Biology Chapter 7 & 8 Cell Lab
Purpose:
To observe, study ,draw and learn about different types of cells.
Objective:
When you finish this lab you should be able to :
1.
2.
3.
4.
5.
Determine whether cells are prokaryotic or eukaryotic
Prepare a wet mount slide
Describe structure and function of cell organelles
Distinguish plant or animal cells on the basis of their structure
Use a stain to high light certain cell structures
Materials:
Microscope
Slides
Cover Slip
Toothpick
Razor Blade
Dropper
Lens Paper
Iodine Stain
Specimens:
Cork
Onion
Cheek Cells
Elodea
Bacillus Sub
Yeast
Potato
Pepper
Cardiac Cells
IMPORTANT DIRECTIONS FOR DRAWING
1. Make all drawings at the highest magnification possible
2. For each specimen, do not fill the circle (field of view) with cells. Just draw
four cells for each.
3. These four cells must be clear drawings. Take your time and draw what you
see. Cartoons and diagrams will not receive full credit.
4. All drawings must be the size that you see them in the field of view. Do not
draw them larger or smaller than they appear in the microscope.
5. Drawings should include the following information:
1. The magnification used while drawing the cell
2. Appropriately labeled cell structures from the following list:
i. Cell membrane
ii. Cell wall
iii. Chloroplast
iv. Nucleus
v. Cytoplasm
vi. Vacuole
PROCEDURE:
A. Cork Cells: (one drawing)
1. Prepare a wet mount slide of the cork slice. On a clean slide place a drop
of water and your cork specimen. Lay the cover slip on at a 45 degree
angle to avoid trapping air bubbles.
2. View under the highest power possible. Look closely. Draw your
specimen in the ANALYSIS section.
3. Answer questions 1-3.
B. Prokaryotic Cells: Choose two - Bacillus, Streptococcus, Staphylococcus,
Salmonella, (2 drawings)
1. These specimens will be set up for you ahead of time.
2. Draw your specimen in the ANALYSIS section.
3. Answer question 4
C. Pond Water: Filamentous algae and various microorganisms
1. Make a wet mount slide of pond water.
2. Observe under 100x and 400x
3. Draw each in the space provided on the Student Report page using the
highest magnification possible and still see the whole cells. Label your
drawings.
4. Observe the slide Oscillatoria
5. Answer questions
D. Eukaryotic Plant Cells: Onion Cells (2 drawings)
1.
2.
3.
4.
Draw your unstained specimen in the ANALYSIS section.
Answer questions 9 and 10 on onion cells.
Remove the slide from the microscope stage.
Add iodine stain to the cells using the following technique:
a. Place one drop of iodine at the edge of the cover slip
b. Hold a small piece of paper towel on the edge of the other side of
the cover slip. The stain will be pulled under the cover slip and
onto the specimen.
5. Examine the stained onion cells under low and high power. Draw the
stained onion cells on high power and answer questions 9 – 14.
E. Elodea Cells: (one drawing) Elodea is a common pondweed often used to
study photosynthesis and plant cell structure.
1. Remove a young leaf from the tip of a spring of Elodea
2. Prepare a wet mount slide with a cover slip. You will need two or three
drops of water.
3. Observe the Elodea cells on low and medium power. You may not be able
to get to high power because of the thickness of the Elodea leaves.
4. Look for the Chloroplasts; they are the green bodies that are suspended
in cytoplasm. The chloroplasts might be moving along with the
cytoplasm. This is called cytoplasmic streaming.
5. Focus up and down through the leaf. As you slowly move the focal plane
through the leaf count the number of cells layers that come into clear
focus.
6. Draw and label the Elodea cells in the analysis section and answer
questions 15-19.
BACKGROUND INFORMATION FOR PARTS F AND G:
Plastids are cellular organelles of certain Eukaryotes where food or pigments
are made and stored. Chloroplasts are a type of plastid in which the pigment
chlorophyll is stored. For sections F and G you will examine two other types
of plasmids: amyloplasts and chromoplasts.
F. Potato Cell: (one drawing)
1. Place the thin section of potato on a slide
2. Add several drops of water and place on a cover slip.
3. Examine under low power. Center the thinnest part of your potato
section in the field of view.
4. Examine under medium and high power and select the one that gives
you the best view of your potato cells.
5. Turn the fine adjustments back and forth rapidly while looking
through the ocular in order to get a better idea of what the cells look
like.
6. Stain the potato slice with iodine stain using the technique described
above.
7. Return the slide to the stage and view it under medium or high power.
8. Draw the stained potato cell in the space provided. Each intensely
stained structure is called an amyloplast. Label your drawing.
9. Answer questions 20-23.
G. Tomato: (one drawing)
1. Remove the outer skin layer and place the section on a wet mount
slide with a cover slip. You will need a piece of about the diameter of
a pencil.
2. Examine under low and high power.
3. Turn the fine adjustment back and forth rapidly while looking through
the ocular in order to get a better idea of what the cells look like.
4. Draw and label the bell pepper cell under high power in the space
provided. Be sure to note the tiny yellow/green plastids called
chromoplasts.
5. Answer questions 24-26.
EUKARYOTIC ANIMAL CELLS
H. Cheek Cells: (two drawings)
1. The cells that line the inside of your cheek are called epithelial cells.
2. They are constantly being soughed off like the cells of the outer skin.
As a result, some of these cells can be easily and painlessly removed.
3. Put a drop of water on a clean dry slide.
4. To collect some epithelial cheek cells gently scrape the inside of one of
your cheeks with the flat end of a toothpick using an up and down
motion.
5. Transfer your cheek cells from the end of the toothpick by swirling
the end in the drop of water on the slide. Do not spread the water
drop around the slide. Swirl ten or fifteen times
6. Add a cover slip and view under low and high power. The cells will
look like small transparent baggies. The cells tend to clump together
so try to locate one by itself for clear viewing. Note their shape. Draw
the unstained cheek cells under high power in the analysis section..
7. Remove the slide from the stage for staining. Place a drop of iodine
stain under the cover slip with piece of paper towel at the opposite
edge as done above.
8. View under low power. Find one cell and center it in your field of
view.
9. Draw the cheek cell under high power in the analysis section and
answer questions 27-29.
G. Human Blood Smear
1. Obtain a prepared blood slide.
2. Make a drawing based on your observations
QUESTIONS: Answer the following questions on a separate sheet of paper
and staple it to the Student Report Page.
A. Cork Cells:
1. What difference did you notice about the view of the cells near the edge of
your slide compared to the cells near the center of you slice? Explain!
2. What cell structures are apparent when looking at cork cells?
3. Why do the cork ells appear to be empty?
B. Prokaryotic Cells: Bacillus, Streptococcus, Staphylococcus, Salmonella,
4. What were some of the differences you observed?
C. Pond Water and Oscillatoria:
5. What does it mean to oscillate?
6. How did Oscillatoria get its name?
7. Did you add chloroplasts to your drawing of these cells? Explain your
answer.
8. Were the cells in your wet mount sample alive? How could you tell?
D. Onion cells:
9. What did you see through the microscope that show that onion is a plant?
10. What structures can be seen in an unstained onion cell?
11. What differences do you see in the stained and unstained onion cells?
12. Do the onion cells that you examined in this lab have chloroplasts? Why
or why not?
13. Which cell in this organism has chloroplasts? Explain your answer.
14. Of all the cells in part A-D above which ones are prokaryotes?
E. Elodea
15. What structures did you see in both Elodea cells and onion cells?
16. What are the differences between Elodea and onion cells?
17. What is the function of a cell wall?
18. How many chloroplasts are in an average Elodea cell? (Count 3 cells,
calculate the average.)
19. How many cell layers are in an Elodea leaf?
F. Potato Cells:
20. Why did the iodine turn color?
21. What is the name of the cell organelle that changed color with the iodine?
22. What is the function of this structure in the potato cell?
23. Why are potatoes a good source of carbohydrates?
G. Tomato
24. How are the tomato cells different than the Elodea cells?
25. How are the tomato cells similar to potato cells?
26. What structure is visible in the tomato that has not been seen in any other
cells during this lab?
H. Cheek Cells
27. What is different about the unstained and stained cheek cells?
28. How are cheek cells different from the plant cells you have studied?
29. What is the purpose of staining cells?
G. Human Blood Smear