1. Microscopes and the Cell Theory
All About Cells
Microscopes and the Cell Theory

2. Microscopes of Today
At lot of times, when we think of a object, we think of it as it is today.
For example, a cell phone.

4. Cell Phones
So when we think of cell phones, we think of the ones we see today. The ones that we know and many of us use. But what about the original cell phones?

6. Microscopes
Just as there are difference between the cell phones we use now and the original cell phones, there are also differences in the microscopes we use today and what the original scientists who first looked at cells had available to them.

13. Historical microscope images, and more, can be found at: http://www
Historical microscope images, and more, can be found at: antiquecollection.html

14. The observations and conclusion of many scientists helped to develop the current understanding of the cell.
Robert Hooke
Anton van Leeuwenhoek
Matthias Schleiden
Theodor Schwann
Rudolph Virchow

15. The Discovery of the Cell
Early Scientists
Robert Hooke (1665)
Observed a cork slick and saw that it seemed to be made up of tiny, empty chambers.
Hooke called these chambers cells, because they resembled the tiny rooms of a monastery.

16. The Discovery of the Cell
Early Scientists
Anton van Leeuwenhoek (1674)
Used a single-lense microscope to observe pond water
Saw tiny living organisms, which he called “animalcules” and we know today as bacteria

17. Matthias Schleiden (1838) – concluded that all plants are made up of cells

18. Theodor Schwann (1839) – concluded that all animals are made up of cells

19. Rudolph Virchow (1855) – proposes that all cells come from preexisting cells, completing the cell theory

20. The Cell Theory Cells are the basic unit of life.
The cell theory states that:
All living things are composed of cells
Cells are basic units of structure and function in living things
New cells are produced from existing cells

21. The Cell Theory
Remember, before the Cell Theory, we had Spontaneous Generation – that life can arise from nonliving matter.
The scientists who worked to disprove this idea are:
Redi
Spallanzani
Pasteur

22. Redi’s Experiment

23. Spallanzani’s Experiment

24. Pasteur’s Experiment

25. Exploring the Cell Common Microscope Types:
Light microscope – living organisms, but low resolution
Electron microscopes - view details 1000 times smaller than visible in light microscopes. Non-living specimens. Requires vacuum.
Scanning Probe microscopes – Can operate in air, and can show DNA, protein molecules, and even single atoms.

26. Light Microscope

27. Electron Microscopes
Transmission Electron microscopes – requires thin specimens, can view cell structures and large protein molecules.
Organelles in a pollen grain of tobacco (Nicotiana tabacum; AF = Actin filaments; G = Golgi apparatus; Mi = Mitochondrion; Mt = Microtubule).

28. Electron microscopes
Scanning Electron microscopes – 3D

30. Scanning Probe Microscopes

31. PROKARYOTES
EUKARYOTES
DNA
Cells that have genetic material that is not contained in a nucleus; called a nucleoid region
Cells that contain a nucleus in which their genetic material is separated from the rest of the cell
Size
0.2-10μm
5-100μm
Organization
Usually single-celled; generally smaller than Eukaryotes
Can be single celled, but often multicellular
Examples
Bacteria
Plants, animals, protists, fungi

32. Prokaryote Cells

33. Eukaryotes Cells