Cell Microscopy
Name : ________________
Date: _________________
The Human Cheek Cell ~ An Example of an Animal Cell
Procedure:
1. Put a drop of methylene blue on a slide. Caution: methylene blue will stain clothes and skin.
2. Gently scrape the inside of your cheek with the flat side of a toothpick. Scrape lightly.
3. Stir the end of the toothpick into the stain and throw the toothpick away.
4. Place a cover slip onto the slide
5. Use the lowest objective to focus.
6. Switch to medium power. Cells should be visible, but they will be small and look like nearly clear purplish
blobs. If you are looking at something dark, dark purple, it is probably not a cell
7. Once you think you have located a cell, switch to high power and refocus.(Remember, do NOT use the
coarse adjustment knob at this point)
---Sketch the cell at low and high power. Label the nucleus, cytoplasm, and plasma membrane. Draw your
cells to scale.
Low
3. Why is methylene blue necessary?
4. What organelles do you think you see?
Medium
High
The Onion Cell ~ An Example of a Plant Cell
Procedure:
1. Put a drop of iodine on a slide. Caution: iodine is hazardous & will stain clothes and skin.
2. Prepare a water wet mount of onion skin. Do this by using your fingernail to peel off the inside layer of a
onion bulb. The layer must be almost transparent.
3. Make sure that the onion layer is laying flat on the glass slide and is not folded.
4. Observe the onion cells under low and high power magnification. Identify as many organelles as possible.
5. Repeat steps 1 through 3, only this time use an iodine stain instead of water.
---Sketch the cell at low and high power. Label the nucleus, cytoplasm, plasma membrane, and cell wall. Draw
your cells to scale.
Low – no iodine
Low with iodine
What organelles were easily seen in the unstained onion cells?
What organelles were easily seen in cells stained with iodine?
High with iodine