Warm Up
Create a word web with words you think of when you hear
"Biology"
Biology
Unit 2 - Reproduction
-Cell Growth and Reproduction
-Cell Division
-Sexual and Aesexual Reproduction
Zygotes and Development
During the 1800s scientists constructed what has come to be known as cell theory.
This is where we will begin.
The theory is based on 3 important principles:
1) All living things are composed of one or more cells.
2) The cell is the functional unit of life.
3) All cells come from pre-existing cells.
Scientific discovery oftens depends on technology available. Cell theory used technological
advances in Microscopy to advance (aka THE MICROSCOPE)
Microscopes provided scientists with a new view of cells.
Greater magnification allowed them to discover smaller cells AND to gain a better
understanding of how cells worked!
Magnification
Magnification needed
to create a 1-mm image
Object
Magnification
Fish Egg
none
Human Egg
10x
Plant Cell
20x
Animal Cell
50x
Bacterium
1000x
Large Virus
10 000x
Ribosome
40 000x
Cell Membrane
100 000x
Hydrogen Atom
10 000 000x
What’s my power?
To calculate the power of magnification, multiply the power of the ocular lens by the power of the
objective.
What are the powers of magnification for each
of
the objectives we have on our microscopes?
Fill in the table on
your worksheet.
Parts of a Microscope
Ocular lens
(Eyepiece)
Body Tube
Nosepiece
Arm
Objectives
Stage
Stage Clips
Coarse Adjustment
Diaphragm
Light
Fine Adjustment
Base
Always carry a microscope with one hand holding the arm and one hand under the
base.
aperture
TOUCH THE SHAPE TO SEE IF YOU CAN NAME EACH PART
CORRECTLY!
DIAPHRAGM
1. ____________________ This disk under the stage controls the amount of light that
passes through the
aperture.
2. ____________________ The mirror or lamp is located between these two things.
LEGS
3. ____________________
The flat place under the objective lenses where you place th
slide for viewing.
4. ____________________ This is the support for the entire microscope.
STAGE
5. ____________________
This part supports the entire upper portion of the microscope
BASE
ARM
LAMP OR MIRROR
6. ____________________ This provides light so that so
that it is easier to see the object you are viewing.
7. ____________________ There may be 2 or 3 of these mounted to the nosepiece that
magnify
at different
powers.
OBJECTIVE
LENSES
8. ____________________ Light passes from the objective lens to the eyepiece through
part of the microscope.
9. ____________________
These keep the slide from
BODY TUBE
moving around the stage.
10. ___________________ Where you look into the microscope. It also provides
magnification.
STAGE CLIPS
EYEPIECE
11. ___________________ Once the object that you would like to view comes into focus
FINE ADJUSTMENT KNOB
you use this to fine-tune the image.
12. ___________________ This is the thin piece of glass where you place your specime
SLIDE
13. ___________________
You begin your focusing with
this part of the microscope.
14. ___________________ The opening in the stage that allows light through.
15. ___________________ The objective lenses are
mounted to this part of the microscope.
COURSE ADJUSTMENT KNOB
APERTURE
NOSEPIECE
Using a Microscope
How to make a wet-mount slide …
1 – Get a clean slide and coverslip from your teacher.
2 – Place ONE drop of water in the middle of the slide. Don’t use too much or the water will run off the
edge and make a mess!
3 – Place the edge of the cover slip on one side of the water drop.
5 – Place the slide on the stage and view it first with the red-banded objective. Once you see the image, you
can rotate the nosepiece to view the slide with the different objectives.
You do not need to use the stage clips when viewing wet-mount
slides!
Let’s give it a try ...
1 – Turn on the microscope and then rotate the nosepiece to click the red-banded objective into place.
2 – Place a slide on the stage and secure it using the stage clips. Use the coarse adjustment knob
(large knob) to get it the image into view and then use the fine adjustment knob (small knob) to make it
clearer.
3 – Once you have the image in view, rotate the nosepiece to view it under different powers. Draw what
you see on your worksheet!
Be careful with the largest objective! Sometimes there is not enough room and
you will not be able to use it!
4 – When you are done, turn off the microscope and pick up the slides you used.