1. Cells
Introduction

2. First – Review of Microscopes!
And a quiz right after!

3. Microscopes Simple light microscope One lens Living or dead specimen
From:

4. Microscopes Compound light microscope more than one lens
resolution is a problem
Must be transparent
(very thin)
Living or dead specimen
This is what we use

5. Microscopes Electron microscopes –
use a beam of electrons (on a dead specimen)
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6. Microscopes Electron microscopes types–
Transmission (TEM)- electrons pass through - very thin specimen
Scanning (SEM)- electrons bounce off and get an image from the outside
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7. Microscopes Other types– Scanning tunneling Uses a microprobe
Can be used on living or dead organisms
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8. Microscope Parts

9. Miscroscope Parts
Remember, the compound microscope has more than one system of lenses
The first lens system is the ocular or eyepiece located at the top of the microscope.

10. Miscroscope Parts Objectives
Depending on your microscope, the lowest (and shortest) lens is often called the scanning lens as it is used to “scan” the specimen to find your “target” for viewing. Usually these lenses magnify specimens 4x.

11. Miscroscope Parts Objectives
The next two lenses are considered “high” and “low” power objectives because of the power of magnification they have. These may vary from 10x-43x

12. Base-area on which the microscope rests and used to help carry the microscope
Arm-vertical piece that supports the body; also used to help carry the microscope
Body Tube-the portion of the microscope that contains the objective lenses
Revolving Nosepiece-the assembly that contains the objective lenses

13. Stage-the platform upon which objects to be examined are placed; Some can be moved up and down
Stage Clips-hold the object to be viewed in place
Condenser-lens that concentrates light on objects to be viewed

14. Diaphragm-series of holes that control the amount of light that reaches the object to be viewed. Sometimes aperture (opening) numbers are found on holes
Illuminator-light source; usually an electric light or a mirror

15. Course Adjustment Knob-used to bring the object into view
Course Adjustment Knob-used to bring the object into view. Always look to the side when using this and NEVER use it with the high power objective.
Fine Adjustment Knob-used to clear up the view of the object. Can be used with any objective lens.

16. Ocular lens (Eyepiece)
Body Tube
Nosepiece
Arm
Objectives
Scanning-shortest
Low-mid-size
High-longest
Stage
Stage Clips
Coarse Adjustment
Diaphragm
Fine Adjustment
Light
Base
Condenser

17. Microscope Parts Eyepiece (ocular lens) Tube (body)
From:
Eyepiece (ocular lens)
Tube (body)
Revolving Nosepiece
Objectives
Scanning
Low
High
Focus knobs
Coarse
fine
Base
Stage
clips
Diaphragm/iris/condenser
Light
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19. Characteristics of Microscopes
Magnification
Image appears larger than it is
Eyepiece 10x
Objectives 4x, 10x, 40x*
Resolution
Clarity of the image
Gets poorer with increased magnification
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20. Magnifications: Simple light: 5-25x Compound light: up to 2000x
Electron microscopes
SEM 200,000x
TEM 2,000,000x
Scanning tunneling: 1,000,000,000x
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21. Care and Use
1. Always carry the microscope with 2 hands by the arm and the base
2. Cleaning-be sure that all lenses are clean using lens paper provided by your teacher and wiping off lenses in circular motions. Plain water may leave images blurry.

22. Care and Use
3. Turn on the microscope and then rotate the nosepiece to click the scanning objective into place.
4. Place a slide on the stage and secure it using the stage clips.

23. 5. Focusing
a. While looking from the side, Turn the course adjustment know until the lens is as close to the specimen as possible without touching it. 
b. Look into the ocular and use the coarse adjustment knob (large knob) to bring the image into view. Look through the eyepiece lens and focus until the image is clear
**NEVER USE THIS KNOB ON HIGH POWER! It may crash into the slides which could break both the slides and the lenses!

24. Focusing
c. Use the fine adjustment knob* (small knob) to make is sharper or to finish the focus.
*This knob may be used freely with any power.

25. Once you have an image in view using the scanning objective, rotate the nosepiece to view it under different powers.
1. When you want to change the view of the object between low and high powers you will only need to use the fine adjustment knob.
2. Again, you should NOT focus with the course adjustment knob while using high power, as it leads to broken slides and damaged lenses!.

26. Adjustment of Light-
- The diaphram controls the quality of light that reaches the slide.
- To control the light adjust only the diaphragm. Be careful-too much light can wash an image out and make it harder to see!

27. ***Special Note: As we increase the power of the objectives we use, the smaller our field becomes and we often require less light. In other words-we see less of the object but sometimes better detail.

28. When you are done viewing objects, return your microscope to its storage place with the light source off and the scanning objective in place. Put away all your slides!

29. What's Your Power?
To calculate the power of magnification, multiply the power of the ocular lens by the power of the objective.
10 x 40= 400x

30. Which of these images are viewed at a higher power of magnification?
Comparing Powers of Magnification
We can see better details with higher the powers of magnification, but we cannot see as much of the image.
Which of these images are viewed at a higher power of magnification?

31. Microscope Images Mitochondrion Parasitic insect emerging from host
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32. Microscope Images
Mouse lung
DNA
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33. Examples from light microscopes
Pseudostratified ciliated columnar epithleium
Simple columnar epithelium
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34. Summarize your Notes Quiz time!
More on Cells to come!

35. The Scientists

36. Robert Hooke (English, 1665)
Looked at cork and named cells - after rooms in a monastery
thought only plants had cells
“...I could exceedingly plainly perceive it to be all perforated and porous, much like a Honeycomb...these pores or cells , were not very deep, but consisted of a great many little boxes...” --Hooke describing his observations on a thin slice of cork.
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37. 2/17/2019
From:

38. Anton van Leeuwenhoek (Dutch, 1674)
First to use microscope to observe living cells
Father of microbiology
looked at pond water - animacules (little animals)
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39. Cell Theory Matthias Schleiden (1838) All plants are made of cells
Theodore Schwann (1839)
All animals are made of cells
Rudolf Virchow (1858)
All cells come from preexisting cells
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40. Cell Theory All living things are composed of one or more cells.
Cells are the basic units of structure and function in living things.
All cells come from preexisting cells.
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41. Cells
Introduction

42. Cell Size and Function

43. Structure and Function
From:
Captions/Cellmethods/54.blood.Wright%27s3.html
From:

44. Structure and Function
From:
Structure and Function
Nerve tissue
From:
Examples of skin and nervous tissue
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45. Structure and Function
Skin Tissue
From:
Examples of skin and nervous tissue
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46. Structures and Functions
From:
Fat
Example of fat cells
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47. Cell Size
Most organisms have many small cells rather than fewer large ones
Why?
Surface area-to-volume ratio
6:1 good
3:1 very large for cells
Any lower than this is very dangerous

48. Cell Size
Most organisms have many small cells rather than fewer large ones
Why?
Allows transfer of materials in and out of cell easily
Cell size = small, Surface Area:Vol = high
Cell size = large, Surface Area:Vol = low

49. 2/17/2019

50. All cells have… Cell membrane – around outside
Cytoplasm – fluid of cell
Cytoskeleton – structure of cell
Ribosomes – make protein
DNA – used as instructions to make protein
Some lose these after time due to specialization
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51. Prokaryotes Bacteria Single celled organism
Lacks nucleus and membrane bound organelles*
DNA in a circular loop
Cell wall
*An organelle is a structure within a cell that performs a specific function
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52. Eukaryote
Organism that has cells with nuclei and internal compartments (membrane bound organelles)
ex. animals, fungi, plants, protists
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53. 2/17/2019 From: http://www.windows.ucar.edu/tour/l
ink=/earth/Life/cell_organelles.html&edu=elem
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54. 2/17/2019

55. Summarize your Notes Quiz next time!
More on Cells to come!