1. Cell Theory Chapter 7

2. Cell - smallest unit that can carry on all the processes of life 2 types of organisms: 1. Unicellular organism - living thing that consists of only ONE cell Ex: paramecium, bacteria

3. 2. Multicellular organism - living thing that consists of MORE THAN one cell Ex: humans, plants, animals

4. Knowledge of cells began with the invention of the lens in the 1600s and has increased today with the electron microscopes Robert Hooke - 1 st person to view cells under the microscope observed thin slices of cork (plant) saw little empty boxes - called cells Hooke was the 1 st to look!

5. Hooke’s microscope and the cells he saw

6. Anton von Leewenhoek - 1 st person to view living cells in 1675

7. In 1838, Mathias Schleiden stated that ALL PLANTS were made up of cells

8. In 1839, Theodor Schwann stated that ALL ANIMALS were made of cells

9. In 1855, Rudolph Virchow concluded that CELLS COME ONLY FROM EXISITNG CELLS

10. Cell theory All these observations were combined to form the cell theory: 1. All living things are composed of one or more cells. 2. Cells are an organism’s basic unit of structure and function. 3. Cells come only from existing cells.

11. Cells not all cells are the same, but they do have some similarities: all have a cell membrane all will have some DNA (genetic material) all will perform the processes of life

12. there are some cells that have little structures that will perform certain functions for the cell these structures are ORGANELLES they’re like our organs in our bodies there are 2 categories of cells:

13. 1. Prokaryotic cells simplest type of cells no membrane bound organelles no nucleus have cell membrane

14. The only organisms to have prokaryotic cells are bacteria

15. 2. Eukaryotic cells have membrane bound organelles have nucleus usually larger, more complex

16. ALL other organisms are made up of eukaryotic cells

17. How do they compare?

18. Microscopes compound light microscope - uses 2 or more lenses to magnify objects can magnify up to 1500 x

19. Electron microscopes use a beam of electrons to magnify objects developed in 1930- 1940s magnifies 50 000x and more!

20. Scanning Electron Microscope 3-D picture is produced sweeps beams of e- over specimen magnifies up to 60 000x

21. Transmission Electron Microscope aims beams of e- through specimen can magnify up to 100 000x

22. Scanning Tunneling Microscope probe detects atoms at surface of specimen can magnify objects up to 100 000 000x!