Lab – Differences between
Plant & Animal Cells
Plant Cell
Structure
A living cell has a dense nucleus surrounded by a jelly-like cytoplasm. The different structures
within the cytoplasm are called organelles. A cell membrane surrounds the cytoplasm. In plant cells,
cell wall surrounds the cell membrane (plasma membrane). Green plants contain organelles called
chloroplasts; non-green plants (or non-green parts of plants) do not contain chloroplasts. Knowing
the structure of plant cells enables you to understand their life processes. Follow the instructions
below on how to prepare a wet mount of a plant specimen.
1. To prepare a wet mount of the plant specimen, take a section of onion that has already
been sliced. Gently break the onion in half so that the thin, transparent layer of the
onion is exposed. Gently pull off the rest of the transparent layer. Place the onion
membrane on a clean slide, making sure the layer is flat and unfolded.
2. Place a drop of water on the onion membrane. Lower the cover slip over the water,
making sure that you do not trap any air bubbles.
3. Using the proper staining technique, add Lugol’s solution (iodine) to the side of the
cover slip and draw it across the slide with a piece of paper towel.
1. Observe the onion under the LOW POWER OBJECTIVE (4x), when focused and
centered switch to MEDIUM POWER OBJECTIVE (10x) of the microscope. When
focused and centered, switch to the HIGH POWER OBJECTIVE (40x).
2. Draw what you see in the space provided below. You should be able to identify the cell
wall and each cell’s nucleus. Label these in your drawing as you identify it. Make sure
to get the drawing initialed (T.I = Teacher Initials)!
Specimen
______________ T.I.
Magnification:
Next, you will observe green plant cells.
3. Cut a leaf from the tip of an Elodea plant.
4. Prepare a wet mount of the leaf. Do not add any stain!
5. Observe the plant first under the LOW POWER OBJECTIVE (4x) of the microscope,
when focused and centered switch to the MEDIUM POWER OBJECTIVE (10x) of
the microscope. When focused and centered, switch to the HIGH POWER
OBJECTIVE (40x).
6. Draw what you see under HIGH-POWER (400x) in the space provided below. You
should be able to identify the cell’s chloroplasts and the cell wall. Label these in your
drawing as you identify them. Make sure to get the drawing initialed!
Specimen
______________ T.I.
Magnification:
Animal Cell
Structure
Animals have many of the same structures as plant cells. Both animal and plant cells
have a nucleus, a cell membrane, and cytoplasm. Animal cells do not, however, have
cell walls or chloroplasts. In addition, the vacuoles in animal cells are usually smaller
than the vacuoles in plant cells. In the directions that follow, methylene blue stain
will be used. The methylene blue stain highlights the cell structures. Unlike Lugol’s
Iodine satin, methylene blue does not kill cells. It is a vital stain because it permits
the cells to carry on their life processes for a short period of time. Follow the
instructions on how to prepare a stained slide of human cheek cells.
1. Gently scrape the inside of your cheek with the end of a toothpick.
2. Stir the scrapings into a drop of water on a slide.
3. Use the staining method learned previously to stain the cheek cells. Add a drop of
methylene blue to the edge of the cover slip then pull the stain under the cover slip
by touching a paper towel to the opposite edge of the cover slip.
4. Lower the cover slip and examine under the LOW POWER OBJECTIVE (4x) under
the microscope, when focused and centered switch to the MEDIUM POWER
OBJECTIVE (10x) of the microscope. When focused and centered, switch to the
HIGH POWER OBJECTIVE (40x).
5. Draw what you see under HIGH-POWER (400x) in the space provided below. You
should be able to identify the cell membrane and nucleus. Label these in your drawing
as you identify them. Make sure to get the drawing initialed!
Specimen
______________ T.I.
Magnification:
Questions- Answer the following questions in complete sentences.
1. What is the basic structural and functional unit of living organisms?
2. What are the two organelles and their functions that you were able to see in the onion slide?
3. Name and describe the functions of at least two organelles you were able to see in the
Elodea slide?
4. Name three organelles and describe their functions, that are common to both plant and
animal cell?
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5. If you were to examine a plant cell and then an animal cell under the microscope, you would
be able to tell them apart because of a few structures. Name and describe two such
structures, making sure to include which cell (plant or animal) has those structures.
6. Why might a scientist choose to use Methylene blue over Lugol’s iodine to stain a cell?