If you missed it in class you must go online and complete the virtual: lab

The Human Cheek Cell: / Name ______
1. Take time to review the parts and proper use of microscope.
2. Describe or define each of the following
a--cell membrane
b--cytoplasm
c--nucleus
d--organelle / 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 in the stain and throw the toothpick away.
4. Place a coverslip onto the slide
5. Use the low objective to focus. You probably will not see the cells at this power.
6. Switch to the scanning (medium) objective. (Remember, do NOT use the coarse adjustment knob at this point) Cells should be visible, but they will be small and look like nearly clear purplish blobs. If you are looking at something very dark purple, it is probably not a cell
7. Once you think you have located a cell, switch to high power and refocus only if you can…DO NOT FORCE IT! (Remember, do NOT use the coarse adjustment knob at this point)
3. Sketch the cell at low and high power. Label the nucleus, cytoplasm, and cell membrane on each. Draw your cells to scale.
Low Power
/ Scanning (Medium) Power

4. Why is methylene blue necessary?
5. 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 (refer to what you labeled above).
6. List 2 organelles that were NOT visible but should have been in the cheek cell.
7. Is the cheek cell a eukaryote or prokaryote? How do you know?

Analysis/ Conclusions

1. Why do objects have to be thin to be visible using a compound light

microscope?

2. Why do you see LESS of an object on high power?

3. You just placed the slide on the stage, the objective you are going to

use FIRST should be the ______power objective lens so that

you do not crack the slide.

4. If the specimen is barely visible, you would like more light to come

through the stage, you would turn the ______.

5. To calculate total magnification, you multiple the power of the

eyepiece (10) times ______.

6. Why should you NEVER move the coarse adjustment knob when you

are on high power?

7. If an object appears to be moving down and to the right while looking

through the microscope, in what direction is it really moving?

8. What are the steps in preparing a wet-mount slide? (Hint: Look at the cheek cell directions)

QUICK REVIEW-

1. List the 3 parts of the Cell Theory:

2 Write down the characteristics of ALL LIVING organisms. Go back to your notes in Unit 1 if you need help.