Download Cell Lab

Name ____________________________________
Period _______
Cell Lab
Part 1: The Human Cheek Cell
1. List the 3 parts of the Cell Theory
2. Write a short description of each of the following:
--cell membrane
--cytoplasm
--nucleus
--organelle
--eukaryote
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 LOW POWER to focus. You probably will not see the cells at this power.
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 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 medium and high power. Label the nucleus, cytoplasm, and cell membrane. Draw your cells
to scale.
Medium
High
3. Why is methylene blue necessary?
4. 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?
5. List 2 organelles that were NOT visible but should have been in the cheek cell.
6. Is the cheek cell a eukaryote or prokaryote? How do you know?
Part 2: Onion (Plant) Cells
Procedure:
1.
Obtain a piece of onion from your teacher.
2.
Prepare a wet mount slide of onion skin cells as directed by your teacher.
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Remove the thin, transparent membrane from the inner surface.
Place a flat piece of this membrane on a glass slide.
Cover the membrane with a drop of water and a cover glass.
Be careful to keep the membrane from folding and wrinkling.
Throw your leftover piece of onion in the trash can.
3.
Observe the slide with low, medium and high power magnification.
4.
Is the membrane (skin) composed of one cell or many cells?
5.
What is the general shape of these cells?
6.
Make a sketch of a few cells as seen under high power. Draw and label all structures seen.
7.
Do the cells have a cell wall?
8.
Remove the cover slip, add a drop of methylene blue stain, and replace the cover glass on the membrane.
9.
Observe the slide under both low and high power magnification.
Can you still see the double outer layer, that is, the cell wall?
10.
Why was the stain added?
11.
Can you see a dark, round structure inside the cell?
Do all the cells have the dark, round structure?
This structure is the control center of the cell called the ______________________.
12.
Can you see more than one nucleus inside of the cell?
10. Can you see a lightly-stained, granular area within the cells? This area is called the cytoplasm.
11. Draw a few cells of the stained onion skin as seen under both low and high power. Label structures.
Medium
High