Download Comparing Plant and Animal Cells

Name ___________________________________________________________________
Comparing Plant & Animal Cells
Pre-Lab Questions
Read the entire lab and answer the questions below. These questions must be answered BEFORE
you are allowed to do the lab.
1. What two types of plant cells are you observing? ________________________________
2. What precautions do you need to take when using the methylene blue stain? ____________
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3. Why should you use forceps when obtaining the plant cells? ________________________
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4. What is the purpose of the methylene blue stain in Part B of the lab? _________________
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5. How do you remove the stain from underneath the coverslip (include the part and step where
you find it in the procedures)? ________________________________________________
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6. Explain what you do with your slide when you are finished. __________________________
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7. What magnification are you to use when you draw your observation of the cells? _________
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8. Is the methylene blue stain corrosive, alkaline, or neutral? _________________________
9. What are the three steps to leave the microscope when you are finished with the lab?
a.
b.
c.
Comparing Plant and Animal Cells
In this investigation, you will compare the structures of a typical plant cell and a typical animal cell.
This lab consists of two parts. In Part A, you will observe three (3) different types of plant cells.
In Part B, you will observe human check cells.
You need to take care when gathering live cell samples. Scientists use tools such as forceps and
slides to “touch” the specimens. This prevents contamination and also ensures that the delicate
cells are not ruptured or damaged.
Problem – How are plant and animal cells alike? How are they different?
Materials
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Forceps
Pipette
Glass slides
Coverslip
Paper towel
Tomato
Onion
Plant leaf
Distilled water
Cotton swab
Methylene Blue stain
Iodine stain
Safety Concerns: Methylene blue/Iodine. This is a corrosive and will
burn. Do not get it on your skin. Wash any area immediately with
water. Inform Mr. Hill immediately. All students will wear gloves and
goggles while preparing slides.
Procedure
Part A – Examining Plant Cells
1. Get your container of distilled water, slide, and coverslip.
2. With forceps, remove a leaf from the Elodea plant and place it on a drop of water on the slide.
Make sure the leaf is lying flat.
3. Carefully place a coverslip over the Elodea leaf and place the slide on a microscope. Place the
coverslip at a 45o angle (approximately), with one edge touching the water drop, and let go.
4. Observe the leaf on low power. Switch to medium power and label what you see.
5. Carefully clean and dry your slide for reuse. Throw away your coverslip.
6. Get a thin slice of both tomato and onion skin. Repeat steps 3 through 5 for each sample.
(Note: if you cannot see anything, you may want to try to stain it with meth blue or iodine. See
below for staining instructions.)
Part B – Examining Animal Cells
1. Place a drop of water in the center of a clean glass slide.
2. Using the cotton swab, gently swab the inside of your cheek.
3. Swab the glass slide with your cotton swab. Throw away the cotton swab.
4. Put one drop of methylene blue stain on top of the drop of water containing the cheek cells.
Wait one minute, and then carefully place a coverslip over the stained check cells.
5. To remove the stain from under the coverslip and replace it with clear water, place a piece of
paper towel at the edge of one side of the coverslip. Then, place a drop of water at the edge of
the coverslip on the opposite side. The stained water under the coverslip will be absorbed by the
paper towel. As the stain is removed, the clear water next to the coverslip on the opposite side
will be drawn under the coverslip. Throw away the paper towel after it has absorbed the stained
water. (The stain makes the cell easier to see.)
6. Place the slide on the microscope. Observe the cheek cells under low power. You many need to
reduce the amount of light coming through the slide in order to see the cells more clearly. Adjust
the diaphragm as needed.
7. Switch to medium power and observe the cheek cells. Draw and label what you see.
8. Carefully clean and dry your slide. Throw away your coverslip. Make sure your microscope is
turned off, is on lower power, and the stage is all the way down. Put the cover back on.
Name _________________________________________________ Score ________
Comparing Plant and Animal Cells
Make sure you label all your drawings. Animal cells should include the following labels: Cell
membrane, Nucleus, and Cytoplasm. Plant Cells should include the following labels: Cell membrane,
(Note: If you cannot see one of the
above organelles, identify which organelles you could not see.)
Cell wall, Nucleus, Cytoplasm, Chloroplast.
Observations
Draw your observations below. When done with all four drawings, answer the questions.
Type of plant cell ______________
Magnification (circle one)
Low Medium
Type of plant cell ______________
Magnification (circle one)
Low Medium
Type of plant cell ______________
Magnification (circle one)
Low Medium
Type of animal cell ______________
Magnification (circle one)
Low Medium
Analysis and Conclusions
1. What is the general shape of the plant cell? ______________________________________
2. What is the general location of the nucleus in the plant cell? _________________________
3. What is the shape of the cheek cell? ___________________________________________
4. What is the general location of the nucleus in the cheek cell? _________________________
5. Why are stains used when observing cells under the microscope? ______________________
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6. Why is it possible to easily collect cells by gently scraping the inside of your cheek?
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7. In general, the surface of a tree has a harder “feel” than does the surface of a dog. What cell
characteristic of each organism can be used to explain this difference?
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8. If you were given a slide containing living cell so fan unknown organism, how would you identify
the cells as either plant or animal?
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It is difficult to say what is impossible, for the dream of yesterday
is the hope of today and the reality of tomorrow.
-Robert Goddard