1. Cells and Cell Theory

2. Leeuwenhoek • 1673-1723 Anton van Leeuwenhoek
described livemicroorganisms
observed in teethscrapings, rain water,and peppercorninfusions.

3. The First Observations
• 1665 Robert Hooke
– reported that living
things were
composed of little
boxes or cells.

4. Schleiden & Schwann Development of the CELLTHEORY
• Matthias Schleiden (1838) – using a microscope proposed that all plants are composed of cells
• Theodor Schwann (1839) – using a microscopeproposed that all animals are composed of cells
• Together they stated:
– Cells are the elementary particle of all livingorganisms
– All cells are alive – independent to the organisms to which they belong

5. Virchow • 1858, Rudolf Virchow
said cells arise from preexisting cells.

6. Cell Theory Cell Theory * • All living things are composed of one or
more cells
• Cells are the basic units of structure
and function in an organism
• Cells come only from the reproduction
of preexisting cells
* Named for the Monk prayer cells

7. Cells Eukaryotic versus Prokaryotic Cells
• Prokaryotic - Cells lacking a nucleus.
• Eukrayotic - Cells containing a nucleus.
– Organelles - Membrane-bound bodies found within eukaryotic cells.

8. Types of Cells Two Basic Types of Cells • Prokaryotes:
– prounounced: pro-carry-oats
• Eukaryotes
– Proun: you-carry-oats

9. Eukaryotes Eukaryotes
• Larger more complex cells that make up most familiar life forms:
plants, animals, fungi, algae
• Surrounded by a cell
membrane made of
lipids

10. Prokaryotes Smaller No true nucleus – loose genetic material
Includes Archaea & Bacteria