Download Lab: Comparing Plant and Animal Cells

Lab: Comparing Plant and Animal Cells
Problem: What cell structures can be seen with a light microscope?
Materials:
Flat toothpick
Microscope
Slides
Cover slips
Medicine droppersElodea plant
Scalpel
Onion
Forceps
Methylene blue
stain
All of this must be copied
into your lab journal!
Procedures:
Human epithelial (cheek) cells
1. Using a medicine dropper place a drop of methylene blue on a slide. Gently
scrape the inside lining of your cheek with the flat edge of a toothpick. Mix the
material on the toothpick in the drop of stain. Immediately dispose of the
toothpick in the trash. CAUTION: Do not reuse toothpicks. Add a coverslip to
the slide.
2. View under low power, moving the slide to center a single cell in the field.
Change to high power and observe the cell carefully.
3. Record your observations in the data table. Sketch the cells and label the
structures inside.
Onion cells
4. Using a medicine dropper place a drop of methylene blue on a slide. Carefully
peel a very thin layer of onion skin from the onion and place a small piece of
the onion skin on the slide. Add a coverslip.
5. Focus on low power first and then on high power. Repeat step 3.
Data and Observations:
Cell Type Sketch and
Magnification
Name and
Number of
Structures
Other
Observations
Human
Cheek
Cells
Onion
Cells
Questions and Conclusions:
1. What structures did you observe in the onion but not in the human cells?
What are their functions?
2. Methylene blue is a common type of stain. What was the function of this
stain? Why are stains necessary in cell observation?
3. Compare the shape of the onion cells to the shape of the cheek cells. What
accounts for the difference?
4. What structures were visible in all the cell types?
5. What differences were seen between the plant and animal cells?