1. Unit One: Matter and Energy Flow in Cells
Biology 20
Unit One: Matter and Energy Flow in Cells
Topic Two:
The Microscope

2. Objects that can be observed by the unaided eye

3. Objects that can ONLY be viewed using a microscope

4. Introduction
The cell is the unit of structure of all living things. Living organisms include:
Plants
Animals
Bacteria
Protists
Fungi
All living things are made of at least ONE cell
Hundreds of years ago, no one knew this because cells were too small to be seen with the unaided eye
The creation of the MICROSCOPE proved the existence of cells!!!

5. Microscopes 1.Why do we use microscopes?
microscopes magnify objects and make small things appear larger
2.What is the main benefit of using microscopes?
- resolution or the ability to see detail
3 main types of microscopes:
Light/compound microscope
Transmission Electron Microscope (TEM)
Scanning Electron Microscope (SEM)

6. 3. How do we calculate the total magnification of an object using a light microscope?
Total magnification = magnification of ocular lens x magnification of the objective lens
Ocular Lens
10X
Total mag. = 10 x 40 = 400 times
Objective Lens
40X

7. 1. Light Transmission Microscope
Total Magnification:
1000X
The image is produced by
light passing through the specimen
The qualities of the image produced are:
color and 2-D

8. Light Transmission Microscope
Advantages of the light microscope include:
color image
living material may be used
Disadvantages include:
low magnification
poor resolution at higher magnifications as the light rays are bent (large images but little detail)
Amoeba moving video

9. Scanning Electron Microscope

10. Scanning Electron Microscope
TotalMagnification:
500,000X
Scans the surface of the specimen
The image is produced by
Electrons reflected off the surface
Often coat specimen with gold for a sharper image

11. Scanning Electron Microscope
The qualities of the image are:
3D, black and white picture of the surface of the specimen.
Advantages:
high magnification
3D image that can be easily understood
Disadvantages: specimen must be dead

12. Transmission Electron Microscope
Phillips CM 10 TEM
Mitochondrion
image taken by a TEM

13. Transmission Electron Microscope
Total Magnification:
1,000,000X
The image is produced by
electrons passing through the specimen
shorter wavelength than visible light
less scatter - sharper image
Qualities of the image are:
2D, high resolution, black and white

14. Transmission Electron Microscope
Advantages:
Highest magnification and high resolution
the internal detail of cell can be seen
Disadvantages:
2-D image
black and white image
the specimen must be dead; uses very thin slice of the specimen
image is difficult to understand

15. Transmission Electron Microscope
Scanning Electron Microscope
Light Microscope
Transmission Electron Microscope
TEM Microscope

16. SEM Images
Bed Bug

17. SEM Images
House Fly

18. More SEM images
Various blood cells
Image of a spider’s leg

19. More SEM images
Moth

20. 6. Objective lenses magnify 4x, 10x and 40x
Ocular lens
magnifies 10X
2. Body tube
4. Revolving nose piece
3. Arm
6. Objective lenses magnify 4x, 10x and 40x
5. Stage clip
7. Adjustment knob
8. Slide
9. Stage
10. Coarse adjustment knob (low power)
11. Iris Diaphragm
12. Light
13. Fine adjustment knob
15. Base
14. Power switch

21. Microscope parts and functions
Part Name
Purpose of Part 1
Look through this to see an object under the microscope. Usually 10X magnification. 2
Connects the ocular to the microscope. 3
Connects the base and the barrel. 4
Turns to change the objective lenses to use. 5
Holds the slide in place 6
Used to view objects at three different magnifications 7
Moves the stage side-to-side, or forward and back to get the object into the field of view
Ocular
lens
Body
Tube
Arm
Nose
piece
Stage Clip
Objective
lens
Stage
adjustment
knob

22. Microscope parts and functions
Part Name
Purpose of Part 8
Piece of glass onto which the object to be viewed is placed 9
Holds the slide for viewing 10
Raises and lowers the stage for focusing under low power 11
Adjusts the amount of light entering the field of view 12
Source of light 13
Slightly moves the stage to sharpen the image 14
Turns the illumination on or off 15
Supports the microscope
Slide
Stage
Coarse
focus
Iris
diaphragm
Lamp
Fine
Focus
Power
Switch
Base

23. How To Use a Microscope
Make sure the objective lens with the lowest power is in place.
Place the slide on the stage and secure the slide using the stage clip.
Use the coarse focus knob to bring the objective lens close to the slide. Use the fine focus knob to focus.
To move to high power, rotate the nosepiece to the high power objective lens. Use the fine adjustment knob to bring the image into focus.