The Cytoskeleton Overview
In 1903, Nikolai K Koltsov proposed cell structures to be determined by a network of tubules he termed as the cytoskeleton. According to Koltsov, the cytoskeleton is a cellular scaffolding or skeleton contained within a cell's cytoplasm. Once thought to be unique to eukaryotes, recent research has identified prokaryotic cells to possess a cytoskeleton as well. Structures such as flagella, cilia and lamellipodia are able to be formulated from the cytoskeleton and play vital roles in both intracellular transport (the movement of vesicles and organelles) and cellular division. Scientists have further categorized the types of cytoskeleton into three subcategories: microfilaments, intermediate filaments, and microtubules.
Microfilaments
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Intermediate Filaments
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Microtubules
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Solid rods composed of two intertwined strands of actin.
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Hollow tubes much like a pipe composed of heterogenous proteins.
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Hollow tubes with walls composed of 13 columns of tubulin protein.
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7nm
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8-10nm
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25nm with 15nm lumen
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F actin and G actin
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5 proteins from the keratin family
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Monomers, alpha tubulin, and beta tubulin
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All eukaryotic cells contain actin, only animal cells contain myosin.
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Almost all eukaryotic cells contain intermediate filaments.
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All eukaryotic cells contain microtubules.
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