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29 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Cytoskeleton (definition)
3 types of protein filaments |
an intricate network of protein filaments that extends throughout the cytoplasm
573, see also glossary definition 3 types of protein filaments: 1) Actin filaments 2) Intermediate filaments 3) Microtubules |
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The Cytoskeleton enables the cell to:
-Adopt a variety of _____ -Organize the _______ in the _____ of the cell -Interact ________ with the _________ -Carry out coordinated ________ -helps support the large volume of ______ -provides machinery for in___cellular movements |
-Adopt a variety of _shapes_
-Organize the _components_ in the _interior_ of the cell -Interact _mechanically_ with the _environment_ -Carry out coordinated _movements_ -helps support the large volume of _cytoplasm_ -provides machinery for intracellular movements (transport of organelles, segregation of chromosomes during mitosis, cytokinesis, transport between organelles) 573/notes |
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Some examples of INTRAcellular movements governed by the cytoskeleton
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-transport of organelles
-transport (of various stuff) between organelles -segregation of chromosomes during mitosis -pinching apart of animal cells at cell division (cytokinesis) 573/notes |
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do bacterial (prokaryotic) cells have cytoskeletons?
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NO
573 |
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Intermediate filaments:
-physical description -diameter -made of _________; subunit |
-ropelike fibers
-10 nm -made of intermediate filament proteins. The subunits of intermediate filaments (the strands) are elongated fibrous proteins |
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Main purpose of intermediate filaments
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to enable cells to withstand the mechanical stress that occurs when cells are stretched
574-5 (resists tension applied to the cell from outside) |
-Have great tensile strength
-Toughest & most durable of 3 |
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Where are intermediate filaments found?
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One type forms a meshwork called the NUCLEAR LAMINA
Other types extend across the cytoplasm See 17-2, 575 |
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4 classes of intermediate filaments
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1) keratins
2) vimentin & vimentin-related 3) neurofilaments 4) nuclear lamins 17-6 577 |
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Many intermediate filaments are further stabilized and reinforced by _______ _____ that cross-link the filament bundles in strong arrays
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accessory proteins
(such as plectin) |
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plectin
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an accessory protein that holds together vimentin filaments (a type of IF) and links them to microtubules, actin filaments, and to adhesive structures in the desmosomes
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desmosome
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specialized cell-cell junction, usually b/t 2 epithelial cells
has dense plaques of protein into which IFs in the 2 cells insert (used to anchor IFs to the PM) |
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Microtubules
-physical description -diameter -made of (subunit) USED FOR: |
-long, hollow cylinders (hollow=tube)
-25nm -subunit=tubulin (a protein) Used to regulate cell shape and control their movements |
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mitotic spindle (what it does)
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provides the machinery that will segregate the chromosomes equally into the 2 daughter cells just before a cell divides
Fig. 17-9B |
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centrosome
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centrally located organelle of animal cells that is the primary MTOC
-acts as the spindle pole during mitosis -in animal cells it contains a pair of centrioles glossary/580 |
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dynamic instability
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the property shown by MTs of growing & shrinking repeatedly through the addition & loss of tubulin from their exposed (+) ends
17-12, 581 |
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What (process) controls the growth of microtubules?
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GTP hydolysis
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motor protein
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protein that uses energy derived from ATP hydrolysis to propel itself (through conformational changes) along a protein filament or polymeric molecule
examples: myosin, kinesin Glossary, 155-6, 4-44, 4-45, 586 |
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How do motor proteins move?
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they are allosteric and move by transition through conformation changes, one which is coupled to hydrolysis of an ATP molecule bound to the protein
see Figure 4-44 & 4-45 (156. 157) |
allosteric
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2 families of motor proteins that move along cytoplasmic MTs
-& which direction they move in |
1) Kinesins
-move toward the + end of MT -away from centrosome 2) Dyneins -move toward the - end -toward centrosome |
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the globular head of a MT-assoc'd motor protein interacts with _______
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microtubules
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MTs or the cell component to be transported?
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the tail of a MT-assoc'd motor protein interacts with _________
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the cell component to be transported
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MTs or the cell component to be transported?
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Endoplasmic reticulum (ER)
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Labyrinthine, membrane-bounded compartment in the cytoplasm of eukaryotic cells
-where lipids are secreted and membrane proteins are made Function: Forms compartments and vesicles; participates in protein & lipid synthesis (p. 90 of BIO) See hint for more info and index |
These structures are responsible for several specialized functions: Protein translation, folding, and transport of proteins to be used in the cell membrane (e.g., transmembrane receptors and other integral membrane proteins), or to be secreted (exocytosed) from the cell (e.g., digestive enzymes); sequestration of calcium; and production and storage of glycogen, steroids, and other macromolecules.[2] The endoplasmic reticulum is part of the endomembrane system. The basic structure and composition of the ER membrane is similar to the plasma membrane.
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Golgi apparatus
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Membrane-bounded organelle in eukaryotic cells where the proteins and lipids made in the ER are modified and sorted
Function: packages proteins for export from cell; forms secretory vesicles (p. 90 of BIO) See hint for more info and index |
The primary function of the Golgi apparatus is to process and package the macromolecules such as proteins and lipids that are synthesized by the cell. It is particularly important in the processing of proteins for secretion. The Golgi apparatus forms a part of the endomembrane system of eukaryotic cells.
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flagellum
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rives a cell through a fluid medium by its beating
17-26 (591) |
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cilium
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in large #s, cilia drive the movement of fluid over epithelial sheets, as in the lungs
17-25 (590) |
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# of heads & tails, filament the following motor proteins are associated with:
-kinesin -dynein -myosin-I -myosin-II |
-2 heads, 1 tail, MTs
-" " -1 head, 1 tail, AFs -2 heads, 1 (coiled-coil) tail, AFs |
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___-hydrolysis is involved in controlling MT assembly/dissambly
___-hydrolysis is involved in controlling AF assembly/dissambly |
GTP for MTs (17-13, 582)
ATP for AFs (17-31, 594) |
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myosin-I: function
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used to move stuff along AFs
17-38 |
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myosin-II: function
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myosin-II molecules associate together to form "myosin filaments"
-then associates with AFs to form contractile structures |
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