Tour of the Cell

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Tour of the Cell

• Part Two

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I. Cytoskeleton

• A. Microtubules
• Hollow Rods
• Tubulin subunits
• Cell division and movement
• Are grown from Centrosome
• B. Microfilaments
• Solid Filaments
• Actin subunits
• Cell Division
• Muscle contraction (with the help of myosin),
  cell movement and shape

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I. Cytoskeleton

• C. Intermediate Filaments
• Only in animal cells of specific tissues
• Mechanically strengthen cell structure or cell
  parts and help maintain shape

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I. Cytoskeleton

• D. Cilia Flagella
• Made of microtubules
• Flagella are larger and typically there is only
  one or two
• Cilia are smaller and they cover a cell
• Microtubules of Cilia and Flagella are covered
  with plasma membrane

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II. Cell Surfaces Junctions

• A. Cell Walls
• Plant cells are covered by a cell wall
• Made of cellulose, very rigid
• Gives support
• Plant cells are able to communicate through
  plamodesma

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II. Cell Surfaces Junctions

• B. Extra Cellular Matrix (ECM)
• Composed mostly of glycoproteins
• Give extra support outside of cell
• Allow for communication between cells
• Makes cells sticky

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II. Cell Surface Junctions

• C. Junctions in animal cells
• 1) Tight membranes of neighboring cells are
  fused (stitching cells together)
• Forces things to pass through the cells of a
  tissue (blood-brain barrier)
• Still allow for spaces between the cells
• 2) Desmosomes (anchoring junctions) fasten
  cells together in sheets
• Similar to tight junctions, but have keratin
  reinforcement
• Prevent shearing, (muscle cells have many of
  these)
• 3) Gap junctions for communication provide
  channels between adjacent cells

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Junctions
Tight Junctions
Desmosomes
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Junctions
Gap Junctions