Cell Lab
DO NOT WRITE ON
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Purpose: To make observations of plant and animal cells and learn some of the differences
and similarities that exist between them
Part A: Elodea Cells (plant)
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With forceps, remove a young leaf from near the tip
of an Elodea plant.
Place the leaf in a drop of water in the center of a
slide, cover with a cover slip, and observe under low
and high power.
Under high power magnification, as the slide begins
to warm up, you will see the chloroplasts and
cytoplasm begin to move or stream inside the cell.
This streaming process is known as cyclosis.
Answer questions 1-3 before going on.
Now add a 5% salt solution to your slide by placing a drop or two at the edge of the
cover slip. This will cause the cell to lose water (dehydrate) and the cell membrane
will shrink away from the cell wall. This shrinking of the cell within the cell wall is
knows as plasmolysis.
Answer question 4.
Part B: Onion Cells (plant)
1. With forceps, carefully remove a very thin layer of onion skin. (The inner side of
the skin may be readily peeled.)
2. Place onion skin in the middle of a slide and add 1 drop of water. (Make sure onion
skin does not fold over on itself.)
3. To see the nucleus of the cell, you will have to stain the onion skin with iodine. Add
one drop of iodine to the onion skin and cover with a cover slip.
4. Observe using both low and high power.
5. Answer questions 5-9.
Part C: Cheek Cells (animal)
1. Gently stroke the inside of your cheek with a toothpick and swirl it in a drop of
water on the center of a slide.
2. Add a small drop of methylene blue to stain the membrane and nucleus and cover
with a cover slip.
3. Answer questions 10-16.
Cell Lab Worksheet
Name
Period
Remember the four steps for making a proper field of view drawing!!! Make all drawings on
the back of this paper.
Questions
1. **Make a drawing of one Elodea cell as you observe it under high power. Label the
CELL WALL, GREEN CHLOROPLAST, and CYTOPLASM.
2. Write some general observations about the Elodea cell: shape, color, appearance,
etc.
3. Were you able to see the streaming movement of the cytoplasm? If so, which
direction did it flow (clockwise or counter clockwise)?
4. **Make another drawing of an Elodea cell after plasmolysis. Label the CELL
MEMBRANE, GREEN CHLOROPLAST, and CYTOPLASM.
5. **Draw one onion cell on high power. Label the CELL WALL and NUCLEUS.
6. Write some general observations about the appearance of the onion cell.
7. What structures usually found in plant cells are missing in the onion cell? Why?
8. Therefore, what process can’t the onion carry out?
9. What then is the function of an onion to the plant?
10. **Make a drawing of one of your cheek cells on high power. Label the NUCLEUS and
CELL MEMBRANE.
11. Write some general observations of this animal cell.
12. What structure previously seen in plant cells are absent from human cells?
13. In what ways is the onion skin cell, the Elodea leaf cell and the human cheek cell
alike and in what ways are they different?
14. Which kind of cells is more box-like and have more clearly defined boundaries?
Determining Cell Size
When looking through the microscope in low power the field of view has a diameter of
1350μm (1.35mm). The field of view in high power is 300μm (0.3mm).
Follow the directions to determine the size of the 3 cell types you observed in class.
1. Use your drawings of the Elodea, onion and cheek cells on high power for these
calculations.
2. Estimate the number of same-sized cells that could fit side by side (width) or end
to end (length) across the circle’s diameter.
3. To determine cell size in high power, divide 300μm by the total number of cells that
would fit across the circle’s diameter.
Fill in the following table (in μm):
ELODEA CELL
Length
Width
ONION CELL
CHEEK CELL