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Cells

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					       Cells
Why are cells small?
                    Cell Theory
   Cells are the fundamental units of
    life.
   All living organisms are composed of
    cells.
   All cells come from preexisting cells.
                   Size of cells
   Are elephant cells bigger than mouse
    cells? Why or why not?
Surface area to volume ration and cell size

     Cell size is limited by the surface area
      to volume ratio
     As an object increases in volume, so
      does it’s surface area but not at the
      same rate.
Biological significance
   Cell volume determines amount of activity in a given
    amount of time.

   The surface area determines the amount of material
    that can be imported into the cell (nutrients etc.)
    from the extracellular environment and how much
    waste or products can be exported from the
    intracellular space to the extracellular space.

   Draw a diagram to illustrate intracellular space,
    extracellular space/environment
   Cells must maintain a large surface area to volume
    ratio to function

   This explains why large animals have many small
    cells rather than a few large ones
Task – lab

				
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posted:4/23/2011
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