Cell Lecture #1

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