tailieunhanh - Lecture Biochemistry (2/e): Chapter 17 - Reginald Garrett, Charles Grisham
Movement is an intrinsic property associated with all living cells, molecules undergo coordinated and organized movements, and cells themselves may move across a surface. At the tissue level,muscle contraction allows higher organisms to carry out and control crucial internal functions, such as peristalsis in the gut and the beating of the heart. Muscle contraction also enables the organism to perform organized and sophisticated movements, such as walking, running, flying, and swimming. | Chapter 17 Molecular Motors to accompany Biochemistry, 2/e by Reginald Garrett and Charles Grisham All rights reserved. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt Brace & Company, 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 1 Outline Molecular Motors Microtubules and Their Motors Skeletal Muscle Myosin and Muscle Contraction A Proton Gradient Drives the Rotation of Baterial Flagella 2 Tubulin and Microtubules Fundamental components of the eukaryotic cytoskeleton Microtubules are hollow, cylindrical polymers made from tubulin dimers 13 tubulin monomers per turn Dimers add to the "plus" end and dissociate from the "minus" end as in Figure Microtubules are the basic components of the cytoskeleton and of cilia and flagella Cilia wave; flagella rotate - ATP drives both! 3 Microtubules in Cilia & Flagella MTs are the fundamental structural unit in cilia and flagella (see axoneme structure, Fig ) Dynein proteins walk or slide along MTs to cause bending of one MT relative to another Dynein movement is ATP-driven See Figures and 4 Microtubules Highways for "molecular motors" MTs also mediate motion of organelles and vesicles through the cell In axons, dyneins move organelles + to -, ., toward the nucleus Kinesins move organelles - to + , ., away from the nucleus See Figure and compare (a) and (b) 5 Polymerization Inhibitors Therapeutic agents for gout and cancer Colchicine, from autumn crocus, inhibits MT polymerization, mitosis and also white cell movement - it is a remedy for gout and an inducer of larger, healthier plants Vinblastine, vincristine also inhibit MT polymerization - anticancer agents Taxol, from yew tree bark, stimulates polymerization, stabilizes microtubules and inhibits tumor growth, (esp. breast and ovarian) 6 Morphology of Muscle Four types: skeletal, cardiac, smooth and myoepithelial cells A fiber bundle contains hundreds . | Chapter 17 Molecular Motors to accompany Biochemistry, 2/e by Reginald Garrett and Charles Grisham All rights reserved. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt Brace & Company, 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 1 Outline Molecular Motors Microtubules and Their Motors Skeletal Muscle Myosin and Muscle Contraction A Proton Gradient Drives the Rotation of Baterial Flagella 2 Tubulin and Microtubules Fundamental components of the eukaryotic cytoskeleton Microtubules are hollow, cylindrical polymers made from tubulin dimers 13 tubulin monomers per turn Dimers add to the "plus" end and dissociate from the "minus" end as in Figure Microtubules are the basic components of the cytoskeleton and of cilia and flagella Cilia wave; flagella rotate - ATP drives both! 3 Microtubules in Cilia & Flagella MTs are the fundamental structural unit in cilia and flagella (see axoneme .
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