Cellular Membranes and Surfaces

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Cellular Membranes and Surfaces

• Source
• Content info. Campbell, N. 1993 Biology.
• Pictures Raven, P. and G. Johnson 1992 Biology

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CELL WALLS

• Structure present in the cells of prokaryotes,
  fungi, plants and some protists
• Protects, maintains shape, prevents excessive
  uptake of water.
• Help support the plant against gravity.
• Plant cell walls are thicker than the cell
  membrane (from 0.1 to several um)
• Composition varies from species to species, from
  cell to cell.

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Cell Wall Composition

• Fibers made up of polysaccharide cellulose are
  embedded in a matrix of other polysaccharides and
  protein (See fig. 5.10 text). This arrangement of
  strong fibers surrounded by an amorphous matrix
  is the same basic architectural design found in
  steel-reinforced concrete and fiberglass.
  (Campbell, 1993)

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Glycocalyx

• Many animal cells have a fuzzy coat called
  glycolcayx
• The glycocalyx is made up of a sticky
  oligosaccharide that attach by covalent bonds to
  both the proteins and lipids of the plasma
  membrane.
• It provides strength to the cell surface and
  helps glue cells together.
• The oligosaccharides contribute to cell-cell
  recognition.

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Cell membraneThe fluid-mosaic model

• Study the following diagram and the information
  in your textbook (p. 152) and then explain the
  following

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• Explain the reason and importance of thefluid
  quality of the cell membrane.
• Explain why membranes are mosaics of structure
  and function.
• Describe the benefits of the amphipathic nature
  of the cell membrane
• Define passive transport, osmosis and diffusion,
  hypotonic, isotonic, hypertonic
• Explain the role of the cell membrane in
  reference to osmosis and diffusion
• The following diagrams comes from Raven, Peter
  Biology (class Textbook)

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• Active Transport Pumps

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Classwork

• Draw and describe the role of the cell membrane
  components.
• Find info. about the Fluid Mosaic Model of the
  Cell Membrane
• History
• Description of the membrane