Chapter 9-slides to know

Chapter 9-slides to know - The cytoskeleton is composed of...

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The cytoskeleton is composed of three well-defined filamentous structures- microtubules , microfilaments and intermediate filaments . Microtubules are rigid tubes composed of subunits of the protein tubulin. Microfilaments are solid, thinner structures composed of the protein actin, Intermediate filaments are tough, ropelike fibers composed of a variety of similar proteins
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Fig. 9.1 An overview of the structure and functions of the
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Function of Cytoskeleton: 1. a scaffold , providing structural support that helps maintain the shape of the cell. 2. An internal framework responsible for positioning the various organelles within the interior of the cell. 3. The machinery that moves materials and organelles within cells. 4. The force-generating apparatus that moves cells from one place to another . 5. A site for anchoring mRNAs and facilitating their translation into polypeptides 6. An essential component of the cells division machinery.
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A B C Fig. 9.6a-d Using video microscopy to follow the activities of molecular D a, bead coated with the motor protein kinesin b. the bead deposited on a microtubule c,d. the bead binds to the microtubule and begins moving along the microtubule track
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Figure 9.7 Expression of a mutant motor protein inhibits the dispersion of pigment granules in a pigment cell A control pigment cell from the amphibian Xenopus showing the black pigment granules dispersed into the elongated cellular processes a pigment cell that is overexpressing a gene for a mutant motor protein The mutant protein acts as a competitive inhibitor of the normal protein produced in the cell and inhibits dispersion of the pigment granules . This result points to the role of this motor protein in the outward transport of these membrane-bounded granules
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GDP GTP beta alpha Fig. 9.8 The structure of microtubules (MT), a) negatively stained MT b) Electron micrograph of a cross-section of a MT c) ribbon model of the alpha (a), beta (b) subunits of MT a b c 13 subunits The α/β heterodimer of tubulin. The α tubulin has a GTP which is not hydrolyzed and is non- exchangable . The β tubulin subunit has a bound GDP, which is exchanged for a GTP prior to assembly into a polymer .
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in The beta lattice (the intracellular form of microtubules). Protofilament
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This note was uploaded on 08/25/2009 for the course BIO 315 taught by Professor Steiner during the Spring '08 term at Kentucky.

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Chapter 9-slides to know - The cytoskeleton is composed of...

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