Actin Filaments - cytoplasmic streaming Intermediate...

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Actin Filaments (Microfilaments) Actin filaments are long, thin fibers composed of 2 chains of protein wrapped around each other. They occur in bundles or meshlike networks which provide mechanical support and determine the shape of the cell. Because they can assemble and disassemble quickly, the shape of a cell can change rapidly. Movement in eukaryotic cells Actin filaments assist in the movement of nearly all eukaryotic cells. Microvilli and pseudopodia move by the action of actin filaments. Actin filaments are important in muscle contraction. During cell division a ring of actin filaments that surrounds the cell constricts, pinching the cell into two. The chloroplasts of plant cells move (circulate) by following actin filaments, a process called
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Unformatted text preview: cytoplasmic streaming . Intermediate Filaments Intermediate filaments are composed of long, threadlike protein molecules wrapped around one another like the strands of a cable. As the name suggests, they are intermediate in size. Actin filaments are smallest and microtubules are largest. Intermediate filaments are important in maintaining the cell’s shape, providing mechanical support; preventing excessive stretching, and supporting other organelles. For example, some intermediate filaments support the plasma membrane and others support the nuclear membrane. Skin cells contain intermediate filaments that provide mechanical strength. They also function to attach cells together (desmosomes)....
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This note was uploaded on 11/10/2011 for the course BIOLOGY bi 101 taught by Professor - during the Fall '10 term at Montgomery.

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