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Chlorophyll C
Chlorophyll ''c'' refers to forms of chlorophyll found in certain marine algae, including the photosynthetic Chromista (e.g. diatoms and brown algae) and dinoflagellates. These pigments are characterized by their unusual chemical structure, with a porphyrin as opposed to the chlorin (which has a reduced ring D) as the core; they also do not have an isoprenoid tail. Both these features stand out from the other chlorophylls commonly found in algae and plants. It has a blue-green color and is an accessory pigment, particularly significant in its absorption of light in the 447–520 nm wavelength region. Like chlorophyll ''a'' and chlorophyll ''b'', it helps the organism gather light and passes a quanta of excitation energy through the light harvesting antennae to the photosynthetic reaction centre. Chlorophyll ''c'' can be further divided into chlorophyll ''c''1, chlorophyll ''c''2, and chlorophyll ''c''3, plus at least eight other more recently found subtypes. Chlorophyll ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorophyll
Chlorophyll is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words (, "pale green") and (, "leaf"). Chlorophyll allows plants to absorb energy from light. Those pigments are involved in oxygenic photosynthesis, as opposed to bacteriochlorophylls, related molecules found only in bacteria and involved in anoxygenic photosynthesis. Chlorophylls absorb light most strongly in the blue portion of the electromagnetic spectrum as well as the red portion. Conversely, it is a poor absorber of green and near-green portions of the spectrum. Hence chlorophyll-containing tissues appear green because green light, diffusively reflected by structures like cell walls, is less absorbed. Two types of chlorophyll exist in the photosystems of green plants: chlorophyll ''a'' and ''b''. History Chlorophyll was first isolated and named by Joseph Bienaimé Caventou and Pierre Joseph Pelletier in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosynthetic Reaction Centre
A photosynthetic reaction center is a complex of several proteins, biological pigments, and other co-factors that together execute the primary energy conversion reactions of photosynthesis. Molecular excitations, either originating directly from sunlight or transferred as excitation energy via light-harvesting antenna systems, give rise to electron transfer reactions along the path of a series of protein-bound co-factors. These co-factors are light-absorbing molecules (also named chromophores or pigments) such as chlorophyll and pheophytin, as well as quinones. The energy of the photon is used to excite an electron of a pigment. The Thermodynamic free energy, free energy created is then used, via a chain of nearby electron acceptors, for a transfer of hydrogen atoms (as protons and electrons) from H2O or hydrogen sulfide towards carbon dioxide, eventually producing glucose. These electron transfer steps ultimately result in the conversion of the energy of photons to chemical en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosynthetic Pigments
A photosynthetic pigment (accessory pigment; chloroplast pigment; antenna pigment) is a pigment that is present in chloroplasts or photosynthetic bacteria and captures the light energy necessary for photosynthesis. List of photosynthetic pigments (in order of increasing polarity): *Carotene: an orange pigment *Xanthophyll: a yellow pigment * Phaeophytin ''a'': + energy n the other side of the m ... when exposed to light. References {{reflist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porphyrins
Porphyrins ( ) are heterocyclic, macrocyclic, organic compounds, composed of four modified pyrrole subunits interconnected at their α carbon atoms via methine bridges (). In vertebrates, an essential member of the porphyrin group is heme, which is a component of hemoproteins, whose functions include carrying oxygen in the bloodstream. In plants, an essential porphyrin derivative is chlorophyll, which is involved in light harvesting and electron transfer in photosynthesis. The parent of porphyrins is porphine, a rare chemical compound of exclusively theoretical interest. Substituted porphines are called porphyrins. With a total of 26 π-electrons the porphyrin ring structure is a coordinated aromatic system. One result of the large conjugated system is that porphyrins absorb strongly in the visible region of the electromagnetic spectrum, i.e. they are deeply colored. The name "porphyrin" derives . Structure Porphyrin complexes consist of a square planar MN4 core. The periph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Divinyl Chlorophyllide A 8-vinyl-reductase
In enzymology, divinyl chlorophyllide ''a'' 8-vinyl-reductase () is an enzyme that catalyzes the chemical reaction :3,8-divinylprotochlorophyllide + NADPH + H+ \rightleftharpoons protochlorophyllide + NADP+ The three substrates of this enzyme are 3,8-divinylprotochlorophyllide, NADPH, and H+; its two products are protochlorophyllide and NADP+. This enzyme can also convert alternative substrates, for example 3,8-divinyl chlorophyllide ''a'' and in all cases reduces a single specific vinyl group to an ethyl group. This enzyme belongs to the family of oxidoreductases. The systematic name of this enzyme class is chlorophyllide-''a'' :NADP+ oxidoreductase. Other names in common use include 3,8-divinyl protochlorophyllide ''a'' 8-vinyl-reductase, -vinylhlorophyllide ''a'' reductase, and 4VCR. This enzyme is part of the biosynthetic pathway to chlorophyll Chlorophyll is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorophyllide
Chlorophyllide ''a'' and chlorophyllide ''b'' are the biosynthesis, biosynthetic precursors of chlorophyll a, chlorophyll ''a'' and chlorophyll b, chlorophyll ''b'' respectively. Their propionic acid groups are converted to phytol, phytyl esters by the enzyme chlorophyll synthase in the final step of the pathway. Thus the main interest in these chemical compounds has been in the study of chlorophyll biosynthesis in plants, algae and cyanobacteria. Chlorophyllide ''a'' is also an intermediate in the biosynthesis of bacteriochlorophylls. Structures Chlorophyllide ''a'', is a carboxylic acid (R=H). In chlorophyllide ''b'', the methyl group at position 13 (IUPAC nomenclature of organic chemistry, IUPAC numbering for chlorophyllide ''a'') and highlighted in the green box, is replaced with a aldehyde, formyl Functional group, group. Biosynthesis steps up to formation of protoporphyrin IX In the early steps of the biosynthesis, which starts from glutamic acid, a tetrapyrrole is created b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emiliania Huxleyi
''Gephyrocapsa huxleyi'', also called ''Emiliania huxleyi'', is the most abundant species of coccolithophore in modern oceans found in almost all ecosystems from the equator to sub-polar regions, and from nutrient rich upwelling zones to nutrient poor oligotrophic waters. It is one of thousands of different photosynthetic plankton that freely drift in the photic zone of the ocean, forming the basis of virtually all marine food webs. It is studied for the extensive blooms it forms in nutrient-depleted waters after the reformation of the summer thermocline. Like other coccolithophores, ''G. huxleyi'' is a single-celled phytoplankton covered with uniquely ornamented calcite disks called coccoliths. Individual coccoliths are abundant in marine sediments although complete coccospheres are more unusual. In the case of ''G. huxleyi'', not only the shell, but also the soft part of the organism may be recorded in sediments. It produces a group of chemical compounds that are very ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetone
Acetone (2-propanone or dimethyl ketone) is an organic compound with the chemical formula, formula . It is the simplest and smallest ketone (). It is a colorless, highly Volatile organic compound, volatile, and flammable liquid with a characteristic pungent odor. Acetone is miscibility, miscible with properties of water, water and serves as an important organic solvent in industry, home, and laboratory. About 6.7 million tonnes were produced worldwide in 2010, mainly for use as a solvent and for production of methyl methacrylate and bisphenol A, which are precursors to widely used plastics.Acetone World Petrochemicals report, January 2010Stylianos Sifniades, Alan B. Levy, "Acetone" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. It is a common building block in organic chemistry. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diethyl Ether
Diethyl ether, or simply ether, is an organic compound with the chemical formula , sometimes abbreviated as . It is a colourless, highly Volatility (chemistry), volatile, sweet-smelling ("ethereal odour"), extremely flammable liquid. It belongs to the ether class of organic compounds. It is a common solvent and was formerly used as a general anesthetic. Production Most diethyl ether is produced as a byproduct of the vapor-phase Hydration reaction, hydration of ethylene to make ethanol. This process uses solid-supported phosphoric acid Catalysis, catalysts and can be adjusted to make more ether if the need arises: Vapor-phase Dehydration reaction, dehydration of ethanol over some Aluminium oxide, alumina catalysts can give diethyl ether yields of up to 95%. : Diethyl ether can be prepared both in laboratories and on an industrial scale by the acid ether synthesis. Uses The dominant use of diethyl ether is as a solvent. One particular application is in the production of cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absorption Band
In spectroscopy, an absorption band is a range of wavelengths, frequency, frequencies or energies in the electromagnetic spectrum that are characteristic of a particular transition from initial to final state in a substance. According to quantum mechanics, atoms and molecules can only hold certain defined quantities of energy, or exist in specific Quantum state, states. When such quantum, quanta of electromagnetic radiation are emitted or absorbed by an atom or molecule, energy of the radiation changes the state of the atom or molecule from an Ground state, initial state to a Excited state, final state. Overview When electromagnetic radiation is absorbed by an atom or molecule, the energy of the radiation changes the state of the atom or molecule from an Ground state, initial state to a Excited state, final state. The number of states in a specific energy range is discrete for gaseous or diluted systems, with discrete energy levels. Condensed matter physics, Condensed systems, lik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorophyll B
} Chlorophyll ''b'' is a form of chlorophyll. Chlorophyll ''b'' helps in photosynthesis by absorbing light energy. It is more soluble than chlorophyll ''a'' in polar solvents because of its carbonyl group. Its color is green, and it primarily absorbs blue light. In land plants, the light-harvesting antennae around photosystem II contain the majority of chlorophyll ''b''. Hence, in shade-adapted chloroplasts, which have an increased ratio of photosystem II to photosystem I, there is a higher ratio of chlorophyll ''b'' to chlorophyll ''a''. This is adaptive, as increasing chlorophyll ''b'' increases the range of wavelengths absorbed by the shade chloroplasts. Biosynthesis The Chlorophyll ''b'' biosynthetic pathway utilizes a variety of enzymes. In most plants, chlorophyll is derived from glutamate and is synthesised along a branched pathway that is shared with heme and siroheme. The initial steps incorporate glutamic acid into 5-aminolevulinic acid (ALA); two molecules o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromista
Chromista is a proposed but polyphyletic obsolete Biology, biological Kingdom (biology), kingdom, refined from the Chromalveolata, consisting of single-celled and multicellular eukaryotic species that share similar features in their Photosynthesis, photosynthetic organelles (plastids). It includes all eukaryotes whose plastids contain chlorophyll c, chlorophyll ''c'' and are surrounded by four membranes. If the ancestor already possessed chloroplasts derived by Endosymbiont, endosymbiosis from red algae, all non-photosynthetic Chromista have secondarily lost the ability to photosynthesise. Its members might have arisen independently as separate evolutionary groups from the last eukaryotic common ancestor. Chromista as a taxon was created by the British biologist Thomas Cavalier-Smith in 1981 to distinguish the stramenopiles, haptophytes, and Cryptomonad, cryptophytes. According to Cavalier-Smith, the kingdom originally consisted mostly of photosynthetic eukaryotes (algae), but he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
