Name ________________________________________

HUMAN CHEEK 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 coverslip onto the slide

5. Use the SCANNING objective to focus.You probably will not see the cells at this power.

6. Switch to low 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 cell membrane. Draw your cells to scale.

Scanning

Low

High

QUESTIONS

1. Why is methylene blue necessary?

 

2.The light microscope used in the lab is not powerful enough to view other organelles in the cheek cell. What parts of the cell were visible.

 

3. List 2 organelles that were NOT visible but should have been in the cheek cell.

 

4. Keeping in mind that the mouth is the first site of chemical digestion in a human.Your saliva starts the provss of breaking down the food you eat.Keeping this in mind, what organelle do you think would bem numerous inside the cells of your mouth?

 

 

ALTERNATIVE: (Use Skin cells from your wrist instead)

Procedure:
1. Wash the underside of a wrist that will be sampled for epidermal cells with soap and water.
2. Stick a clean piece of clear tape on the underside of the washed wrist.
3. Gently remove the piece of tape from the wrist being careful to avoid getting fingerprints on the tape. A forceps might help to remove the tape and avoid fingerprinting the tape.
4. Place the tape, sticky-side up, on a clean microscope slide.
5. Stain the top, sticky side of the tape with 2 or 3 drops of 1% methylene blue solution.
6. Use a dissecting needle to gently place a cover slip over the sticky tape. Lower the coverslip down onto the tape and then remove the dissecting needle. This should help prevent staining your fingers. Caution: Use methylene blue carefully. It will stain most items including skin, clothing, and table tops.
7. Examine the slide under a microscope. Look for cells with low power first, and then switch to high power for details.
8. Sketch your skin cells and label appropriate parts.