Term
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Definition
| layer closely applied to the outer surface of plasma membrane; contains carbohydrates along with extracellular materials that have been secreted by cell |
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Term
| extracellular matrix (ECM) |
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Definition
| organized network of extracellular materials that is present beyond the immediate vicinity of the plasma membrane; play integral role in determining shape and activities of cell |
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Term
| basement membrane (basal lamina) |
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Definition
| thickened layer of approximately 50 to 200nm of ECM that surrounds muscle and fat cells and underlies the basal surface of epithelial tissues |
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Term
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Definition
| family of fibrous glycoproteins known for their high tensile strength that function exclusively as part of the ECM |
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Term
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Definition
| protein-polysaccharide complex consisting of core protein with chains of glycosaminoglycans; capable of binding huge # of cations, which attracts water molecules; form porous hydrated gel that is "packing" material to resist compression |
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Term
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Definition
| any of a group of glycoproteins of cell surfaces, blood plasma, and connective tissue that promote cellular adhesion and migration |
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Term
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Definition
| glycoprotein component of connective tissue basement membrane that promotes cell adhesion |
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Term
| matrix metalloproteinases (MMPs) |
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Definition
| family of zinc-containing enzymes that act in the extracellular space to digest various extracellular proteins and proteoglycans |
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Term
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Definition
| superfamily of integral membrane proteins that bind specifically to extracellular molecules |
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Term
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Definition
| family of IM glycoproteins that recognize and bind to specific arrangements of carbohydrate groups projecting from the surface of other cells |
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Term
| immunoglobulin super family (IgSF) |
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Definition
| wide variety of proteins that contain domains composed of 50-70 AA that are homologous to domains that make up the polypeptide chains of blood-borne antibodies |
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Term
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Definition
| family of related glycoproteins that mediate Ca2+ dependent cell-cell adhesion |
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Term
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Definition
| specialized adhesive junc particularly common in epithelia; membranes separated by 20-35nm; sites where cadherin is concentrated; cells held together by linkages between extracellular domains of cadherin molecules that bridge the gap between neighboring cells |
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Term
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Definition
| disc-shaped adhesive junctions containing cadherins found in a variety of tissues, mostly epithelia, located basal to the adherins junc.; dense cytoplasmic plaques on the inner surface serve as sites of anchorage for looping intermediate filaments |
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Term
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Definition
| specialized adhesive structure at the basal surface of epithelial cells that functions to attach the cells to the underlying basement membrane; contains a dense plaque on the inner surface with keratin-containing filaments coursing out into the cytoplasm |
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Term
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Definition
| adhesive structures characteristic of cultured cells adhering to the surface of a culture dish; membrane in region contains clusters of integrins that connect extracellular material to actin-containing microfilament system of cytoskeleton |
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Term
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Definition
| transfer of information across the plasma membrane |
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Term
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Definition
| specialized contacts that occur at the very apical end of the junctional complex between adjacent epitelial cells; make contact at intermittent points, where integral proteins of the two adjacent membranes meet |
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Term
| plasmodesma (plasmodesmata) |
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Definition
| cytoplasmic channels that connect most plant cells and extend between adjacent cells directly through cell wall; line with plasma membrane |
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Term
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Definition
| rigid, nonliving structure that provides support and protection for the cell it surrounds |
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Term
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Definition
| bundles of cellulose molecules that confer rigidity to the cell wall and provide resistance to pulling forces |
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Term
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Definition
| branched polysaccharides of the plant cell wall whose backbone consists of one sugar and sidechains of other sugars |
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Term
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Definition
| heterogenous class of negatively charged polysaccharides that make up the matrix of the plant cell wall; hold water and form a gel that fills in the spaces between fibrous elements |
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Term
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Definition
| mediate dynamic activities (i.e. facilitate cell growth); macromolecule of the matrix of cell wall |
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Term
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Definition
| structure between the cytoplasm of two newly formed daughter cells that gives rise to a new cell wall in plant cells |
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Term
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Definition
| walls of a growing plant cell; allow for extensibility |
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Term
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Definition
| thicker cell walls found in most mature plant cells |
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Term
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Definition
| functionally and structurally interrelated group of membranous cytoplasmic organelles including the endoplasmic reticulum, Golgi, endosomes, lysosomes, and vacuoles |
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Term
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Definition
| shuttles, formed by budding from a membrane compartment, that carry materials between organelles |
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Term
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Definition
| route through the cytoplasm by which materials are synthesized in the ER or Golgi, modified during passage through Golgi, and transported across cytoplasm to various destinations |
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Term
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Definition
| alternative term for biosynthetic pathway because many of the material synthesized in the pathway are destined to be discharged outside the cell |
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Term
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Definition
| discharged outside the cell |
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Term
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Definition
| discharge of materials synthesized in the cell into the extracellular space in a continual manner |
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Term
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Definition
| discharge of materials synthesized in the cell that have been stored in membrane-bound secretory granules in the peripheral regions of cytoplasm, occurring in response to an appropriate stimulus |
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Term
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Definition
| large, densely packed, membrane-bound structure containing highly concentrated secretory materials that are discharged following a stimulatory signal |
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Term
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Definition
| route for moving materials from outside the cell to compartments, such as endosome and lysosome, located within cell |
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Term
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Definition
| technique for visualizing biochemical processes by allowing an investigator to determine the location of radioactively labeled materials within a cell |
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Term
| green fluorescent protein (GFP) |
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Definition
| fluorescent protein encoded by jellyfish that is widely used to follow events in living cells |
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Term
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Definition
| to mechanically rupture cells |
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Term
| subcellular fractionation |
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Definition
| approach that allows different organelles having different properties to be separated from one another |
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Term
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Definition
| heterogeneous collection of vesicles formed from the endomembrane system after homogenization |
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Term
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Definition
| experimental system to study cellular activities that does not require whole cells; typically contain a preparation of purified proteins and subcellular fractions and are amenable to experimental manipulation |
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Term
| endoplasmic reticulum (ER) |
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Definition
| system of tubules, cisternae, and vesicles that divides the fluid content of the cyoplasm into a luminal psace within the ER membrane and a cytosolic space outside the membranes |
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Term
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Definition
| part of ER that has ribosomes attached; extensive membranous organelle composed primarily of flattened sacs separated by cytosolic space; functions: synthesis of secretory proteins, lysosomal proteins, IM proteins, and membrane lipids |
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Term
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Definition
| part of ER without attached ribosomes; typically tubular and from an interconnecting system of pipelines curing through the cytoplasm in which they occur; functions: vary from cell to cell, synthesis of hormones, detoxification of wide variety of organic compounds, mobilization of glucose from glucose-6-phosphate, and sequestration of calcium ions |
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Term
| luminal (cisternal) space |
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Definition
| region of fluid content of the cytoplasm enclosed by the membrances of the ER or Golgi |
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Term
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Definition
| special series of AA located at the N-terminus portion of newly forming proteins that triggers the attachment of protein-forming ribosome to ER membrane and mvmnt of the nascent polypeptide into the cisternal space of ER |
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Term
| signal recognition particle (SRP) |
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Definition
| particle consisting of six distinct polypeptides and a small RNA molecules that recognizes the signal sequence as it emerges from the ribosome; SRP binds to signal sequence then ER membrane |
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Term
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Definition
| situated within the ER membrane, binds specifically to SRP-ribosome complex |
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Term
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Definition
| protein-lined channel embedded in the ER membrane; the nascent polypeptide is able to move through the translocon in its passage from the cytosol to the ER lumen |
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Term
| GTP-binding proteins (G proteins) |
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Definition
| key regulatory roles in many different cellular processes, can be present in at least two alternate conformations; active with GTP and inactive with GDP |
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Term
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Definition
| proteolytic enzyme that removes the N-terminal portion including the signal peptide of the nascent polypeptide synthesized in the RER |
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Term
| phospholipid-transfer proteins |
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Definition
| proteins whose function is to transport specific phopholipids through the aqueous cytosol from one type of membrane compartment to another |
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Term
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Definition
| large family of enzymes that transfer specific sugars from a specific donor to a specific receptor |
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Term
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Definition
| hydrophobic molecules built from more than 20 isoprene units that assembles the basal, or core, segment of carbohydrate chains within glycoproteins |
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Term
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Definition
| cells contain various mechanisms that ensure that the proteins and nuclic acis they synthesize have the appropriate structure |
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Term
| unfolded protein response (UPR) |
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Definition
| comprehensive response that occurs in cells whose ER cisternae contain an excessively high concentration of unfolded or misfolded proteins; sensor detect this and trigger a pathway that leads to the synthesis of proteins that can alleviate the stress in the ER |
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Term
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Definition
| network of smoother membranes organized into characteristic morphology, consisting of flattened, disc-like cisternae with dilated rims and associated vesicles and tubules; functions: porcessing plant where modification of proteins occurs |
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Term
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Definition
| cis-most face of the organelles that is composed of interconnected network of tubules; functions primarily as a sorting station that distinguishes between proteins to be shipped back to the ER and those that are allowed to proceed to the next Golgi station |
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Term
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Definition
| cisternae of the Golgi complex closest to the ER |
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Term
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Definition
| cisternae of the Golgi between the cis and trans |
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Term
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Definition
| cisternae of the Golgi farthest from the ER |
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Term
| trans Golgi network (TGN) |
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Definition
| network of interconnected tubular elements at the trans end of the Golgi that sorts and targets proteins fro delivery to their ultimate destination |
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Term
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Definition
| vesicles that bud from a membrane compartment typically possess a multi-subuinit protein coat that promotes buding process and binds specific membrane proteins |
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Term
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Definition
| carry material from ER to Golgi |
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Term
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Definition
| carry material from Golgi to ER |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| family of monomeric G proteins involved in vesicle trafficking |
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Term
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Definition
| key proteins that mediate the process of membrane fusion |
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Term
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Definition
| located int he membrane of target compartments |
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Term
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Definition
| incorporate into the membranes of transport vesicles during buddying |
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Term
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Definition
| process of membrane fusion and content discharge during which the membrane of the secretory granule or vesicle comes into contact with the overlying plasma membrane with which it fuses, thereby forming an opening through which the contents of the granule or vesicle can be released |
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Term
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Definition
| hydrolytic enzymes with optimal activity at an acid pH |
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Term
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Definition
| regulated destruction of cellular materials and their replacement |
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Term
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Definition
| destruction of organelles and their replacement during which an organelle is surrounded by a double membrane; membrane then fuses with lysosome |
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Term
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Definition
| single membrane-bound, fluid filled structure that comprises as much as 90% of the volume of many plant cells |
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Term
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Definition
| membrane that bounds the vacuole of a plant cell |
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Term
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Definition
| mechanism for the uptake of fluid and solutes into a cell to compartments located within the cell |
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Term
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Definition
| process by which particulate materials are taken into cells; materials are enclosed within a fold of the plasma membrane which buds into the cytoplasm to form a vesicle called a phagosome |
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Term
| receptor-mediated endocytosis |
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Definition
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Term
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Definition
| specialized domains of the plasma membrane; serve as collection points for receptors that bind substances that enter the cell by means of endocytosis |
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Term
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Definition
| organelles of the endoyctic pathway |
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Term
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Definition
| materials taken up by endocytosis are taken to them for sorting |
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Term
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Definition
| function as destination sites of lysosomal enzymes transported from Golgi |
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Term
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Definition
| elaborate interactive network composed of three well-defined filamentous structures: microtubules, intermediate filaments, microfilaments; structural support, internal framework, positioning various organelles, required for movement; focre-generating elements; sites for anchoring, signal transducer, transmit cell-cell info |
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Term
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Definition
| hollow, cylindrical cytoskeletal structures, whose wall is composed of the protein tubulin; polymers assembled from (alpha)(beta)-tubulin heterodimers that are arranged in rows, or protofilaments; rigid; act as support |
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Term
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Definition
| solid cytoskeletal structures composed of a double-helical polymer of the protein actin; play a key role in virtually all types of contractility and motility within cells |
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Term
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Definition
| (IFs) strong, ropelike cytoskeletal fibers that may be composed of a variety of protein subunits (depends on cell type) capable of assembling into similar types of filaments; thought to provide mechanical stability to cells and provide specialized, tissue-specific functions |
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Term
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Definition
| field of engineering involving the development of tiny "nanomachines" capable of performing specific activities in a submicroscopic world |
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Term
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Definition
| longitudinally arranged rows of globular subunits of a microtubule that are aligned parallel to long axis of the tubule |
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Term
| microtubule-associated proteins (MAPs) |
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Definition
| proteins other than tubulin contained in microtubules obtained from cells; may interconnect microtubles to form bundles; cross-bridges connecting microtubules to each other; increase stability; alter rigidity; influence rate of assembly |
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Term
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Definition
| plus end-directed motor protein that moves membranous vesicles and other organelles along microtubules through cytoplasm |
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Term
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Definition
| term applied to proteins that are capable of moving considerable distances along their track or template without dissociating from it |
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Term
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Definition
| exceptionally large, cargo-carryi9ng, multisubuint motor protein that moves along microtubules toward their minus end |
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Term
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Definition
| huge protein composed of numerous polypeptide chains; functions in mvmt of chromosomes during mitosis and minus-end directed microtubular motor for the mvmt of vesicles |
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Term
| microtubule-organizing centers (MTOCs) |
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Definition
| variety of specialized structures that exert a role in initializing microtubule formation |
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Term
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Definition
| complex structure that contains two barrel-shaped centrioles surrounded by amorphous, electron dense PCM |
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Term
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Definition
| cylindrical structures, containnine evenly spaced fibrils each which appears in cross section as a band of three microtubules; always found in pairs situated at right angles of each other |
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Term
| pericentriolar material (PCM) |
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Definition
| electron-dense, amorphous; where microtubules are nucleated |
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Term
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Definition
| type of tubulin that plays a critical component in microtubule nucleation |
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Term
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Definition
| structure that resides at the base of the cilium or flagellum |
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Term
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Definition
| term that relates to the assembly/dis assembly properties of the plus end of microtubule; growing and shrinking microtubules can coexist in one region of cell; switch back and forth unpredictably from growing to shrinking |
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Term
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Definition
| hairlike motile organelles that project from the surface of a variety of eukaryotic cells; tend to occur in large number on surface |
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Term
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Definition
| hairlike motile organelles that project from the surface of a variety of eukaryotic cells; essentially the same structure as cilia but present in much fewer numbers |
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Term
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Definition
| central, microtubule-containing core of a cilium or flagellum; most consist of nine peripheral doublets, two central microtubules, and numerous accessory structures |
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Term
| intraflagellar transport (IFT) |
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Definition
| process in which particles are moved in both directions between the base of a flagellum or cilium and its tip; force that drives IFT is generated by motor proteins that track along the perfipheral doublets of the axomene |
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Term
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Definition
| huge protein responsible for conversion of the chemical energy of ATP into the mechanical energy of ciliary locomotion |
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Term
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Definition
| loosely packed bundles of intermediate filaments located within the cytoplasm of neurons; have long axes that are oriented parallel to that of the nerve cell axon and are composed of three distinct proteins |
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Term
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Definition
| globular, cytoskeletal protein that polymerizes to form flexible, helical filament capable of interacting with myosin; provide mechanical support for eukaryotic cells, determine the cell's shape and enable cell movements |
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Term
| conventional (type II) myosin |
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Definition
| family of myosins, first identified in muscle tissue, that are the primary motors for muscle contractions; needed for splitting a cell in two during cell division, generating tension at focal adhesions |
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Term
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Definition
| have many diverse roles including organelle transport (I, III-XVIII) |
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Term
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Definition
| think cylindrical strands found within muscle fibers; composed of repeating linear arrays of sarcomeres |
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Term
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Definition
| contractile units that give skeletal muscle cells their striated appearance |
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Term
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Definition
| consists primarily of actin and are arranged in a hexagonal array around each thick filament with each thin filament situated between two thick filaments |
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Term
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Definition
| consist primarily of myosin and are surrounded by a hexagonal array of thin filaments |
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Term
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Definition
| point of contact of a terminus of an axon with a muscle fiber, site of transmission of nerve impulses from the axon across the synaptic cleft to the muscle fiber |
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Term
| excitation-contraction coupling |
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Definition
| steps that link the arrival of a nerve impulse at the muscle plasma membrane to the shortening of the sarcomeres deep within the muscle fiber |
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Term
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Definition
| membranous folds along which the impulse generated in a skeletal muscle cell is propagated into the interior of the cell |
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Term
| sarcoplasmic reticulum (SR) |
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Definition
| system of cytoplasmic, Ca2+-storing SER membranes in muscle cells that forms a membranous sleeve around the myofibril |
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Term
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Definition
| nearly 100 different protiens belonging to numerous families that affect the assembly of actin filament, their physical properties, and their interactions with one another and with other cellular organelles |
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Term
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Definition
| leading edge of a moving fibroblast, which is extended out from the cell as a broad, flattened, veil-like projection that glides over the substratum |
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Term
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Definition
| distal tip of a growing neuron that contains the locomotor activity required for axonal extension |
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