Cell Theory

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Cell Theory
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Ancient cells

• First cell-about 3.5 billion years ago
• Different from cells today
• Over time, the cell became more complex and able
  to do more things
• Most cells are microscopic and have even smaller
  parts inside called organelles which means
  small organs

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Cell Theory Scientists

• 1665 Robert Hooke looked at cork under the
  microscope and saw small rooms he called cells.
  (were actually cell walls)

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• 1665 Anton van Leeuwenhoek-looked at blood,
  water, other materials. First person to see
  living cells. He called them animalcules.
• Some of these were actually bacteria
• Bacteria Sperm

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Anton van Leeuwenhoeks Microscope
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• Over the next 200 years, microscope technology
  greatly improved.
• Mid-1800s
• Mathais Schleiden-looked at plant parts and
  determined all plants are made of cells
• Theodor Schwann-looked at animal parts
• and determined all animals are
• made of cells
• Rudolph Virchow-experimented to see if living
  cells could arise from dead cells

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The Cell Theory

• The discoveries of all 5 scientists led to the
  cell theory which is stated as
• All living things are made of cells
• Cells are the basic units of structure and
  function in living things
• Living cells come only from other living cells