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Name: _________________
Block: __________
Date: __________
Animal and Plant Cells
Objective:
To observe, identify and compare the organelles of plant and animal cells.
Procedure:
1. Obtain a 1cm2 thin piece of onion skin.
2. Place in the center of a slide and prepare a “wet-mount” by adding two drops of water.
Cover this with a cover slip.
3. Begin observing at low-power (40x total). Make sure the onion skin is centered. Use the
coarse adjustment knob to focus the cells. Ask for help if you have difficulty.
4. Observe at medium and high power. Use only the fine adjustment knob. Using the
diaphragm, adjust the intensity of the light.
a. Which intensity of light (brightness) allows the better view of the onion cells?
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b. Complete a scientific drawing of a few onion cells at medium-power. Remember all
of the proper procedures for completing a drawing! Label any organelles that are
visible (cell wall, nucleus, cytoplasm, etc.). For organelles that can be seen but
are too small to be identified, label them as “unknown organelles”.
5. Add a drop of iodine solution to one side of the cover slip. Using a piece of tissue on the
opposite side, draw the solution across the slide.
6. Observe on low-power, medium-power and then high-power.
c. Complete a scientific drawing of a few onion cells at high-power. Identify any
organelles that are visible (cell wall, nucleus, cytoplasm, Golgi apparatus,
etc.). For organelles that can be seen but are too small to be identified, label
them as “unknown organelles”.
d. How did the iodine solution change what you viewed?
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e. Why do the onion cells, which are from a plant, appear not to have chloroplasts?
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7. Obtain a prepared slide Amphiuma liver, which is a relative of the salamander.
8. Observe on low-power, medium-power and then high-power. NOTE: I am unsure what
the brown spots are or why they exist.
f. Complete a scientific drawing of a few liver cells at high-power.
Identify any
organelles that are visible (cell membrane, nucleus, cytoplasm, etc.).
g. Choose one liver cell that you have drawn. Calculate its estimated size at 400x.
h. Calculate the diagram magnification of the scientific drawing of the same liver cell.
Overview Question:
Contrast the organelles that exist in plant and animal cells.
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