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19 Cards in this Set
- Front
- Back
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What is the structure of Kinesein (and Dynein)?
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a head (directly bonded to microtubule), a neck (flexible), a tail (interacts with vesicles/proteins on vesicles)
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Kinesein moves in what direction?
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OUT: towards + end, beta end, cell periphery (but retrograde from golgi to ER)
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Dynein moves in what direction?
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IN: towards - end, alpha end, MTOC (but anterograde from golgi to ER)
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Kinesein movement: 1. Heads have ____ and bind to ______
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ADP, microtubule
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Kinesein movement: 2. ___ falls off at this point.
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ADP falls off when head binds to microtubule
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Kinesein movement: 3. Loss of _____ causes what to happen?
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loss of ADP recruits ATP
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Kinesein movement: 4. Binding of ____ causes what change in conformation?
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Binding of ATP bends the neck of the first kinesein and moves the head of the other kinesein forward.
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Kinesein movement: 5. What happens to the first kinesein after the second has swung forward?
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ATP is hydrolyzed, and the first kinesein pops off the microtubule
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Kinesein movement: 6. What has the second kinesein become?
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The first kinesein. Go back to step 1.
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How far is one kinesein step?
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one tubulin dimer
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To what type of tubulin does kinesein bind?
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beta tubulin
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To what type of tubulin does dynein bind?
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alpha tubulin
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How fast do motor proteins move?
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1 micrometer per second. (120 steps per second!)
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Experiment to test directionality of movement?
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1. Isolate a MTOC, put in petri dish with tubulin dimers and GTP, it creates an in vitro cytoskeleton! 2. Isolate purified motor protein, attach a latex bead, add ATP. 3. See where the beads go! (inward or outward)
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COP II coated vesicles move in what direction and associate with which motor protein?
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anterograde (forward). Dynein. Move to minus end.
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COP I coated vesicles move in what direction and associate with which motor protein?
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retrograde (backward). Kinesein. Move to plus end.
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If COP I coated vesicles move backward and towards the + end of a microtubule, where is the MTOC?
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MTOC is beyond the golgi
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How does zebrafish camouflage work?
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dark stipes vs light stripes. Melanophores are pigmented granules that move along the microtubules. Alternately activate dynein and kinesein.
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Cilia and flagella are made of what kind of microtubule?
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axonmenal microtubules
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