprene groups. Using this approach, lipids may be divided into eight categories: fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, saccharolipids, and polyketides (derived from condensati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Druse (botany)
A druse is a group of crystals of calcium oxalate, silicates, or carbonates present in plants, and are thought to be a defense against herbivory due to their toxicity. Calcium oxalate (Ca(COO)2, CaOx) crystals are found in algae, angiosperms and gymnosperms in a total of more than 215 families. These plants accumulate oxalate in the range of 3–80% (w/w) of their dry weight through a biomineralization process in a variety of shapes. ''Araceae'' have numerous druses, multi-crystal druses and needle-shaped raphide crystals of CaOx present in the tissue. Druses are also found in leaves and bud scales of ''Prunus'', ''Rosa'', ''Allium'', ''Vitis'', ''Morus'' and ''Phaseolus''. Formation A number of biochemical pathways for calcium oxalate biomineralization in plants have been proposed. Among these are the cleavage of isocitrate, the hydrolysis of oxaloacetate, glycolate/glyoxylate oxidation, and/or oxidative cleavage of L-ascorbic acid. The cleavage of ascorbic acid appears to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taro
Taro () (''Colocasia esculenta)'' is a root vegetable. It is the most widely cultivated species of several plants in the family Araceae that are used as vegetables for their corms, leaves, and petioles. Taro corms are a food staple in African, Oceanic, and South Asian cultures (similar to yams). Taro is believed to be one of the earliest cultivated plants. Names and etymology The English term ''taro'' was borrowed from the Māori language when Captain Cook first observed ''Colocasia'' plantations there in 1769. The form ''taro'' or ''talo'' is widespread among Polynesian languages:*''talo'': taro (''Colocasia esculenta'') – entry in the ''Polynesian Lexicon Project Online'' (Pollex). in Tahitian; in < ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dieffenbachia
''Dieffenbachia'' , commonly known as dumb cane or leopard lily, is a genus of tropical flowering plants in the family Araceae. It is native to the New World Tropics from Mexico and the West Indies south to Argentina. Some species are widely cultivated as ornamental plants, especially as houseplants, and have become naturalized on a few tropical islands. ''Dieffenbachia'' is a perennial herbaceous plant with straight stem, simple and alternate leaves containing white spots and flecks, making it attractive as indoor foliage. Species in this genus are popular as houseplants because of their tolerance of shade. The English names, dumb cane and mother-in-law's tongue (also used for ''Sansevieria'' species) refer to the poisoning effect of raphides, which can cause temporary inability to speak. ''Dieffenbachia'' was named by Heinrich Wilhelm Schott, director of the Botanical Gardens in Vienna, to honor his head gardener Joseph Dieffenbach (1796–1863). Species The World Checklist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raphides
Raphides (pronounced /ˈræfɪˌdiz/, singular raphide /ˈreɪfʌɪd/ or raphis) are needle-shaped crystals of calcium oxalate monohydrate (prismatic monoclinic crystals) or calcium carbonate as aragonite ( dipyramidal orthorhombic crystals), found in more than 200 families of plants. Both ends are needle-like, but raphides tend to be blunt at one end and sharp at the other. Calcium oxalate in plants Many plants accumulate calcium oxalate crystals in response to surplus calcium, which is found throughout the natural environment. The crystals are produced in a variety of shapes. The crystal morphology depends on the taxonomic group of the plant. In one study of over 100 species, it was found that calcium oxalate accounted for 6.3% of plant dry weight. Crystal morphology and the distribution of raphides (in roots or leaves or tubers etc.) is similar in some taxa but different in others leaving possible opportunities for plant key characteristics and systematic identification; m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and most abundant families of materials, existing as a compound of several minerals and as a synthetic product. Notable examples include fused quartz, fumed silica, silica gel, opal and aerogels. It is used in structural materials, microelectronics (as an Insulator (electricity), electrical insulator), and as components in the food and pharmaceutical industries. Structure In the majority of silicates, the silicon atom shows tetrahedral coordination geometry, tetrahedral coordination, with four oxygen atoms surrounding a central Si atomsee 3-D Unit Cell. Thus, SiO2 forms 3-dimensional network solids in which each silicon atom is covalently bonded in a tetrahedral manner to 4 oxygen atoms. In contrast, CO2 is a linear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name derives from Latin ''calx'' "lime", which was obtained from heating limestone. Some calcium compounds were known to the ancients, though their chemistry was unknown until the seventeenth century. Pure calcium was isolated in 1808 via electrolysis of its oxide by Humphry Davy, who named the element. Calcium compounds are widely used in many industries: in foods and pharma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Minerals'; p. 1. In the series ''Geology: Landforms, Minerals, and Rocks''. Rosen Publishing Group. The geological definition of mineral normally excludes compounds that occur only in living organisms. However, some minerals are often biogenic (such as calcite) or are organic compounds in the sense of chemistry (such as mellite). Moreover, living organisms often synthesize inorganic minerals (such as hydroxylapatite) that also occur in rocks. The concept of mineral is distinct from rock, which is any bulk solid geologic material that is relatively homogeneous at a large enough scale. A rock may consist of one type of mineral, or may be an aggregate of two or more different types of minerals, spacially segregated into distinct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cutin
Cutin is one of two waxy polymers that are the main components of the plant cuticle, which covers all aerial surfaces of plants. It is an insoluble substance with waterproof quality. Cutin also harbors cuticular waxes, which assist in cuticle structure. The other major cuticle polymer is cutan, which is much more readily preserved in the fossil record. Cutin consists of omega hydroxy acids and their derivatives, which are interlinked via ester bonds, forming a polyester polymer of indeterminate size. There are two major monomer families of cutin, the C16 and C18 families. The C16 family consists mainly of 16-hydroxy palmitic acid and 9,16- or 10,16-dihydroxypalmitic acid. The C18 family consists mainly of 18-hydroxy oleic acid, 9,10-epoxy-18-hydroxy stearic acid Stearic acid ( , ) is a saturated fatty acid with an 18-carbon chain. The IUPAC name is octadecanoic acid. It is a waxy solid and its chemical formula is C17H35CO2H. Its name comes from the Greek word στέαρ "''st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suberin
Suberin, cutin and lignins are complex, higher plant epidermis and periderm cell-wall macromolecules, forming a protective barrier. Suberin, a complex polyester biopolymer, is lipophilic, and composed of long chain fatty acids called suberin acids, and glycerol. Suberins and lignins are considered covalently linked to lipids and carbohydrates, respectively, and lignin is covalently linked to suberin, and to a lesser extent, to cutin. Suberin is a major constituent of cork, and is named after the cork oak, ''Quercus suber''. Its main function is as a barrier to movement of water and solutes. Anatomy and physiology Suberin is highly hydrophobic and a somewhat 'rubbery' material. In roots, suberin is deposited in the radial and transverse/tangential cell walls of the endodermal cells. This structure, known as the Casparian strip or Casparian band, functions to prevent water and nutrients taken up by the root from entering the stele through the apoplast. Instead, water must bypass th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gluten
Gluten is a structural protein naturally found in certain cereal grains. Although "gluten" often only refers to wheat proteins, in medical literature it refers to the combination of prolamin and glutelin proteins naturally occurring in all grains that have been proved capable of triggering celiac disease. These include any species of wheat (such as common wheat, durum, spelt, khorasan, emmer and einkorn), barley, rye and some oat cultivars, as well as any cross hybrids of these grains (such as triticale). Gluten makes up 75–85% of the total protein in bread wheat. Glutens, especially Triticeae glutens, have unique viscoelastic and adhesive properties, which give dough its elasticity, helping it rise and keep its shape and often leaving the final product with a chewy texture. These properties, and its relatively low cost, make gluten valuable to both food and non-food industries. Wheat gluten is composed of mainly two types of proteins: the glutenins and the gliadins, which i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
