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Pentamer
A pentamer is an entity composed of five subunits. In chemistry, it applies to molecules made of five monomers. In biochemistry, it applies to macromolecules, particularly pentameric proteins, made of five protein sub-units. In microbiology, a pentamer is one of the proteins that compose the polyhedral protein shell that encloses the bacterial micro-compartments known as carboxysomes. In immunology, an MHC pentamer is a reagent used to detect antigen-specific CD8+ T cell T cells (also known as T lymphocytes) are an important part of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell ...s. See also * penta prefix * -mer suffix * Pentamerism * '' Pentamerous Metamorphosis'', an album by Global Communication * Pentamery (botany), having five parts in a distinct whorl of a plant structure * Pentamerous can also refer to animals, such as c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentameric Protein
A pentameric protein is a quaternary protein structure that consists of five protein subunits. Examples Ligand-gated ion channels Five sub-units come together to form a channel. Each channel consist of two alpha chain, one beta, one gamma and one delta chain. These five chains assemble together (along with certain receptors like protons or acetylcholine) forming the structure of the channel. A ligand-gated ion channel on the post-synaptic junction of the muscle end-plate is an example of such a channel. They are acetylcholine-operated ion channels, which means that acetylcholine brings about a conformational change. The channel allows the free movement of the cations like and when acetylcholine binds to its receptors. Viral capsids Many viral capsids are formed by hexameric and pentameric proteins. Such capsids are assigned a triangulation number (T-number) which describe relation between the number of pentagons and hexagons. Carboxysomes Protein enclosing bacterial orga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxysome
Carboxysomes are bacterial microcompartments (BMCs) consisting of polyhedral protein shells filled with the enzymes ribulose-1,5-bisphosphate carboxylase/oxygenase ( RuBisCO)—the predominant enzyme in carbon fixation and the rate limiting enzyme in the Calvin cycle—and carbonic anhydrase. Carboxysomes are thought to have evolved as a consequence of the increase in oxygen concentration in the ancient atmosphere; this is because oxygen is a competing substrate to carbon dioxide in the RuBisCO reaction. To overcome the inefficiency of RuBisCO, carboxysomes concentrate carbon dioxide inside the shell by means of co-localized carbonic anhydrase activity, which produces carbon dioxide from the bicarbonate that diffuses into the carboxysome. The resulting concentration of carbon dioxide near RuBisCO decreases the proportion of ribulose-1,5-bisphosphate oxygenation and thereby avoids costly photorespiratory reactions. The surrounding shell provides a barrier to carbon dio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symmetry In Biology
Symmetry in biology refers to the symmetry observed in organisms, including plants, animals, fungi, and bacteria. External symmetry can be easily seen by just looking at an organism. For example, the face of a human being has a plane of symmetry down its centre, or a pine cone displays a clear symmetrical spiral pattern. Internal features can also show symmetry, for example the tubes in the human body (responsible for transporting gases, nutrients, and waste products) which are cylindrical and have several planes of symmetry. Biological symmetry can be thought of as a balanced distribution of duplicate body parts or shapes within the body of an organism. Importantly, unlike in mathematics, symmetry in biology is always approximate. For example, plant leaves – while considered symmetrical – rarely match up exactly when folded in half. Symmetry is one class of patterns in nature whereby there is near-repetition of the pattern element, either by reflection or rotation. W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merosity
Merosity (from the greek "méros," which means "having parts")) refers to the number of component parts in a distinct whorl of a plant structure. The term is most commonly used in the context of a flower where it refers to the number of sepals in a whorl of the calyx, the number of petals in a whorl of the corolla, the number of stamens in a whorl of the androecium, or the number of carpels in a whorl of the gynoecium. The term may also be used to refer to the number of leaves in a leaf whorl. The adjective ''n''-merous refers to a whorl of ''n'' parts, where ''n'' is any integer greater than one. In nature, five or three parts per whorl have the highest frequency of occurrence, but four or two parts per whorl are not uncommon. Two consecutive whorls of dimerous petals are often mistaken for tetramerous petals. If all of the whorls in a given floral arrangement have the same merosity, the flower is said to be isomerous, otherwise the flower is anisomerous. For example, '' Trilli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crinoids
Crinoids are marine invertebrates that make up the class Crinoidea. Crinoids that remain attached to the sea floor by a stalk in their adult form are commonly called sea lilies, while the unstalked forms, called feather stars or comatulids, are members of the largest crinoid order, Comatulida. Crinoids are echinoderms in the phylum Echinodermata, which also includes the starfish, brittle stars, sea urchins and sea cucumbers. They live in both shallow water and in depths of over . Adult crinoids are characterised by having the mouth located on the upper surface. This is surrounded by feeding arms, and is linked to a U-shaped gut, with the anus being located on the oral disc near the mouth. Although the basic echinoderm pattern of fivefold symmetry can be recognised, in most crinoids the five arms are subdivided into ten or more. These have feathery pinnules and are spread wide to gather planktonic particles from the water. At some stage in their lives, most crinoids have a sho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subunit (other)
Subunit may refer to: * Subunit HIV vaccine, a class of HIV vaccine *Protein subunit, a protein molecule that assembles with other protein molecules *Monomer, a molecule that may bind chemically to other molecules to form a polymer * Sub-subunit, a military subunit is a component or subordinate element of a unit (military) Military organization (American English , AE) or military organisation (British English , BE) is the structuring of the armed forces of a State (polity), state so as to offer such military capability as a military policy, national defense pol ... * Subunit (format), test reporting and controlling protocol See also * Unit (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monomer
A monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or two- or three-dimensional network in a process called polymerization. Classification Chemistry classifies monomers by type, and two broad classes based on the type of polymer they form. By type: * natural vs synthetic, e.g. glycine vs caprolactam, respectively * polar vs nonpolar, e.g. vinyl acetate vs ethylene, respectively * cyclic vs linear, e.g. ethylene oxide vs ethylene glycol, respectively By type of polymer they form: * those that participate in condensation polymerization * those that participate in addition polymerization Differing stoichiometry causes each class to create its respective form of polymer. : The polymerization of one kind of monomer gives a homopolymer. Many polymers are copolymers, meaning that they are derived from two different monomers. In the case of condensation polymerizations, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T Cell
T cells (also known as T lymphocytes) are an important part of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell surface receptor, cell surface. T cells are born from hematopoietic stem cells, found in the bone marrow. Developing T cells then migrate to the thymus gland to develop (or mature). T cells derive their name from the thymus. After migration to the thymus, the precursor cells mature into several distinct types of T cells. T cell differentiation also continues after they have left the thymus. Groups of specific, differentiated T cell subtypes have a variety of important functions in controlling and shaping the immune response. One of these functions is immune-mediated cell death, and it is carried out by two major subtypes: Cytotoxic T cell, CD8+ "killer" (cytotoxic) and T helper cell, CD4+ "helper" T cells. (These are named for the presen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Number Prefix
Numeral or number prefixes are prefixes derived from numerals or occasionally other numbers. In English and many other languages, they are used to coin numerous series of words. For example: *triangle, quadrilateral, pentagon, hexagon, octagon (shape with 3 sides, 4 sides, 5 sides, 6 sides, 8 sides) * simplex, duplex (communication in only 1 direction at a time, in 2 directions simultaneously) * unicycle, bicycle, tricycle (vehicle with 1 wheel, 2 wheels, 3 wheels) * dyad, triad, tetrad (2 parts, 3 parts, 4 parts) * twins, triplets, quadruplets (multiple birth of 2 children, 3 children, 4 children) * biped, quadruped, hexapod (animal with 2 feet, 4 feet, 6 feet) * September, October, November, December ( 7th month, 8th month, 9th month, 10th month) * binary, ternary, octal, decimal, hexadecimal (numbers expressed in base 2, base 3, base 8, base&nb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentamerous Metamorphosis
''Pentamerous Metamorphosis'' is a remix album by Global Communication originally released in 1993 on Dedicated Records. It is a reworking of the ''Blood Music'' album by Chapterhouse and was originally only available as a bonus CD bundled with the Chapterhouse album. It was released as a standalone album later the same year, and then re-released in 1998 in an edited version. Track listing * "Beta Phase" is primarily a remix of Chapterhouse's ''Don't Look Now''. * "Gamma Phase" is primarily a remix of Chapterhouse's ''There's Still Life'' and ''Deli''. * "Delta Phase" is primarily a remix of Chapterhouse's ''We Are the Beautiful''. * "Epsilon Phase" is primarily a remix Chapterhouse's ''Love Forever''. Notes The 1998 re-release was remastered and had minor changes to two tracks: (Beta Phase) to remove an uncleared sample from the film ''Return of the Jedi'' and (Delta Phase) was shortened by eight bars. The removed sample: EV-9D9: "How many languages do you speak?" C-3PO ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
