NAME________________________ DATE_____________ HOUR_____________

PURPOSE: To examine the differences between plant and animal cells

MATERIALS NEEDED: Microscopes, onion sections, toothpicks, forceps, slides, coverslips, Methylene blue, Iodine.

PROCEDURE:

PLANT CELLS: [USE IODINE TO STAIN]

1. Remove a thin layer of onion cells from the inside of the curve on a small slice of onion.
2. Place a drop of water on a slide
3. Put the onion in the drop of water so that it is flat
4. Cover with a coverslip
5. Examine the onion under low power.

**How many layers thick is the specimen?_____________________

6. Make a sketch of what you see on the back.
7. Examine the onion under high power (USE ONLY THE FINE FOCUS UNER HIGH POWER…)
8. Make a sketch of what you see on the back.
9. Remove the slide from the scope. Place a drop of Iodine near one edge of the coverslip. Draw the drop through the specimen by using a paper towel to touch the water at the other end of the cover slip.
10. Reexamine the stained onion tissue under both low and high power.
11. Make a sketch of what you see under both low and high power on the back.

1. Using the broad end of a toothpick, gently scrape the inside of your cheek.
2. Place one drop of water on the second slide.
3. Mix the scrapings on the end of your toothpick into the drop of water. (the water should turn cloudy…)
4. Cover the drop with a coverslip
5. Examine the cells under low and high power.
6. Make a sketch of what you see on the back.
7. Now stain the cells with Methylene Blue using the same technique as above.
8. Reexamine the cells using both low and high power
9. Make a sketch of what you see on the back.

CONCLUSION QUESTIONS:

1. What is the purpose of looking at the cells before we stain them?

 

 

 

 

2. What does the stain do to the cells?

 

 

 

 

3. Describe the differences in the shapes of these two cell types.

 

 

 

 

 

4. Compare the boundaries of a plant cell to an animal cell