Exploring Eukaryotic Cells
Part A: Observing Animal Cells
Animal name: Homo sapiens (epithelial cells)
1. Epithelial cells line surfaces inside and outside our body. Gently, with the rounded end of a toothpick,
scrape the inside of your cheek to remove some of these cells.
2. Rub these cells on the surface of a slide; at this point many cells will be transferred. Immediately break
the toothpick and throw it away.
3. Add a drop of methylene blue and a cover slip. CAUTION: Stain can damage clothing.
4. View under low, medium and high power.
5. Draw 2-3 cells as they appear under high power. Label the cell membrane, cytoplasm, and
nucleus of one cell. Label your sketch with the animal name, magnification, and estimated size
(diameter) of one cell in micrometers (m).
Part B: Observing Plant Cells
Plant name: Elodea
1. Elodea is an aquatic plant with very thin leaves. It is possible to mount a whole leaf and examine living
cells.
2. Pull the leaf from the tip of the Elodea sprig and mount it with a drop of water and a cover slip.
3. Examine it under low, medium and high power.
4. Draw 2-3 cells as they appear under high power. Label the cell membrane, cell wall, cytoplasm
and chloroplasts of one cell. Label your sketch with the plant name, magnification, and
estimated size of one cell in micrometers (m).
Plant name: Allium (onion)
1. Separate a piece of onion from the bulb. Hold it in your fingers and snap it in half. Peel away a piece
of the thin transparent covering from the inside of the curved section.
2. Mount this thin layer of tissue on a slide being careful to keep it just one layer on the slide (don’t let it
fold), add a drop or two of iodine and a cover slip. CAUTION: Stain can damage clothing.
3. Examine it under low power first and then move to medium and high power.
4. Draw 2-3 cells as they appear under high power. Label the cell membrane, cell wall, cytoplasm
and nucleus in one cell. Label your sketch with the plant name, magnification, and estimated
size of one cell in micrometers (m).
Analysis:
1. What evidence do you have that each of these organisms is eukaryotic?
2. What evidence do you have that Elodea is autotrophic? What evidence do you have that humans are
heterotrophic?
3. Compare the shape of the plant cell with the shape of the animal cell. What accounts for the difference
in shape?