Examination of Prokaryotic and Eukaryotic Cell Biology
Structures Lab
Examination of Prokaryotic and Eukaryotic Cell Structures
Prokaryotic Cells:
Provided for you are two demonstration slides of bacterial cells. Make drawings of each of the two
specimens in the space provided. Notice that the magnification used is 1000x.
1. Escherichia coli
2. Staphylococcus epidermitis
Notice first that the cells are extremely small even at this high magnification. As you proceed through the
activity today make mental notes of the relative size of these cells to the other eukaryotic cells you will observe.
Eukaryotic Cells
As you look at the cells during this laboratory, think about what organelles may be present. Think
about the function of the cells and then about the organelles that you saw. Does what you found
make sense?
1. Onion Epidermis
The epidermis of an onion is merely the outer layer of cells that surrounds the onion. What
part of the onion is being examined?
Before you add stain:
A. Describe the appearance of the onion tissue before you put it under the microscope.
.
B. Do the cells have color?
Prepare a wet mount slide
C. Is there any movement? Are the
cells alive
D. Do you see anything? A nucleus?
Name________________________________________________1
Examination of Prokaryotic and Eukaryotic Cell Biology
Structures Lab
Add iodine as a stain
E. Make a drawing of a single cell at high dry magnification. Make the cell proportional to
the field of view represented by the circle above. Label the drawing, include the
magnification. Include the following structures: cell wall, cell membrane, cytoplasm,
nucleus, nuclear membrane, nucleolus
Allium cepa
2. Elodea Cells. You will examine the cells that are at the very edge of the leaf of this plant. At
the edge, the cells should be just one or two cells thick. No stain is required. Prepare a wet
mount slide and examine as above. Make a drawing in the space provided, label
appropriate structures and include the total magnifications.
Elodea canadensis
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Examination of Prokaryotic and Eukaryotic Cell Biology
Structures Lab
3. Human Cells: Cheek cells… (from your mouth)
A. Make a wet mount slide of your cheek cells.
i. Add a drop of methylene blue stain to a clean slide.
ii. Carefully scrape the inside of your mouth with a toothpick.
iii. Gently stir the scrapings into the stain.
iv. Dispose of the toothpick appropriately
v. Examine the slide under high dry magnification
B. sketch and label at least three cells with the appropriate cell structures.
What is the outermost organelle ?
How is the shape different from the
shape of the onion cell?
Are cheek cells alive?
What organelles can you see?
Which ones do you think should be present?
Why can’t you see them?
Overall, after looking at the prokaryotic specimens and eukaryotic specimans compare and contrast
what you saw.
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