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203 Cards in this Set
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G-Actin
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monomer of microfilaments
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F-Actin
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helical polymer of microfilaments
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None
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lag phase of actin polymerization
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formation of actin trimer (nucleation site)
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Actin-binding proteins
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versatile family of proteins that crosslink actin filaments into loose gels, bind them into stiff bundles, attach to PM, or move them
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None
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minimyosin (myosin 1)
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motor protein of actin filaments in non-muscle cells
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filamin
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protein that crosslinks actin filaments into gel
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spectrin
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protein that crosslinks filaments to PM by their sides
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fimbrin
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protein that bundles actin filaments
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α actinin
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protein that bundles actin filaments and links actin filament to viniculin at focal contacts
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gel solin
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calcium dependent protein that severs or fragments actin filaments
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cap-Z
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protein that caps the positive end of actin
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profilin
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protein that binds actin monomers and inhibits polymerization
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Cytochalasins
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drug that blocks cell movement by binding to + end of actin to block polymerization and inhibit motility, phagocytosis, organelle and vesicle trafficking and production of lamellipodia and filopodia
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Focal contacts
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place that actin attaches the cell PM to extracellular matrix
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Integrins
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family of transmembrane proteins that link ECM's fibronectin w/ cytoplasmic actin filaments of stress fibers with attachment proteins
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talin
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protein that links viniculin to integrin at focal contacts
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viniculin
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protein that links α actinin to talin at focal contacts
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integrins linkage at focal contacts
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transmembrane protein that links talin to fibronectin
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ankyrin
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protein mainly responsible for attaching the spectrin cytoskeleton to red cell PM
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filopodia
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thin stiff protrusions of the cell surface that form and reform quickly and contain a bundle of actin filaments
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lamellipodia
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thin sheetlike processes of cell surface made of actin filament involved in cell movement
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tubulin
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dimer of α and β tubulin. The subunit of microtubules
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protofilaments
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long parallel rows into which tubulin molecules align; 13 make a microtubule
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kinesins
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motor protein family that move along microtubules. Associated with ER
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dyneins
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motor protein family that move toward the α end of microtubules. Ciliary and cytoplasmic varietys exist and are associated with the golgi
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colchicine
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antimitotic drug which binds to free tubulin and prevents polymerization
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taxol
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antimitotic drug which binds to microtubules and prevents depolymerization
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γ-tubulin
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ring shaped structure of centrosome which acts as the nucleation-site of a microtubule
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dynamic instability
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property of microtubules based on rapid polymerization and depolymerization (if GTP of plus end is hydrolyzed before the next tubulin is added)
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centrioles
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pair of cylindrical microtubule structures in the centrosome
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arrangement of microtubules in centrioles
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9 + 0
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arrangement of microtubules in cilia
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9 + 2
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basal bodies
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accumulation of centrioles beneath the PM which initiate tubulin polymerization to form the axoneme of cilia or flagella
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arrangement of microtubules in basal bodies
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9 + 0
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axoneme
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core of each cilium with 9 microtubule doublets around a pair of unjoined mt's
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ciliary dynein
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protein that forms the arms that extend from subfiber A and hydrolyze ATP to generate a sliding force that moves cilia
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nexin
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protein that forms bridges to link adjacent doublets in axonemes
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radial spokes
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link the doublets to the sheath in axonemes
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sheath
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surrounds the central microtubule pair of axonemes
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effective stroke
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stiff rapid forward stroke of cilia
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recovery stroke
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slower bending stroke of cilia
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keratins
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cytoplasmic IF in epithelial cells and their derivatives
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vimentin
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IF in cytoplasm of cells of mesenchymal origin
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neurofilaments
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IF in cytoplasm of neurons
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lamins
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IF in nucleus
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filaggrin
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protein in epidermis of skin that bundles keratin IF into tonofilaments
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tonofilaments
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bundles of keratin IF
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Gated Transport
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Type of protein transport from the cytosol to the nucleus
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TransmembraneTransport
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Type of transport from the cytosol to the ER, Mitochondria, or peroxisomes
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Vesicular Transport
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Type of transport from the ER to the Lysosomes, golgi and cell curface
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Proteolysis
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enzymatically break down proteins into constituent amino acids
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Proteasomes
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large complexes of proteolytic enzymes
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Ubiquitin
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small protein that covalently attaches to proteins to mark them for destruction and to be recognized by proteasomes
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Cristae
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folds of the inner mitochondrial membrane
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Porins
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transport proteins which form large aqueous channels through the lipid bilayer of the mitochondria's outer membrane. Form a Beta barrel
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Inner Mitochondrial membrane components:
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ETC enzymes (FMN, coenzyme Q, cytochrome a,b,c), succinate dehydrogenase, ATP synthase
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Matrix Comparment contents:
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TCA enzymes, fatty acid β-oxidation enzymes, DNA, mRNA, tRNA, rRNA, Ca and Mg granules
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None
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Peroxisomes
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spherical to ovoid membrane bound organelles w/ 50 oxidative enzymes
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catalase
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uses H2O2 to oxidize other substrates like alcohols, formaldehydes and formic acid (H2O2 + R'H2 --> R' + 2 H2O)
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Superoxide dismutase
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naturally occuring enzyme in peroxisome that disposes of free radicals
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transporter
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proteinaceous ring that occupies center of Nuclear pore complex and is supported by the scaffold
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Cage
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on the nuclear side of the NPC fibrils converge to form this structure
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Exportins
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transport macromolecules (RNA) from the nucleus to cytoplasm
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Importins
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transport cargo (like protein subunits of ribosomes) from the cytosol to the nucleus
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Contact sites
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Sites of adhesion between the inner and outer mitochondrial membranes through which unfolded proteins are translocated into the matrix from the cytosol
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Signal for protein to enter the mitochondria
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a positive charge on the N- terminus; 20-80 amino acids in length with an α helix; removed by signal peptidase once in destination
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Signal for protein to enter the nucleus; NLS
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short signal located anywhere within the polypeptide which is not removed and binds to the nuclear import receptors which direct it to the NPC; unidirectional transport only
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None
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Signal for protein to enter peroxisomes:
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3 amino acid sequence on the C-terminal that remains on protein
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cistern
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lumen of the endoplasmic reticulum
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Signal recognition particles (SRP)
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particles in the cytosol that recognize protein ER signal sequence that attach to the P site and halts translation of the protein and migrates to the rough ER with the protein
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SRP receptor, docking protein
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Contacts the SRP and with ribosomal receptors attaches the polysome to the cytoplasmic surface of the ER; the SRP is released and translation resumed
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None
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protein translocation channel
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channel in ER membrane through which the growing polypeptide chain inserts into a pore in the ER membrane
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None
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Stop transfer sequence
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sequence of hydrophobic amino acids that releases the polypeptide chain from the protein translocation channel so it will drift into the bilayer of the ER forming an α-helix of the transmembrane protein (N-terminal in the lumen)
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None
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start transfer sequence
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er signal sequence in the middle of the polypeptide and ends up forming a transmembrane protein that passes multiple times through the PM
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core region
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5 sugars (3 are mannose) of the 14 oligosaccaride to glycosylate proteins
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KDEL @ C-Terminal
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sorting signal on proteins that directs them away from the Golgi apparatus (or to stay in the ER)
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Exocytosis
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process of discharging large cellular products through plasma membrane
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acid phosphatase
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enzyme in all lysosomes
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primary lysosomes
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lysosomes that haven't entered a digestive event
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mannose-6-phosphate
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tag for lysosomal proteins; tagged in the CGN then sorted into clathrin coated transport vesicles
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None
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KFERQ
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signal on protein to be taken up by lysosomes
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heterophagy
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process whereby lysosomes digest materials taken into cells from its environment by endocytosis
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Residual body
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any undigested materials in the phagosome or secondary lysosome which are released back into the extracellular fluid by exocytosis
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profesional phagocytes
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macrophages and neutrophils
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Autophagy
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process by which worn out organelles are digested
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autolysis
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process by which lysosomal enzymes destroy their own cell
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COP-I
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mediated transport vesicle from CGN to ER in retrograde transport
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None
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COP-II
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involved in anterograde transport from the ER to CGN
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SNAREs
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family of transmembrane proteins involved in vesicle docking with unique recognition to ensure that transport vesicles fuse with only the correct membrane
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None
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NSF and SNAPs
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fusion proteins which catalyze membrane fusions and form fusion complex that provide the means to cross this energy barrier
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apical domain
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region of PM that borders luminal space
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Basolateral domain
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region of PM in contact with extracellular matrix
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microvilli
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nonmotile rigid bundle of microfilaments bound by villin with + end at the tip
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terminal web
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dense network of actin filaments, spectrin and cytokeratin (IF)
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striated border microvilli
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shortest microvilli uniform in length and found on intestinal epithelium
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brush border
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microvilli that are longer and less uniform and found in proximal tubules of nephrons
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stereocilia
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long, nonmotile microvilli found in epididymal epithelium and hair cells in the inner ear
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intercellular secretory canaliculi
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increase surface area between cells for exocytosis in glands and terminate blindly above basal lamina
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basal infoldings
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invaginations of basal PM to increase basal contact SA with ECM; form labrynth that creates basal striations with mitochondria between
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What confine transport proteins to their appropriate domains by acting as a diffusion barrier?
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tight junctions (zonula occludens)
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zonula occludens (tight junction)
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junction between cells composed of strands of long rows of specific transmembrane proteins in each cells PMs which join directly to occlude intercellular space
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claudin
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protein in tight junctions that form linear fibrils to create diffusion barriers for solutes, ions and water
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None
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occludin
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transmembrane protein found in tight junctions that interacts with 4 major intracellular peripheral proteins
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None
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fascia occludens
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junction found between capillary endothelial cells
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zonula adherens
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encircles each cell near apex just below tight junction. Calcium dependent
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None
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e-cadherin
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transmembrane linker protein that mediates zonula adherens between epithelial cells
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desmosomes
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anchoring sites for IF to form a continuous structure throughout the tissue
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basal lamina
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specialized mat of ECM @ the interface between epithelium and connective tissue
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α6β4
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integrin found in hemidesmosomes and is the only integrin to connect intermediate filament
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Junctional complex
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tight junction + zonula adherens + desmosome
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connexons
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transmembrane proteins that align to form a hydrophilic channel between two cells in gap junctions
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paracrine communication
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uses local chemical mediators which are rapidly taken up and destroyed or immobilized and can only act on immediate environment
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endocrine communication
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specialized cells secrete hormones (steroids and water soluble hormones) that travel trough vasculature to influence cells over greater distances.
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synaptic signalling
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cells secrete neurotransmitters at specialized junctions (synapses)
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syncytium
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secondary union of originally separate cells and the precursors are nonfunctional
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perinuclear cisterna
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space that separates inner and outer nuclear membrane
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nuclear lamina
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layer made of IF (lamin) that separates the nuclear envelope from regions of peripheral heterochromatin
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snRNPs- small nuclear ribonucleoprotein particles
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proteins that assist in splicing to produce mRNA
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Fibrillar region
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nucleolar region made of ribosomal DNA that codes for the production of rRNA that is actively being transcribed
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Granular region
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nucleolar region made of maturing preribosomal subunit particles
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Nucleolar-orgainizing regions
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parts of chromosomes 13, 14, 15, 21,and 22 gene loci that encode rRNA and are located in the Nucleolus
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heterochromatin
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highly condensed, transcriptionally inactive chromatin
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euchromatin
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extended, dispersed transcriptionally active chromatin
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constituitive heterochromatin
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heterochromatin that is never uncoiled
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facultative heterochromatin
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packed chromatin that contains coding sequences and may or man not be unfolded
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barr body
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type of facultative heterochromatin that is never uncoiled
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generation time
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time of one cell cycle and dependent mainly on the G1
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G1
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phase of cell cycle of synthesis of proteins and specialized functions of the cell
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S
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phase of cell cycle when DNA is duplicated and histones are produced
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G2
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phase of cell cycle when the cell is prepared for mitosis
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G0
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phase of cells that have left the cell cycle, called end cells
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stem cells
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cells of same type that haven't become sufficiently specialized and can undergo mitosis and continue to cycle.
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progenitor cells
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cells that can proliferate but usually lose capacity for self reneal and become committed to roduce a sigle type of end cell
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Cyclin-dependent kinases
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proteins that for a complex with cyclins and then phosphorylate other proteins to initiate or block activities crucial to progress through cell cycle
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p53
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tumor suppressor protein that is a Cdk inhibitor and is absent in many cancers
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D-type Cyclins
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cyclins needed at the G1 checkpoint to activate Cdk 4 and 6 and allow cells to progress to the S phase
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MPF- M phase promoting factor
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a cyclin B-Cdc 2 complex with kinase activity that is the command to enter mitosis that accumulates in G2 at the checkpoint
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kinetochore
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protein structure that links centromere of chromosomes to spindle microtubules during mitosis
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telomerase
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enzyme that elongates existing telomere making cells 'immortal'. Only activated in cancer
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satellites
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DNA attached to short arms of chormosomes 13, 14, 15, 21 and 22 bye secondary constriction and contains rRNA genes. These fuse to form the nucleolus after mitosis
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apoptosis
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active form of cell death initiated by the cell. Programmed elimination of the cell
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caspases
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enzymes which degrade regulatory and structural proteins in nucleus and cytoplasm.
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pyknosis
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chromatin condensation that occurs in apoptosis
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Starlings law of capillaries
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the volume of fluid and solutes reabsorbed is approximately the volume filtered
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glycosaminoglycans (GAGs)
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long, inflexible, unbranched polysaccharides w/ amino sugar which are negative and have a slippery texture
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aggrecan
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proteoglycan expressed in cartilage with keratan sulfate and chondroitin sulfate as the GAGs
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perlecan
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proteoglycan found with all cells making basal lamina that is made with heparan sulfate
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RGD sequence
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simple 3-peptide sequence that is the integrin binding sites of many adhesive proteins
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fibronectin
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large plycoprotein dimer with binding sites for extracellular components and integrins. The main product of fibroblasts. Involved in adhesion of cells to ECM
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laminin
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large glycoprotein composed of 3 large polypeptide chains with binding sites for heparan sulfate, type IV collagen, entactin and PM. Located in the Basal Lamina
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Entactin
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glycoprotein that binds to laminin and type IV collagen in the basal lamina
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Type I Collagen
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most common collagen; secreted by fibroblasts and provides tensile strenth in connective tissues
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Type II Collagen
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fill the extracellular matrix of cartilage
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Type III Collagen
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called reticular fibers; highly glycosylated collagen that forms thin fibers
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Type IV Collagen
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Sheets that surround organs and epithelia. Found in the basal lamina and external lamina for support and filtration
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Type VII collagen
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anchoring collagen found in epidermal-dermal junctions that links type IV collagen of the basal lamina to underlying connective tissue
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procollagen peptidase
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protein on E-surface of PM that cleaves registration peptides from procollagen to form tropocollagen
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propeptides or registration peptides
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guide the formation of triple helical structure and prevent intracellular formation of collagen fibers
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lysyl oxidase
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forms covalent crosslinks between tropocollagen molecules and tropoelastin molecules
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fibrillin
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glycoprotein distributed mainly as microfibrils on the elastic fiber surface
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basal laminae
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mats of specialized ECM (mostly type IV collagen) that underlie all epithelial cell cheets and tubes and surround individual muscle, fat and schwann cells
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lamina rara
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layer of basal lamina adjacent to basal PM and made of heparan sulfate (perlecan)
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lamina densa
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electron dense layer of basal lamina just beneath the lamina rara. Made mostly of type IV collagen
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lamina reticularis
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3rd layer of basal lamina that isn't always present. Connects the basal lamina to connective tissue below and composed of type III collagen
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Function of Na+ channels
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generating and propagating action potentials in excitable cells
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function of K+ channels
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control of excitability and shaping of electrical signals
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Function of Ca++ channels
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neurotransmitter release, muscle contraction and intracellular signalling pathways
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hyperkalemic periodic paralysis
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an Na+ chanenelopathy revealed when extracellular K+ is raised. Channel doesn't inactivate properly and action potential can't develop.
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tetrodotoxin (TTX)
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neurotoxin that is highly specific blocker of voltage-gated Na+ channels. Leads to respiratory paralysis and is found in puffer fish
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local anesthetics- novacain, lidocain
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block voltage gated Na channels in axon and prevent conduction of nerve impulses
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Lamber-eaton Myasthenic Syndrome (LEMS_
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autoimmune disease that impairs calcium influx and reduces transmitter relase at neuromuscular junction resulting in muscle weakness
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halothan
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anestheic that opens the leak K+ channels
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nifedipin and verapamil
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drugs used in the treatment of cardiovascular disease by blocking Ca++ channels
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3,4 Diaminopyridine
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drug used to treat LEMS by blocking K+ channel and prolongs the action potential
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acetylcholine receptors
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ligand gated channels at neuromuscular junction involved in excitatory neurotransmission
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glutamate receptors
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ligand gated channels at CA3-CA1 hippocampal synapse
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GABA receptors
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ligand gated channels at hippocampal synapses
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Nicotinic acetylcholine receptor
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ligand gated channel at neuromuscular junction that bind Ach and allows Na+ and K+ flux and induces depolarization which increases Ca++ and results in muscle contraction
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hyperpolarized
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a membrane potential which becomes more negative
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depolarized
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a membrane potential which becomes less negative
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acetylcholinesterase
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breaks Ach into acetate and choline and terminates signal
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congenital myasthenic syndrome
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this is a slow channel syndrome present at birth that is caused by mutations on Ach receptors causing weakness, rapid fatigue, and muscle atrophy
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D-Tubocurarine
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competetive inhibitor of Ach that causes paralysis and death by asphyxiation
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Vercoronium, Pancuronium, and Rocuronium
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synthetic chemicals that cause parlaysis by competitively inhibiting Ach receptors. Used in surgical procedures
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α bungarotoxin
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snake toxin that binds competetively and irriversibly to Ach receptors
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Succinycholine
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Ach R agonist that binds and causes depolarization and is used as a muscle relaxant
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Nicotine
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Ach R agonist that binds at same sites as ACh and can cause muscle contraction
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Myasthenia Gravis
|
autoimmune neuromuscular disease caused by the destruction of peripheral NACh receptors causing muscle weakness, movement deficit and fatigue
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None
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Picrotoxin
|
noncompetetive blocker of GABA
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Benzodiazapine
|
anxiolytic drug that increases GABA activity and is used for anxiety disorders and insomnia
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Barbituates
|
anticonvulsant and sedative drug that increases GABA activity. Used for epilepsy, anesthesia and anxiety
|
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Hormone response elements
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DNA sequences where steroid receptor complexes bind and regulate rate of transcription
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Gs
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G-protein that stimulates AC and activates protein kinase A
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Gi
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G-protein that inhibits AC and inhibits protein kinase A
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Gq
|
G-protein that is coupled to Phospholipase C which increases DAG, and in turn IP3 and Ca++ and activates protein kinase C
|
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Cholera toxin
|
bacterial toxin that stimulates Gs and causes and excess production of cAMP
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Pertussis Toxin
|
bacterial toxin that inhibits Gi and cases excess cAMP
|
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Sos
|
guanine nucleotide exchange factor for Ras that is attracted by Grb2 in the signaling event of tyrosine kinase receptor
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GTPase activating proteint (GAP)
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hydrolyzes GTP and inactivates Ras
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Restriction Point
|
the point in G1 when the cell cycle stops being GF dependent
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Oncogene
|
a mutated protein of the cell cycle control system that is constituitively activated, Ras, myc, fos, jun
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Tumor supressor gene
|
protein that inhibits cell cycle progression- Rb, p53
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Akt pathway
|
signaling effect of neurotrophins binding to receptor tyrosine kinase that prevents cell death
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