BIOSC-139 Lecture Notes - Lecture 15: Keratin, Mitochondrion, Microtubule
26 Aug 2020
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Document Summary
Endomembrane system: overall function, produce, degrade, store, and export biological molecules, degrade potentially harmful substances, includes er, golgi apparatus, secretory vesicles, lysosomes, nuclear and plasma membranes. Cytoskeleton: elaborate series of rods throughout cytosol; proteins link rods to other cell structures, three types, microfilaments, intermediate filaments, microtubules. Intermediate filaments: tough, insoluble, ropelike protein fibers, composed of tetramer fibrils, resist pulling forces on cell; attach to desmosomes, e. g. , neurofilaments in nerve cells; keratin filaments in epithelial cells. Motor proteins: protein complexes that function in motility (e. g. , movement of organelles and contraction, powered by atp. Centrosome and centrioles: "cell center" near nucleus, generates microtubules; organizes mitotic spindle, contains paired centrioles, barrel-shaped organelles formed by microtubules, centrioles form basis of cilia and flagella. Cellular extensions: cilia and flagella, whiplike, motile extensions on surfaces of certain cells, contain microtubules and motor molecules, cilia move substances across cell surfaces, longer flagella propel whole cells (tail of sperm)
