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CYTOSKELETON AND EXTRACELLULAR MATRIXBlock 5 Erik Kessler, Michael O’Brien, Bryan Richman
• Meshwork of fine fibers within the cell
• Made up of three types of fibers
– Microfilaments, Intermediate Filaments, and Microtubules
• Gives the cell some structural support
• Plays a role in cell movement
– Movement of organelles, and cell itself
– Needed for muscle contraction
• Regulates cellular activity
CYTOSKELETON
Structure:
Function:
More in textbook pg.64
• Solid rod made mostly of the globular protein actin
• Double twisted chain that is 5-9 nm in diameter
• Changes shape by moving subunits from the end to the front
– This can change cell shape and make it move ex.
Amoeba
• Can interact with myosin to contract muscles
• Allows a dividing cell (cytokinesis) to pinch off
into two cells
MICROFILAMENTS
Structure:
Function:
More in textbook pg.64
Globular proteins are hydrophilic
• Rope-like structure
• Made of fibrous protein
• 8-11 nm in diameter
• Made of subunits
– monomer - rod connecting amino head to carboxyl tail
– dimer - two monomers combine
– tetramer - two dimers combined
– tetramers combine into sheets which role up into its rope
shape
INTERMEDIATE FILAMENTS
Structure:
More in textbook pg.64
Fibrous proteins are hydrophobic
• Keep organelles in place and holds the cell structure
– ex. Hold nucleus in place
• Can assemble and disassemble through phosphorylation
with serine
• Can bind with different proteins to improve stability or
create attachment sites for protein assemblies
– ex. actin filaments (microfilaments), microtubules
• Help to attach chromosomes to nuclear membrane
INTERMEDIATE FILAMENTS
Function:
More in textbook pg.64
• Made of globular proteins
• 20-25 nm in diameter
• Act as track for organelle movement through cytoplasm
– ex. lysosomes move along microtubules to reach vacuole,
also support and move cilia and flagella
• Guide chromosomes when cells divide
• Move by adding tubulin to one end and losing them on the
other
MICROTUBULES
Structure:
Function:
More in textbook pg.64And watch the cilia and flagella PowerPoint for more on their function
• Sticky layer of glycoproteins
• Made of: collagen and elastin (structural proteins), fibrillin and
laminin (specialized proteins)
• Holds animal cells together in tissues
• Protects and supports cells
• Regulates cell behavior
• Gives strength, protection, and support to soft parts of the body
(cartilage, etc.)
EXTRACELLULAR MATRIX
Structure:
Function:
More in textbook pg.66
• Adjacent cells in animal tissues are connected by cell junctions
• Regulates what comes into the cell
• Tight Junction: Binds cells together and forms a leak proof sheet
– Prevents passage of molecules through the space between cells
• Anchoring Junction: Attach cells to each other while still allowing material to
pass in the area between the cells
• Communicating Junction: Channels allowing water, small molecules, and ions
to flow between adjacent cells- cells can communicate
with electrical/ chemical signals
CELL JUNCTIONS
Types:
Function:
More in textbook pg.66
Mitchell, and Reece. "Chapter 4: A Tour of the Cell." Biology: Concepts and Connections. By Campell. 3rd ed. San Francisco: Benjamin/Cummings, 2000. 64-66. Print.
Digital image. Http://academic.brooklyn.cuny.edu. Web. 26 Nov. 2010. <http://academic.brooklyn.cuny.edu/biology/bio4fv/page/actin1063.JPG>.Digital image. Http://academic.brooklyn.cuny.edu. Web. 26 Nov. 2010. <http://academic.brooklyn.cuny.edu/biology/bio4fv/page/intermiediate-fil1063.JPG>.Digital image. Http://www.bscb.org. Web. 26 Nov. 2010. <http://www.bscb.org/softcell/images/mp_tripple.gif>.Digital image. Web. 26 Nov. 2010. <http://219.221.200.61/ywwy/zbsw(E)/pic/ech4-1.jpg>."Cytoskeleton." ISCID - International Society for Complexity Information and Design. Web. 23 Nov. 2010. <http://www.iscid.org/encyclopedia/Cytoskeleton>. "Cytoskeleton Tutorial." The Biology Project. 2004. Web. 23 Nov. 2010. <http://www.biology.arizona.edu/cell_bio/tutorials/cytoskeleton/page1.html>."Intermediate Filaments." Cell Biology and Cytochemistry. Web. 23 Nov. 2010. <http://www.cytochemistry.net/cell-biology/intermediate_filaments.htm>. "Microtubules." Cell Biology and Cytochemistry. Web. 27 Nov. 2010. <http://www.cytochemistry.net/cell-biology/microtub.htm>. "Microtubules." Rensselaer Polytechnic Institute (RPI) :: Architecture, Business, Engineering, IT, Humanities, Science. Web. 23 Nov. 2010. <http://rpi.edu/dept/bcbp/molbiochem/MBWeb/mb2/part1/microtub.htm>. "Molecular Expressions Cell Biology: Intermediate Filaments." Molecular Expressions: Images from the Microscope. Web. 27 Nov. 2010. <http://micro.magnet.fsu.edu/cells/intermediatefilaments/intermediatefilaments.html>"Cytoskeleton Tutorial." The Biology Project. Web. 30 Nov. 2010. <http://www.biology.arizona.edu/cell_bio/tutorials/cytoskeleton/page1.html>.<http://rpi.edu/dept/bcbp/molbiochem/MBWeb/mb2/part1/microtub.htm>. "Molecular Expressions Cell Biology: Intermediate Filaments." Molecular Expressions: Images from the Microscope. Web. 27 Nov. 2010. <http://micro.magnet.fsu.edu/cells/intermediatefilaments/intermediatefilaments.html>."The Extracellular Matrix." 12 Apr. 2009. Web. 1 Dec. 2010. <http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/ECM.html>.
"Microtubules." Cell Biology and Cytochemistry. Web. 27 Nov. 2010. <http://www.cytochemistry.net/cell-biology/microtub.htm>. "Microtubules." Rensselaer Polytechnic Institute (RPI) :: Architecture, Business, Engineering, IT, Humanities, Science. Web. 23 Nov. 2010.
"Junctions Between Cells." 10 Oct. 2010. Web. 1 Dec. 2010. <http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/J/Junctions.html>.
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