1. Cells
Organelles

2. CELL
The basic unit of structure & function in living organisms

3. Anton Van Leeuwenhoek 1632-1723
Was a merchant that ground up glass to make lenses
Invented microscope
Made over 500 in his lifetime
1st person to examine bacteria

4. Van Leeuwenhoek’s sketches of a nerve

5. Robert Hooke 1635-1702 Used Van Leeuwenhoek’s microscopes
Named cells after looking at cork

6. Robert Hooke’s Cork

7. Robert Brown
Discovered the nucleus in plant cells (1833)

8. Matthias Schleiden
Discovered all plants are made up of cells
(1838)

9. Theodor Schwann
Discovered that all animals are made up of cells (1839)

10. Rudolph Virchow
Proposed that all cells come from pre-existing cells (1855)

11. The Cell Theory The cell theory states:
All living things are composed of cells
B. Cells are the basic units of structure & function in living things
C. All cells come from preexisting cells

12. Janet Plowe
Demonstrated that the cell membrane is a physical structure (1931)

13. Lynn Margoulis
Proposed that certain organelles were once free-living organisms themselves (1970)

14. Parts of Microscope Nosepiece Ocular High Power Objective Arm
Low Power Objective
Scanning Power Objective
Stage
Stage Clips
Course Focus
Fine Focus
Diaphragm
Base
Light (illumination)

17. Compound light Microscope Parts & Fxn’s
Occular – viewing eyepiece
Coarse adjustment – Rough focus
Fine adjustment – Fine focus
High power objective (400X)
Low objective (100X)
Scanning objective (40X)

18. Compound Light Microscope Parts & Fxn’s
Stage – holds slide up against stage clips
Stage clips – holds slide down on stage
Diaphragm – controls amount of light entering slide
Lamp – light source
This is an air bubble
under the microscope!!!

19. Power of magnification
The relative enlargement of the specimen when seen through the microscope.
The power of magnification can be calculated by multiplying the power of the eye piece lens by the power of the objective lens.

20. Inversion The reversal of the specimen image by the microscope lenses.
A specimen that appears upside down when being viewed is actually right-side up on the slide.
Moving the specimen to the right causes its image to move to the left likewise, moving it down causes it to move upward.

21. Working distance
The distance between the front of the objective and the top of the cover glass on the slide.
The higher the magnification the smaller the working distance.
DO NOT USE THE COARSE ADJUSTMENT UNDER HIGH POWER!!!

22. Resolution (Resolving Power)
The shortest distance between two points or lines at which they are seen as two, rather than a single blur.
                               

23. Depth of focus
The thickness of a specimen which may be seen in focus at one time.

24. Objectives
Our microscopes have three objectives mounted on a revolving device known as a nosepiece.
Engraved on the objective is its power of magnification.
The longer the objective the more power of magnification.

25. Diaphragm
A device under the stage of a microscope that can regulate the amount of light reaching a specimen.

26. Power of Magnification
Definition - The relative enlargement of the specimen when seen through the microscope.
Power of magnification = (Power of the eyepiece lens) X (Power of the objective lens)

27. Rules for Handling the Microscope
Always carry the microscope with one hand under the base and the other grasping the arm.
Keep both eyes open when looking through the eyepiece.
Keep the stage clean and dry.
Do not remove parts of the microscope.
Use only lens paper when cleaning lenses.

28. Rules for Handling the Microscope
Always begin focusing with the lowest power objective.
Always look from the side when changes lenses
After completing your work, place the microscope on the lowest power objective.
Always return the microscope where you found it & as you found it

29. Modern Microscopes
Electron microscopes – capable of revealing details as much as 1000 times smaller than those visible in light microscopes. (Two types -TEM & SEM)
TEM – can explore cell structure and large protein molecules.
Downside – the specimens have to be sliced thinly

30. T.E.M.

31. Transmission Electron Microscopy T.E.M.

32. Modern Microscopes S.E.M. – Scanning electron microscopes –
specimens do not have to be cut thinly – a beam of electrons scans over the specimen.

33. S.E.M.

34. S.E.M. Magnification

35. Prokaryotic & Eukaryotic Cells