1. Cell Theory and the Microscope SBI3C0 Ms. Manning

2. Review of the Cell TheoryReview of the Cell Theory  3 statements make up the cell theory: 1. All living things are composed of one or more cells. 2. Cells are the basic structural and functional units of life. 3. All cells arise from the division of other cells.

3. The MicroscopeThe Microscope  There are many different types of microscopes, we will learn about 4 types. 1. The Simple Light Microscope 2. The Compound Microscope 3. The Transmission Electron Microscope (TEM) 4. The Scanning Electron Microscope (SEM)

4. 1. The Simple Light Microscope1. The Simple Light Microscope  Hand held, made of a single lens  Used by 17 th century biologist Anton van Leeuwenhoek

5. 2. The Compound Light Microscope2. The Compound Light Microscope  2 lenses: ocular and objective  Illuminated with a bulb  Total Magnification = ocular x objective  Cannot resolve parts of a specimen closer together than 200 nm

6. 3. Transmission Electron Microscope3. Transmission Electron Microscope  An invisible beam of electrons pass through a very thin specimen  Specimen is coated in plastic and shaved very thin...only dead specimens!  Designed and built in 1937 at U of T  Magnify 5 000 000 x and resolve up to 0.2nm

7. TEM cont’dTEM cont’d

8. 4. Scanning Electron Microscope4. Scanning Electron Microscope  Thicker, whole specimens can be used  Thin stream of electrons scans surface of specimen to produce a 3D image  Less mag and resolution than TEM, but greater contrast and depth  Mag up to 300 000x and resolution of 10nm

9. SEM cont’dSEM cont’d