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Cell theory notes
The Cell Theory
• Robert Hooke- (1665) examined a piece of
cork under a microscope and discovered
cells.
• Schleiden (1873) concluded that all plants
are composed of cells and that cells are the
basis of all its functions.
The Cell Theory
• Theodor Schwann- (1839) “concluded that
all animals are composed of cells and that
they are the basis behind all of their
functions”
• Rudolf Virchow- (1858) “stated that all
cells come from other living cells.”
Cell Theory
• 1. All organisms are composed of one or
more cells or cell fragments.
• 2. The cell is the basic unit of structure and
function in organisms
• 3. All cells are produced from other cells.
• Memorize this !!!
Cell Types
• 1. Prokaryotic Cells– Cells that do not have a true nucleus. (they still have
DNA)
– Most are bacteria
– All are unicellular
• 2. Eukaryotic Cells– Cells that contain a membrane bound nucleus and
membrane bound organelles.
– Can be multi or unicellular
– This includes most living things (Plants and animals)
Plant cells vs. Animal cells
• Plant cells (usually brick shaped)
– Have thick cell wall made of cellulose.
– Possess large vacuoles for storage of water.
– Contain chloroplasts (photosynthesis)
• Animal cells (not green)
– Animal cells lack those structures found above.
– Animal cells usually are not brick shaped.