1. T HE H ISTORY OF THE C ELL T HEORY

2. R OBERT H OOKE The invention of the microscope made possible the observation of the world that was not visible to the unaided human eye. The cell was first discovered and named by Robert Hooke in 1665. While looking at a sample of cork under the microscope, he thought it looked similar small rooms which monks inhabited called cellula. He named the small structures he saw cells.

3. A NTONIE VAN L EEUWENHOEK ley-vuhn-hook Leeuwenhoek was known as the “Father of Microscopy” for his invention of the first practical microscope. He was also the first man to witness a live cell under a microscope in 1674. He saw and described animalcules (little animals) in pond water and even bacteria in his own mouth.

4. M ATTHIAS S CHLEIDEN Schleiden was a professor of Botany who in 1838 drew the conclusion that all plants are made from cells and also recognized the importance of the nucleus in cell division.

5. T HEODOR S CHWANN 1839, Schwann (a cell biologist and physiologist) applied Schleiden’s plant theory to animals and stated that all animals are composed of cells.

6. S CHLEIDEN AND S CHWANN ’ S C ELL T HEORY The cell is the unit of structure, physiology, and organization in living things. The cell retains a dual existence as a distinct entity and a building block in the construction of organisms. Cells form by free-cell formation, similar to the formation of crystals (spontaneous generation).

7. R UDOLPH V IRCHOW In 1858 he corrected the mistake made by Schwann and added to it. to develop: The Modern Cell Theory *All known living things are made up of cells. *The cell is structural & functional unit of all living things. *All cells come from pre-existing cells by division. (Spontaneous Generation does not occur). Cells contains hereditary information which is passed from cell to cell during cell division. All cells are basically the same in chemical composition. All energy flow (metabolism & biochemistry) of life occurs within cells.