1. Cell Lecture #1 What Are Cells? History of Cells

2. What is a Cell?  A cell is the basic unit of structure and function in living things.  Invention of microscope made seeing cells possible

3. History of Cell Discovery Robert Hooke gets credit for discovering cells by looking at cork - he thought they looked like “prison cells”

4. Anton van Leeuwenhoek  This Dutch scientist discovered little things swimming in pond water which he called “animalcules” (little animals) with microscopes he made himself

5. Three parts to the Cell Theory  1.All living things are made of cells  2.All cells come from other cells  3. The cell is the basic unit of structure and function in living things

6. Early Cell Scientists  1.Matthias Schleiden discovered that all plants were made of cells in 1835  2. Theodore Schwann discovered that all animals were made of cells in 1836

7. Early Cell Scientists (cont)  3. Rudy Virchow discovered that all cells come from other cells in 1855; His rule - Omnis cellula e cellula ("every cell originates from another cell")

8. Main Types of Microscopes  Light microscopes bend light rays through convex lenses. They are powerful because you multiply the powers of each lens to get total magnification

9. Electron Microscopes  Electron Microscopes use a focused beam of electrons instead of light allowing for much increased magnification. Unfortunately it kills the specimen if it is alive.

10. Scanning Electron Microscope Pics