Activity: Observing Animal Cells
Goals:
1. To use a microscope to observe animal cells.
2. To observe three major structures found in human
epithelial cells.
Background Information: The most obvious structures of an animal cell are the cell
membrane, cytoplasm, and the nucleus. These structures are easy to see under a
school microscope. Students can collect epithelial cells from their mouths by gently
scraping their inner cheeks. Epithelial cells are used for protection and forming the lining
of many body surfaces. They can be removed easily and are replaced quickly.
Materials: A blank slide, flat-edged tooth pick, cover slip, iodine solution or methylene
blue stain
Note: Please advise your teacher if you are allergic to iodine and/or shellfish!!!
Procedure:
1. What I Know: Write a sentence or two explaining what you already know about
animal cells.
2. Draw two circles on your lab sheet to represent fields of view for 40X and 100X.
3. Add a drop of iodine or methylene blue to a clean, blank slide. The purpose of
the iodine is to stain the cells so that there is contrast among the different cell
parts. For example, the nucleus will absorb more of the iodine and appear a
brownish color in contrast to the cytoplasm of the cell.
4. Gently scrape the inside of you cheek two or three times with the broad end of a
flat-edged toothpick.
5. Spread the wet material that you scraped from your cheek across the blank slide.
Do not apply too much pressure to the toothpick or slide. (Since these cells are
being removed from their natural position in your mouth, their shape may
become distorted if you push them around too much.)
6. What I Did: Write a summary of the procedure you used for this lab.
7. Beginning with 40X, observe the cheek cells and draw what you see.
8. What I Observed: Draw your observations only at 40X and 100X. Label the cell
membrane, cytoplasm, and nucleus of one cheek cell in one of your drawings.
Write a caption describing your drawings.
______ X
Cheek Cells
______ X
Cheek Cells
Caption:
9. What I Learned: Explain what you learned from this activity.
10. What I Wonder: Pose at least one question that arises from this activity or topic.
11. Questions: Answer the following in complete sentences.
a. Describe the shape of the cells you observed. (Example: The shape of the cells I
observed are ______________.)
b. Describe the function of each of the cell parts you observed.
c. Describe something that surprised you about your observations of the animal
cells.
d. Why is the methylene blue necessary?
Name: ____________________________________
Date ____________
Title of Activity: _______________________________________________________
1. What I Know:
2. What I Did:
3. What I Observed:
______ X
Cheek Cells
Caption:
4. What I Learned:
5. What I Wonder:
6. Questions:
______ X
Cheek Cells