Chapter 7. The Cell: Cytoskeleton - Pearland High School
Chapter 7. The Cell: Cytoskeleton AP Biology 2005-2006 Cytoskeleton Function structural support maintains shape of cell
provides anchorage for organelles motility cell locomotion cilia, flagella, etc. regulation organizes structures & activities of cell AP Biology
2005-2006 Cytoskeleton Structure network of fibers extending throughout cytoplasm 3 main protein fibers microtubules microfilaments intermediate filaments Its a matter of size
AP Biology 2005-2006 AP Biology 2005-2006 Evolutionary perspective Proteins that make up the fibers are very similar in all living things from bacteria to humans tubulin (all cells)
actin (eukaryote cells) Means that they are both ancient and essential for life AP Biology 2005-2006 Microtubules Structure thickest fibers hollow rods about 25nm in diameter
constructed of protein, tubulin grow or shrink as more tubulin molecules are added or removed AP Biology 2005-2006 Microtubules Function
structural support & cell movement move chromosomes during cell division centrioles tracks that guide motor proteins carrying organelles to their destination motor proteins: myosin & dynein motility cilia flagella AP Biology 2005-2006
Centrioles Cell division AP Biology in animal cells, pair of centrioles organize microtubules guiding chromosomes in cell division 2005-2006 Cilia & flagella Extensions of eukaryotic cytoskeleton
Cilia = numerous & short (hair-like) Flagella = 1-2/cell & longer (whip-like) move unicellular & small multicellular organisms by propelling water past them cilia sweep mucus & debris from lungs flagellum of sperm cells AP Biology 2005-2006 Cilia Oar-like movement
alternating power & recovery strokes generate force perpendicular to cilias axis AP Biology 2005-2006 Flagella undulatory movement AP Biology
force generated parallel to flagellums axis 2005-2006 Cilia & Flagella Structure remember 9+2! 9 pairs of microtubules around 2 single microtubules in center bending of cilia & flagella is driven
by motor protein dynein AP Biology requires 2005-2006 ATP AP Biology 2005-2006 Microfilaments (actin filaments) Structure
thinnest class of fibers solid rods of protein, actin twisted double chain of actin subunits about 7nm in diameter Function
AP Biology 3-D network inside cell membrane in muscle cells, actin filaments interact with myosin filaments to create muscle contraction 2005-2006 Lets go to the video tape! (play movie here) Microfilaments (actin filaments) Dynamic process
actin filaments constantly form & dissolve making the cytoplasm liquid or stiff during movement movement of Amoeba cytoplasmic streaming in plant cells speeds distribution of materials AP Biology 2005-2006 Intermediate filaments Structure
specialized for bearing tension built from keratin proteins same protein as hair intermediate in size 8-12nm Function
hold things in place inside cell more permanent fixtures of cytoskeleton reinforce cell shape & fix organelle location nucleus is held in place by a AP Biology network of intermediate filaments 2005-2006
Microfilaments thinnest internal movements within cell actin, myosin Intermediate filaments
AP Biology intermediate more permanent fixtures keratin 2005-2006 AP Biology 2005-2006 AP Biology
2005-2006 Cell Junctions Where cells touch each other AP Biology 2005-2006 Plant cell wall Structure cellulose primary cell wall secondary cell wall
middle lamella = sticky polysaccharides AP Biology 2005-2006 Intercellular junctions Plant cells plasmodesmata channels allowing cytosol to pass between cells
plasmodesmata AP Biology 2005-2006 Animal cell surface Extracellular matrix collagen fibers in network of glycoproteins support adhesion
movement regulation AP Biology 2005-2006 Intercellular junctions in animals AP Biology 2005-2006 Intercellular junctions Animal cells
tight junctions membranes of adjacent cells fused forming barrier between cells forces material through cell membrane gap junctions communicating junctions allow cytoplasmic movement between adjacent cells
desmosomes anchoring junctions fasten cells together in strong sheets AP Biology 2005-2006 AP Biology 2005-2006 AP Biology
2005-2006 A cell is a living unit greater than the sum of its parts AP Biology 2005-2006 And now for some Stupid Penguin Tricks. Any Questions?? AP Biology
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