1. Cell History

2. History of the Cell O Robert Hooke: Discovered cells O 1665 –Made a simple microscope and looked at a piece of cork (dead cells of oak bark) O Observed small box-like structures that reminded him of the cells that monks lived in O Named them cellulae O (Latin, cell = small room) O Origin of the term cell

3. History of the Cell O Anton Van Leeuwenhoek: First to view live cells O Viewed living organisms in pond water and milk O Called them “Wee Beasties”

4. Cell Theory O Developed by Schledin, Schwann, and Virchow O Matthias Schleiden: Studied plant tissues and concluded that all plants are composed of cells O Theodor Schwann: Found that all animal tissues are composed of cells O Rudolph Virchow: Proposed that all cells come from preexisting cells The observations of Schledin, Schwann, and Virchow led to the cell theory …

5. Cell Theory O All living organisms are composed of one or more cells. O Cells are the basic structure of all living organisms. O Cells arise only from preexisting cells, with cells passing copies of their genetic material on to their daughter cells.

6. Microscopes and Cells O The discovery of cells and the development of cell theory would not have been possible without microscopes. O Developments in microscope technology have enabled scientists to study cells in detail.

7. Microscopes and Cells O Compound Light Microscopes O Uses a series of lenses and light to produce a magnified image O Each lens magnifies the image of the previous lens to produce the total magnification (for example 10 x 10 = 100 times) O Stains can be used to allow cells to be seen more easily

8. Microscopes and Cells O Electron Microscopes O Use magnets to aim a beam of electrons at thin slices of cells O Transmission – shows interior features O Scanning – shows exterior features

9. Learning Check 1. Who was the first person to see cells? 1. What technological development allowed scientists to see cells? 1. What type of microscope did you use in class? 1. Use your notes to complete the cell theory graphic organizer.