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The Cell Cytoskeleton Chapter 17. Watch this animation http://multimedia.mcb.harvard.edu/ anim_innerlife.html. The Inner Life of Cells. Questions in this chapter you should be able to answer: Chapter 17: 1 - 11, 13 - 23. The Cell Cytoskeleton What are the 3 primary types
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The Cell Cytoskeleton Chapter 17 Watch this animation http://multimedia.mcb.harvard.edu/ anim_innerlife.html The Inner Life of Cells Questions in this chapter you should be able to answer: Chapter 17: 1 - 11, 13 - 23 The Cell Cytoskeleton
The Cell Cytoskeleton What are the 3 primary types of cytoskeletal proteins? Intermediate filaments -- resist mechanical stress Microtubules -- cytoplasmic transport -- axoneme movement -- chomosome movement Actin filaments -- membrane contraction -- muscle cells -- cytokinesis The Cell Cytoskeleton
What is the structure of intermediate filaments, and how does this relate to their function? Cable-like arrangement Extended molecular interactions Binding to desmosomes Distribution Interm filaments The Cell Cytoskeleton
What is the fundamental structure of microtubules? Alpha and beta tubulin subunits 13 member ring Why do MTs have polarity? ‘MT Organizing Center’ Why are MTs said to display ‘Dynamic Instability’? 17.2 Dynamic Instability The Cell Cytoskeleton
What is the mechanism of MT growth and retraction? Binding, hydrolysis and release of GTP ‘Capping’ at cell membrane 17.4 MT with EBI cap Question 17-3, p 583 How would a change in [tubulin] affect MT dynamics? ..if only GDP were present? … or a nonhydrolizable GTP analog? The Cell Cytoskeleton
How do MTs facilitate cytoplasmic transport? Motor proteins kInesin & dynein 17.5 Kinesin walking 17.6 Organelle Movement The Cell Cytoskeleton
What is the structure and movement of an axoneme? Cilia & flagella “9 + 2 Structure” Living cell video The Cell Cytoskeleton
Axoneme mutations and Immotile Cilia Syndrome Diagnosis Symptoms; respiratory infection; situs inversus, flagella and embryonic development - IDA - ODA - IDA Morillas HN, Zariwala M, Knowles MR. 2007. Genetic Causes of Bronchiectasis: Primary Ciliary Dyskinesia.Respiration 2007;74:252-263 The Cell Cytoskeleton
What is the distribution and structure of actin filaments? The Cell Cytoskeleton
How are actin filaments organized in the cytoplasm? The cell cortex Actin binding proteins The Cell Cytoskeleton
How does actin mediate cell movements? Cell crawling What are Lamellipodia and Filopodia? Membrane ruffling 17.9 projectile bacteria (Listeria) Question 17-7 Pg 598 The Cell Cytoskeleton
Actin, myosin and muscle contraction Some basic anatomy. . . Muscle are bundles of muscle cells Muscle cells contain myofibrils Sarcomere is contractile unit of myofibril The Cell Cytoskeleton
What is the structure of a myosin thick filament? How are actin and myosin arranged within a sarcomere? The Cell Cytoskeleton
What happens to sarcomere during contraction? How does myosin interact with actin filament? The Cell Cytoskeleton
How does the sliding filament model explain sarcomere contraction? Myosin is attached ATP binds Myosin head detaches ATP hydrolyzed Myosin Head position cocks and Loosely binds to actin Pi is released Myosin head tightly binds to actin Powerstroke ADP released Myosin remains attached 17.7 myosin The Cell Cytoskeleton
How is muscle contraction triggered? Motor neuron & action potential Sarcoplasmic reticulum T-tubules Ca++ release 17.8 sarcomere The Cell Cytoskeleton
How does Ca++ trigger the muscle contraction? The tropomyosin / troponin complex Actin myosin animation The Cell Cytoskeleton