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12 Cards in this Set
- Front
- Back
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What are the three main elements of the cell's cytoskeleton?
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Actin filaments, microtubules and Intermediate filaments
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What is the role of actin filaments?
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They determine shape of the cell's surface and are involved in whole-cell locomotion
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Describe the structure of actin.
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2-stranded helical polymers of globular actin molecules that are arranged in concentrated bundles. Concentrated at cell cortex.
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What is the role of the microtubule?
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To determine the positions of membrane-enclosed organelles and direct intracellular transport e.g. movement of mitochondria from cell body to axon terminals in neurons.
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Describe the structure of microtubules.
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Filaments comprise of globular tubulin proteins that for hollow cylinders (typically 13 protein filaments) thus making them strong to compression.
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What is the MTOC?
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Microtubule organising centre aka the centrosome; all microtubules are attached here.
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What is the role of the intermediate filament?
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Line inner case of nuclear membrane providing a protetive casing to DNA. Provide cell with mechanical strength and core strength.
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Describe the structure of intermediate filaments.
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Consists of many different intermediate filament proteins that are fibrous.
In epithelium, intermediate filaments span the length of it from one cell junction to another - conveys strength to whole epithelium. |
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What is the role of the motor protein?
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To move elements (i.e. other filaments, organelles etc) along a microtubule using energy derived from repeated hydrolysis of ATP. Each has two binding domains: one for the filament microtubule its bound to and one for another element.
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What are the two types of micrtubule motor protein?
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Kinesins; move towards positive end
Dynesins; move towards negative end |
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How are the subunits of cytoskeletal filaments held together?
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Weak non-covalent bonds, thus allowing constant rapid assembly and disassembly.
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How are cytoskeletal filaments themselves held together?
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Non-covalent and hydrophobic protein-protein interactions. Thermally stable.
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