Foundations of Biology
Fisher/Schultz
Ch. 7 LAB: Plants, Animals, and other Weird Cells
FQ:
Do cells change in response to their environment?
Introduction:
In this lab, you will have the opportunity to prepare samples and view four different types
of cells. You will view:
1. An animal squamous (scaly) cell by taking a sample from your cheek.
2. A root cell by looking at an onion.
3. A typical plant cell by looking at the leaf of a water plant called an Elodea.
4. A “stinging” cell, called an “idioblast” that comes from the plant Dieffenbachia.
You will record your observations in two ways: 1. By writing short descriptions 2. By
drawing pictures.
Materials:
Microscope
Slide, coverslip
Toothpick
Methylene Blue
Red Onion
Droppers
Salt Water
Distilled H20
Elodea (aqua plant)
Mortar, pestle
Dieffenbachia (plant)
Procedure
Cell A: Animal Cell Instructions
1. Obtain a slide, cover slip. Clean both the slide and the cover slip.
2. Drop one small drop of water on the slide.
3. Using a clean toothpick, gently scrape the toothpick inside your mouth along the cheek wall.
4. Smear the toothpick across the slide where the water drop is.
5. Add one drop of methylene blue.
6. Carefully drop the cover slip over your sample and gently press on one corner of it.
7. Carefully wick away the excess moisture (teacher will show you how to wick).
8. Observe under low and high powers, recording(writing) your observations.
9. Make drawings under high power. Label the cell parts (cell membrane, cytoplasm, and
nucleus) in your drawings that you can see. If you see additional parts label them.
10. Appropriately dispose of your tooth pick and wicking materials.
11. Clean and dry both slide and cover slip.
Example of a cheek cell:
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Cell B: Onion Cell Instructions:
1. Clean and dry your slide and cover slip.
2. Obtain a very thin section of onion from your teacher. Peel a single outer purple layer of the
section given to you and place it on the slide so that it is flat.
3. Place one drop of water on the onion.
4. Place the cover slip over the sample and press lightly on one corner to remove the air bubbles.
5. Observe the onion on both medium and high powers, write quality observations and draw
under high power.
6. Label all of the cell parts in each drawing that you can see.
7. While you are watching on medium or high power, add 2-3 drops of salt water to the side of
your cover slip and wick it through by using a piece of paper towel on the opposite side of the
cover slip.
8. Wait 3 minutes, record your observations and draw what you now see. Label that part(s) that
you could not see before.
9. Add several drops of distilled H2O to the slide. Wait 3 minutes. Record you observations.
10. Appropriately discard the sample, clean and dry both cover slip and slide thoroughly.
Example of an onion cell:
Cell C: Elodea plant Instructions:
1. Clean and dry the slide and cover slip.
2. Get a small leaf of the Elodea.
3. Put a drop of water on your slide and set the leaf on it.
4. Use a cover slip to help flatten the leaf; push gently on the corner of the slip to try to remove
any air bubbles.
5. Observe the outer edge of the leaf. Record in your journal any evidence you see that some
cells are specialized (different from other elodea cells).
6. View under low and high power. After several minutes under the light, make quality
observations and drawing under high power. Label the parts of the cell in your drawing that you
can see.
7. After several minutes under the light you should be able to see the “cytoplasmic streaming”—
the movement of chloroplasts around the cell. Label the parts of the cell in your drawings that
you can see and describe what the chloroplasts are doing.
8. Appropriately discard your leaf sample, clean and dry your slide and cover slip thoroughly.
Elodea under low power
Elodea under high power
Foundations of Biology
Fisher/Schultz
Cell D: Idioblast (Dieffenbachia plant)
A
B
Instructions for the Lab:
1. Obtain a mortar and pestle and a small chunk (less than 1 square inch) of the plant.
2. Put 15 drops of water in the mortar and add the piece of plant.
3. Crush and mix the plant for 2-3 minutes.
4. Let the pestle rest on the mortar (at a slight angle) for 2 minutes.
5. With a dropper, put 1-2 drops of mixture from the bottom of the mortar on a slide with a cover
slip.
6. Examine under scanning objective power until you find an idioblast, then work up to low &
high power.
7. If most of our idioblasts are unbroken, mash the stuff in the mortar some more and prepare a
new slide.
8. Record quality observations and draw what you see out of each slide set, labeling the parts.
9. Carefully clean, wash, rinse, and dry the mortar, pestle, slide, and cover slip.
10. When you are finished with all four cells, put the microscope to “bed” in the proper manner.
Foundations of Biology
Fisher/Schultz
DATA
A. Animal Cell
Shape
Cell Parts Present
Unique Feature
B. Onion Cell
Shape
Cell Parts Present
Unique Feature (movement?)
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Fisher/Schultz
C. Elodea
Shape
Cell Parts Present
Unique Feature (movement?)
D. Idioblasts (Dieffenbachia)
Shape
Cell Parts Present
Unique Feature (What happens)
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Analyze and Conclude
1. Describe the differences between the Elodea and the onion.
2. Hypothesize/explain why there are these differences (as described in #1), even though
they are both plant cells. (Hint: Chloroplasts do photosynthesis)
3. Describe the differences between typical plant and animal cells.
4.Describe the differences between the idioblast cells and normal plant cells. What is it
about idioblasts that make them so special?
5. When observing the Elodea, you should have noticed that the Chloroplasts were moving
around the inside of the cell. This is called cytoplasmic streaming. Hypothesize why it
took several minutes for you to notice that happening. Hint: It is tied to the job of the
chloroplast.
6. Hypothesize why there is a difference in the cell structures between plants and animals
and explain why those differences are important for the way the different organisms live.
Foundations of Biology
Fisher/Schultz