CELLS

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CELLS
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17th Century
Invention of the microscope opened up the world
of tiny objects, like cells, that could not be
seen with the unaided eye.
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Robert Hooke
1665
Cork cells
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fish red blood cells
1702
van Leeuwenhoek
1683
bacteria
pond water
1632 - 1723
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19th Century
Cellular nature of biological materials begin to
receive attention.
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1824
Dutrochet
1831
Brown
All living things are made of cells.
Discovered the nucleus in cells.
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Cell Theory
Schleiden
1838
Schwann
1839
All plants are made of cells.
All animals are made of cells.
Father of Botany
Father of Zoology
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Virchow
Purkinje
1855
1839
Cells can only come from preexisting cells.
Coined the term protoplasm.
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Schultze
Dujardin
1861
1860's
Protoplasm is the physical basis of life.
Recognized one-celled organisms.
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BASIC IDEAS OF THE CELL THEORY

• All organisms are made of one or more cells.
• Cells are the basic unit of structure and
  function in all living things.
• New cells arise only from other living cells by
  the process of cell division.

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By the end of the 19th Century . . .
Biologists had discovered many of the structures
that lie within the cell. They were also able
to describe the events of cell division. Our
knowledge of cell structures took a giant
step forward in the 1950s when the light
microscope was replaced by the electron
microscope. The electron microscope has much
greater resolution than the light microscope.
Today, our most powerful EMs can detect
individual atoms. This high resolution has
allowed biologists to explore cellular
ultrastructure, the complex internal anatomy of
the cell.