1. Unit C - Biology
Study of Life

2. A little history on the microscope
Hans and Zacharias Janssen
Invented the microscope in 1595
2 lens system (ocular lens & objective lens)
Magnifying power of 20x
Robert Hooke
Using hand made microscope in 1665
3 lens system (beam of light through a water filled flask)
Gained information on the structure of the cork – and named the holes – CELLS (latin for: small compartment)

3. A little more history Antoni Van Leeuwenhoek
Single lens microscope (ie magnifying glass)
1st to see movement in various types of single celled organisms (such as bacteria, sperm, unicellular protozoa etc)
250x magnification

4. Labeling the Microscope
Eyepiece
Body tube
Coarse adjustment knob
Fine adjustment knob
Revolving Nosepiece
Arm
Objective lenses
Stage
Stage clips
Base
Diaphragm
Light Source

5. Use your textbook to define the function of the microscope parts
Eyepiece or Ocular
Coarse adjustment knob
Fine adjustment knob
Revolving nosepiece
Objective lenses
Stage
Stage clips
Diaphragm
Lamp or Mirror
Arm
Base

6. How to focus a microscope
Ensure that the low power lens is in position
Watch from the side as you use the coarse adjustment knob to lower the lens until it is as close as possible to the stage.
Look through the eyepiece while using the coarse adjustment knob to move the lens upward
Once the image appears almost sharp, use the fine adjustment knob to finish focusing

7. High Power focusing
Move the objective upward with the coarse adjustment knob enough to revolve the high power objective lens into position.
Watch from the side as you lower it close to the slide
Use only the fine adjustment knob to fine tune the focusing

8. What you see through your microscope is called the ‘Field of View’
** What you see through your microscope is called the ‘Field of View’. In order to determine the actual size of the specimen, you must measure it on high and low power – and then convert it into micrometers.

9. Distance Units x1012 x109 x106 x103 x102 x101 pm nm µm mm cm dm m
centi
meter
nano
milli
micro
pico
deci
x1012
x109
x106
x103
x102
x101
x100 pm nm µm mm cm dm m

10. Assignment – take home Do the attached worksheet
Complete the check and reflect for section 1.1 #1-8

11. 1.2 – Cell Theory
Aristotle came up with a theory that life came from non- living matter.
Evidence
Mice come from sweaty socks and wheat husks
Maggots come from raw meat (this was challenged by Francis Redi)

12. Francis Redi’s Experiment
Control – same piece of meat
Manipulated variable – covering of container
Responding variable – flies/ no flies

13. John Needham’s Experiment
Boiled chicken broth then sealed jars and microbes still appeared. Boiling should have killed the microbes.
Someone else removes the air = no microbes
Argument – microbes need air

14. Louis Pasteur
Uses swan necked flask to prove microbes come from other microbes
Flasks allowed air to be present but the bacteria would settle
Control – broth, flask, light
Manipulated – access to the flask
Responding – ability to grow microbes

15. Summary of Cell Theory:
Hooke names them cells (from holes in cork)
Schwann & Scheilden- say all living things are made up of them.
Main points
All living things are made up of one or more cells
All life functions take place in the cell
All cells come from preexisting cells

16. Assignment
Check and Reflect 1.2 #1-5

17. Development in Imaging Technology & Staining
1.3 – 1.4

18. Seeing Small Objects
Magnification – how many times bigger something appears (ex 1mm will appear the size of a meter under 1000x magnification –our microscopes on high)

19. This has been magnified 3. 3x
This has been magnified 3.3x. Notice how the picture quality did not get better, it just got bigger.
Notice how it is hard to distinguish between where the knob ends and there is empty space. This has poor resolution.

20. Resolution – the ability to distinguish between 2 objects that are close together.
Contrast – is the ability to distinguish between 2 objects due to their ability to absorb light. Staining is the most common way to increase contrast – problem: It normally kills the organism. Stains bind to specific substances.

21. Other Contrast Enhancing Techniques
Fluorescence- attach fluorescent substance with an antigen and allow the antigen to bind with cell. Now the cell glows.

22. Confocal Microscope – takes pictures of cell at different levels
Confocal Microscope – takes pictures of cell at different levels. Computer reconstructs the pictures into a 3-d image.

23. Electron Microscope
Not dependent on the wavelength of light (allows you to see smaller objects)
Canadian invention
Uses a beam of electrons
TEM –Transmission Electron Microscope: Electrons are shot through thin slices of the specimen. Magnification ( x and a resolution 2.5nm vs 0.2micrometers for light. (100x improvement)

24. Plant Cell - 22,500X
C = Chloroplast ER = Endoplasmic Reticulum G = Granum M = Mitochondrion S = Starch Grain T = Thylakoids V = Vacuole W = Wall

25. SEM – Scanning Electron Microscope: Electrons are reflected off the surface of the specimen to get a 3-d picture of the outside of the critter. (Mag x, Resolution 20nm) Slightly less than EM
Tobacco seed

26. Some pics taken by LSL students in 2010/2011 on a portable SEM… Can you guess what they are?

27. Eye of a Fruit Fly

28. Fruit Fly eye
Notice the hairs…because they don’t have eye lids.

29. Pollen

30. Sugar

31. Hairs of a fruit fly

32. Salt

33. Stoma of a plant leaf
Opens and closes to allow for gas exchange and water release.

34. Many Stoma on bottom of Leaf

35. Wing of a Fruit Fly

36. Whole Fly
A Fly!

37. Fly Leg

38. Viewing @ the Molecular level
Scanning tunneling microscope and AFM (Atomic Force Microscope) – can view pictures of molecules.
X-ray crystallography helped construct DNA’s double helix