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17 Cards in this Set
- Front
- Back
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What are the four most common cytoskeletal filaments? What are their approx sizes and composition?
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1. Actin filaments, 7-8nm, Actin
2. Intermediate Filaments, 10nm, Heterogenous 3. Microtubules 25nm, Tubulin 4. Myosin Filaments, variable, Myosin |
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What are MT subunits? How many protofilaments are there?
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alpha and beta heterodimers; 13 protofilaments/tube
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Polymerization of MTs occurs at which end? And is most efficient when this end is capped with what?
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A plus end capped with GTP
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Under what conditions are MT stabilized or depolymerized?
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Most stable when the + end is capped with GTP. Lease stable when GTP hydrolysis exceeds the rate of dimer addition.
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Bipolar mitotic spindles are made of what?
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MTs
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Name the two drugs that target MTs and whether they stabilize or destabilize.
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Vinblastine destablizes. Taxol stabilizes.
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What is/happens at MTOCs. What is the principle MTOC?
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Microtubule organizing center are sites where polymerizatoin of MTs is organized or initiated. The centrosome containing centrioles is the cell's principle MTOC.
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What are basal bodies?
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They are centrioles at the cell surface from which cilia extend
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What is gamma-tubulin and what is it involved in?
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It is related structurally to alpha and beta tubulin but does not form tubular structures. It exits as part of a large multiprotein complex called gamma-tubulin ring complex that is involved in the initiation of polymerization of MTs at the MTOCs. It caps the - end to prevent disassembly.
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Cilia and Flagella are composed of what kind of filament
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MTs
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How are basal bodies arranged?
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9 triplets
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What do axonemes arise from?
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The cytoskeletal component of cilium or flagellum.
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What is an axoneme? What is its arrangement?
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It is the cytoskeletal component of cilium or flagellum that arise from basal bodies. It is arranged in a 9 + 2 arrangement.
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What causes ciliary bending?
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Dynein and ATP hydrolysis that causes relative sliding between microtubules in the axoneme.
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How many ATPase domains does Dynein and Kinesin have?
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one/head - two heads
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In a neuron, where is the - end and + end of MTs relative to the soma and synapse?
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- end is in the Soma and + end is in the synapse
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How might MT motors play a role in cell division?
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They probably anchor to one MT and motor on an opposite MT - moving it in a + or - directed fashion.
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