Plant & Animal Cell LAB

BIOLOGY 067
CELLS: THE BASIC UNITS OF LIFE
Purpose:
To identify and observe cells; onion, moss and human.
To recognize the differences in structure between these cells.
Materials: microscope iodine stain (Lugols’s solution)
slides
methylene blue
cover glasses
medicine dropper
onion bulb (Allium sp) forceps
moss leaves (Mnium sp.) scissors
cheek cells
Kimwipes
toothpick
Methods: 1. The epidermis of the onion is ideal for cell study because it is
composed of a single layer of cells.
Cut an onion lengthwise. Remove a thick scale and peel the delicate
transparent tissue from the inner surface. Prepare a wet mount slide. Stain
with iodine (Lugol’s solution). Examine the cells under the microscope.
If a cell is deep then you will be able to focus with the fine
adjustment at several levels in the cell when you view them at high powers.
Try this with the onion cells.
Describe the cells (colour, shape, depth, organization, appearance of
contents etc.)
Estimate the size of one cell.
Draw the cells at 400x or 1000x. Label the cell (at least cell wall,
plasma membrane, nucleus and cytoplasm should be labelled).
2. The moss leaves are also one layer of cells thick.
Prepare a wet mount slide with a moss leaf. One whole leaf should
be used. Do not stain these cells.
Examine the leaf under the microscope.
Use the fine adjustment to observe the cells at various depths.
Observe the small, oval, green bodies that appear in the cells. These
are the chloroplasts.
Describe the cells. Estimate the size of one cell.
Draw the cells at 400x or 1000x. Label the cells (at least cell wall,
plasma membrane, chloroplasts and cytoplasm should be labelled)

3. By gently scraping your cheek, you will release several cheek cells.
Gently scrape the inside of your cheek with a clean toothpick.
Prepare a wet mount slide with the material that you have scraped. Add
methylene blue stain.
Examine the cells with a microscope.
Describe the cells. Estimate the size of one cell.
Draw the cells at 400x or 1000x. Label the cell (at least plasma
membrane, nucleus and cytoplasm should be labelled).
Results:
Conclusions:
Your drawings and observations are your results.
Compare the cells you observed: discuss similarities and differences among
the three cells using at least four characteristics.
What differences might be related to plant vs. animal cell structure?