Download Name

Cytologist________________________
Date__________
Are All Cells Alike?
Key Question: Are the structures and functions of cheek cells (animal cells) the
same or different from those of onion cells (plant cells)?
Today you will work in pairs as cytologists to answer this question. You will be
preparing wet mounts of both an onion cell and a cheek cell, observing your
slides under the microscope and comparing and contrasting your observations.
You will be recording your observations by making accurate sketches and will
have to carefully label the parts of the cell that you can identify.
Assessment: The skills listed in this table are worth 10 points each. Following
the completion of the lab list next to each criterion how many points you think
that you earned. Your answers to the discussion questions at the end of the lab
will also be part of your assessment. Each question at the end of the lab is
worth 4 points.
What I think I earned
What I earned
Skill
Recorded accurate,
complete neat notes
about structure and
function of plant and
animal cells
Followed lab safety rules.
Properly handled
microscope
Worked cooperatively
with my partner
Correctly followed
procedure for preparing
wet mount slides of a
check and onion cell
Carefully drew what I
observed
Completely answered
questions so that I
communicated that I
understood important
ideas
Procedure: Onion Cell
1. Place a thin onion skin piece onto the center of a slide. Add a drop of water and then a cover slip.
2. Carefully observe under low power. Record the power of magnification. Draw what you see in
Figure 1.
4. Now remove the cover slip and add one or two drops of methylene blue. Add the cover slip.
Switch to higher power. Record the power of magnification.
Draw what you see in Figure 2.
Label the following organelles: cell wall, cell membrane, nucleus, and cytoplasm.
Figure 1: My Drawing of an Onion Skin Cell
Power of magnification
Low Power =______
Figure 2: My Drawing of a Stained Onion Skin Cell
Power of magnification
High Power = ______
5. Is an onion cell a plant or animal cell? ____________________________________
6. What is the shape of the onion
cell?_____________________________________________________________________________
________________________________________________________________________________
7. Does the outer boundary of the cell appear as a double or single line?
________________________________________________________________________________
________________________________________________________________________________
8. Name one part the plant cell has that the animal cell does not. Why does it have this part? What
does it do?
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
Procedure: Cheek Cell
1. Place a small drop of methylene blue dye onto a clean slide.
2. Using a flat toothpick, gently and carefully scrape the inside of you cheek.
3. Place the toothpick tip into the dye and mix. The dye stains the cells so you
can see them. Immediately throw your toothpick away.
4. Place the slide under low power. Record the power of magnification. Carefully draw what you see
in Figure 3.
5. Switch to high power. Record the power of magnification. Carefully draw what you see in Figure 4.
Label the nucleus, cell membrane, and cytoplasm. Draw a straight line from the cell part to its label.
Figure 3: My Drawing of a Cheek Cell
Under Low Power of Magnification _________
Figure 4: My Drawing of a Cheek Cell
Under High Power of Magnification _________
Analysis:
1. What is the shape of the cheek cells?
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
2. Why did we add dye to our cheek cells?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
3 . What is the dark round shape inside each cell?
________________________________________________________________________________
________________________________________________________________________________
4. Describe the way the cytoplasm looks.
________________________________________________________________________________
________________________________________________________________________________
5. Looking at the dark outline around the cheek cell, does this boundary appear as a single or double
line?
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
6. What is the outer boundary around the cheek cell called? What is its
function?_________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
7. Is your cheek cell an animal cell or plant cell?
________________________________________________________________________________
________________________________________________________________________________
8.
As you adjusted the microscope to higher magnification, what happened to the number of cells that
you could see in your field of view?
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
9. As you adjusted your microscope to higher magnification, what happened to the detail that you
could see?
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
10. Count the number of cells that are seen in the field of view under low magnification and also
under high magnification. Using a ratio, (L;H) compare the number of cells observed in each field of
view.____________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
Conclusion: (After completing this investigation, I learned…
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________