1. How we discovered that all LIVING things were made of cells
Cell Theory
How we discovered that all LIVING things were made of cells

2. Robert Hooke – (1665)
Using a microscope he saw little boxes in cork he called cells

3. Cork looked like monastery cells

4. Leeuwenhoek – (1673)
Saw first living cells with microscope

5. How did he use such a microscope?
Place specimen in water drop here
Look through here
Adjust here

6. So stop complaining about your compound microscope

7. Schleiden (1838)
A Botanist
Concluded all plants are made of cells

8. Schwann (1839) An animal embryologist
Concluded all animals are made of cells

9. Schwann Sounds like swan (animal)

10. Virchow (1855)
All Cells can only arise from other pre-existing cells

11. Cell theory : All living things are composed of cells
Cells are alike in their basic structure and function in an organism
Cells need information to survive
Cells only come from reproduction of existing cells

12. Why are cells so small?
1) efficiency – if surface area to volume ratio too small, substances can not pass in and out quick enough
2) specialization – different cells have different functions

13. Types of cells
Prokaryotes
Eukaryotes

14. Prokaryotic cells Prokaryote= “before nucleus”
No Nucleus or other organelles with membranes
Mostly bacteria
All are unicellular

15. Key structures of prokaryotes
Nucleoid DNA (not enclosed)
Cell wall
Capsule surrounding cell
Plasma membrane
Cytoplasm
Ribosomes
Flagella (some)
pili

16. Eukaryotic cells Eukaryote = “true nucleus”
Have DNA contained in a nuclear membrane
Have a Plasma membrane surrounding
Have organelles surrounded by membranes (Golgi bodies, ER, mitochondria, lysosomes etc.)
Also have ribosomes
Unicellular
and multi cellular types

17. Eukaryotic cells = Animal and Plant
Most organelles are the same for plant and animal cells. Some differences are
Animal – centrioles
Plant –chloroplasts, central vacuole, cell wall

18. Observation of Cells with microscope

19. Basic Parts of cell
Plasma Membrane
Cytoplasm
Nucleus

20. Animal Cells Nucleus Cell membrane Cytoplasm Other organelles not
visible
400X

21. Plant cells also have chloroplasts and a cell wall
Nucleus
Cell wall
Cell
membrane
Chloroplasts
1000X

22. Drawing cells under microscope
Draw a neat diagram Not this
like this 2-3 cells
400X Nucleus
Remember: magnification and labels