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COMPARING PLANT AND ANIMAL CELLS
Background Information
All living things are made of cells. Cells are the basic units of structure and function of living
things. There are many types of cells. Whether they are plant or animal cells, most cells share
certain characteristics.
In this investigation you will compare the structures of a typical plant cell (Elodea) and a typical
animal cell (human cheek cell).
Problem
How are plant and animal cells alike? How are they different?
Materials (per group)
Forceps
Medicine dropper
Elodea leaf
Microscope
2 microscope slides
2 coverslips
1 toothpick
Methylene blue stain
Paper towel
Procedure
Part A: Examining Animal Cells
1. Place a small drop of methylene blue onto a slide.
2. Using the flat end of a toothpick, gently scrape the inside of your cheek.
CAUTION: Do not use force when scraping the inside of your cheek. You will
not be able to see anything on the toothpick when you remove it from your
mouth.
3. Dip the toothpick into the stain on the slide and mix. Add a coverslip.
4. Place the slide on the stage of the microscope with the center of the
coverslip directly over the opening in the stage.
5. Using the low-power (10X) objective lens, locate a few cheek cells under
the microscope. Locate and examine cells that are separated from one
another rather than those that are in clumps.
6. Switch to the high-power (40X) objective lens.
7. Observe some cheek cells. The outer covering of the cheek cell is the cell
membrane. All cells have a cell membrane surrounding the contents of the
cell. All of the fluid contained inside of the cell makes up the cytoplasm.
8. Notice the dark circular structure in the center of the cell. This is the nucleus,
or the “brain” of the cell. All eukaryotic cells (both plant and animal) contain a
nucleus. The nucleus is visible because it is stained by the methylene blue.
9. Draw 1 cell and label the cytoplasm, nucleus, and cell membrane.
Cheek cell (40X)
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Part B: Examining Plant Cells
1. Put a drop of water in the center of a clean slide.
2. With the forceps, remove a small piece of leaf from the Elodea plant and
place it on the slide. Make sure that the leaf is flat. If it is folded, straighten
it with the forceps.
3. Carefully place a coverslip over the drop of water and Elodea leaf.
4. Place the slide on the stage of the microscope with the leaf directly over the
opening in the stage.
5. Using the low-power (10X) objective lens, locate the leaf under the
microscope. Turn the coarse adjustment knob until the leaf comes into
focus. When you have focused the leaf, have your teacher check to see if
it is focused correctly.
6. Switch to the high-power objective lens.
7. Observe the cells of the Elodea leaf. Each cell should look like a brick that is
part of a large brick wall. Each individual “brick” is one cell. The outer
covering of the plant cell is the cell wall. The cell wall surrounds the cell
membrane in a plant cell. It is stiff and rigid and provides support to the cell.
8. Note the small green organelles inside each cell. These are chloroplasts.
Movement of the chloroplasts within the cell often can be observed. Attempt
to locate moving chloroplasts. It is the cytoplasm that moves the
chloroplasts along. (If the cytoplasm is not moving you may have to wait 5 to
10 minutes for the specimen to become adjusted to the slide and mount.)
9. Although all plant cells have a nucleus, this organelle will most likely not be
visible under your microscope.
10. Draw 1 Elodea Cell and label the cell wall, cytoplasm, and chloroplasts
as you see them under the microscope. Use high power (40X).
Elodea cells (40X)
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Analysis and Conclusion
1. Describe the shape of the Elodea cells.
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2. Describe the shape of the cheek cells.
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3. Complete this chart. Indicate by using check marks each structure contained
in a plant or animal cell. (Even if these structures were not visible in the lab)
NUCLEUS
CELL
WALL
CYTOPLASM
CHLOROPLASTS
CELL
MEMBRANE
ANIMAL
CELL
PLANT
CELL
4. Which 2 parts that you observed in the lab are only found in a plant cell?
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5. What 3 parts of the cheek cells did you observe?
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6. What movement did you observe in the Elodea cells?
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Critical Thinking and Application
1. Explain why methylene blue was used to observe the cheek cells, while
only water was used to observe the plant cells.
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2. Explain how the function of the cell wall is different from the cell
membrane?
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3. If you were given a slide containing living cells, how would you identify
the cells as either plant or animal? Give at least 2 examples.
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