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Unformatted text preview: 579 18.2 Binary fate decisions: the germ line versus the soma structural proteins,-tubulin and -tubulin. Each type of rod participates in higher-order networks by forming reversible cross-links with neighboring rods of its type. The different cytoskeletal systems often play different biological roles. For example, actin microfilaments often play a primary role in cellular motility, such as muscle contraction or the “crawling” movement of amebae, whereas microtubules are the cytoskeletal elements within the mitotic and meiotic spindles of cell division. The cytoskeleton performs several tasks that are im- portant to the formation of asymmetries: control of the location of the mitotic cleavage plane within the cell, control of cell shape, and directed transport of molecules and organelles within the cell. All of these tasks depend on the fact that the cytoskeletal rods are polar structures exhibiting directionality (Figure 18-3). That is, one end of a cytoskeletal rod can be chemically distinguished...
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This note was uploaded on 01/10/2011 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.
- Spring '08