1. The Microscope
And the cell theory

2. Robert Hooke (1665) First discovered cells
He looked at a slice of cork under a “primitive” microscope

3. The cells looked like honeycomb shaped structures
Hooke used the word “cell” to describe those shapes

4. Anton van Leeuwenhoek
Observed living blood cells, and bacteria a few years later
Leeuwenhoek is called the “father of microscopy”

5. A few years later, Robert Brown , looked at plant cells and described a dark sphere at their center, the nucleus

6. Cell Theory 1) All living things are composed of cells.
2) Cells are the smallest unit of life.
3) All cells come from pre-existing cells.

7. Brain Pop
Microscopes
Cell Structure

8. Compound Microscopes

9. An important development to microscopes was adding the second lens
The eye piece (occular lens) magnifies the image 10x
By adding a second lens that also magnifies by 10x the total magnification becomes 100x (10 x 10)
By how much is an object magnified when viewing it under high power (40 x)?

10. Transmission Electron Microscopes

11. Today TEMs can magnify objects by 2 000 000 times
Instead of light, TEMs use beams of electrons to magnify images
TEM’s have two limitations
1. They can’t magnify specimens that contain many layers of cells
2. They can only magnify dead cells

12. Scanning Electron Microscopes

13. Can magnify thick specimens Provide a 3-D image Limitations
Cannot magnify as much as TEMs
Resolution (focus) is not as good as TEMs

14. Proper Use of a Microscope
Always carry with one hand on the arm and one hand on the base
Always begin on low power
Never use coarse adjustment on high power

16. Bacteria
Bacteria, Germs and viruses are some things that we can use microscopes to investigate
Bacteria are one celled microorganism
They can be beneficial- yogurt
They can be harmful- tetanus and pneumonia
Bacteria

17. Cell City- Project
From your knowledge of cell organelles and the descriptions on the worksheet, match up the cells that do the correct function.
Today you just have to correctly match up the worksheet
Tomorrow we will be creating “Cell City Maps” on Art Paper
This will help you remember the different parts of each organelle
Two people to a group
Bring Markers and Pencil Crayons !