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Cell Theory and the Cell

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Cell Theory and the Cell Powered By Docstoc
					     History of
  Cell Theory &
Cellular Structures
       The Discovery of Cells
•   Anton van Leeuwenhoek
•   Used a simple microscope
•   He was the first person to
    use a microscope to study
    nature.
•   He was the first to see tiny living
    organisms in a drop of water.
      The Discovery of Cells
•   Wanted to know why corks float.
•   Looked at cork
    (plant) cells.
•   Looked like monk’s
    cells.
•   Term “cell” was coined in 1665 by
    Robert Hooke when he looked at a slice
    of dried cork.
       The Discovery of Cells
•   Mid 1800’s Frenchman named Dujardin
    found what we now call protoplasm. It is
    the living material within a cell.
•   About the same time an English scientist
             named Robert Brown
             observed the interior of the cell.
      The Discovery of Cells
•   Using a very simple microscope, he
    observed an opaque spot
    in a plant which
    he named the nucleus.
           The Cell Theory
•   Contributors to Cell Theory
•   Matthias Schleiden-All plants are
    are made of cells.

             Theodor Schwann-All animals
             are made of cells.
           The Cell Theory
•   Rudolph Virchow
•   Proposed that all cell come from existing
    cells.
•   Completing the cell
     theory.
            Cell Theory

1. All living things are comprised of
   cells.
2. Cells are the smallest “living” unit in
   an organisms.
3. Cells come from previously existing
   cells.
             Cell Diversity
• Lots of shapes and sizes
      Two Categories of Cells
• Biologists divide cells into two categories:
   eukaryotes and prokaryotes.
• The cells of eukaryotes have a nucleus, but
  the cells of prokaryotes do not.
• Bacteria are prokaryotes.
Prokaryotes
Eukaryotes
        Cell Organization

The cell includes two basic parts:
1. Cell Membrane-a thin, flexible barrier
   around the cell. Plants have also have a
   cell wall.
2. Cytoplasm-fluid material inside the
   cell membrane. Many cell organelles
   (cell organs) found in cytoplasm.
           Cell Membrane
• The cell membrane forms the outside
  boundary that separates the cell from its
  environment.
• Main function is to control what substances
  come into and out of a cell.
• Acts like a window screen.
Cell Membrane
                 Nucleus
• Control center of cell
• Acts like a
  “Brain”
• Contains
  the genetic
  material.
  Organelles in Cytoplasm
Endoplasmic reticulum (ER)
A network of membrane-bound tunnels
that carry proteins and other materials.
              Ribosomes
• Particles attached to ER are ribosomes.
• Ribosomes function as factories to produce
  proteins.
           Golgi Apparatus
• Flattened sacs and tubes
• Involved in packaging and secretion of
  proteins
• Acts like
  the cells
“mailroom”
            Mitochondria
• Bean shaped
• Use energy from food to make high-energy
  that the cell
  can use for
  growth,
  movement and
  development.
           Other organelles
• Chloroplasts-Found in plant cells
  Capture energy from sunlight to produce
  food
• Vacuoles-storage area for the cell
• Lysosome-small round structures that
  contain chemicals that break down food
  particles and old cells, “Clean up crew”

				
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posted:5/12/2012
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