Download Cell and Microscope Lab

Biology
Name______________________________
Per.________
The Cell and Microscope Lab
Purpose:
Materials:
Microscope
Prepared slide of letter “e”
Elodea Leaf
Your cheek cells
Methylene Blue Stain
Blank Slides and Cover slips
Prepared Slide of colored threads
Onion cells
Iodine stain
Procedure:
Part 1: The letter “e”
1. Carefully bring your assigned microscope back to your lab area making sure to
carry it properly.
2. Use lens tissue and cleaner to wipe lens and slides.
3. Plug in your microscope
4. Obtain a prepared slide of the letter “e” and place it on the stage. Secure it with
the stage clips and center it over the light source.
5. Find and focus the letter “e” under LOW power. ANSWER QUESTION #1.
6. Draw and label the letter “e” as per teacher instructions under low power.
7. Make sure the “e” is in the center of the field of view. Then switch to medium
power.
8. Find, focus and center the letter. Draw and label the “e” under medium power.
9. Switch to high power. Find and focus using the fine focus knob ONLY. Answer
QUESTION #2.
10. Draw and label the letter “e” under high power.
Part 2: Colored Threads
1. Obtain a slide of colored threads. Find the center of the crossed threads under low
power.
2. Observe the center of the threads under medium power. ANSWER QUESTION
#3.
3. Draw and label the colored threads under MEDIUM and then HIGH power.
Part 3: Preparing a wet mount slide-Elodea Leaf
1. Prepare a slide of the elodea leaf as per teacher instructions.
2. Scan the slide to find edge of the leaf.
3. Observe under low power. Then switch to medium power. Answer QUESTION
#4 and #5.
4. Make a Drawing of a “Group of 10 Elodea Cells” under 10X. Make each cell 2.5
cm long.
5. LABEL: CELL WALL, CYTOPLASM, and CHLOROPLAST
6. Now select a SINGLE cell that shows its contents clearly. Move it to the center of
the microscope field.
7. Turn to High power and carefully examine the cell.
8. Make a drawing of a “ Single Elodea Cell” under 43X. The cell should be 5 cm
long.
9. LABEL: CELL WALL; CYTOPLASM and CHLORPLAST
Part 4 - Plant Cells- Onion Cells
1. Cut a small cm square from the tissue. Mount the tissue in a drop of IODINE.
(Try not to wrinkle the tissue) Place a cover slip on top and observe under LOW
POWER
2. Answer question #6
3. Make a Drawing of a “Group of 10 Onion Cells” under 10X. Make each cell 2.5
cm long.
4. LABEL: CELL WALL, NUCLEUS, CYTOPLASM
5. Now select a SINGLE cell that shows its contents clearly. Move it to the center of
the microscope field. Answer question: #7
6. Turn to High power and carefully examine the cell.
7. The clear middle area of the cell is called the Central Vacuole. You should be able
to see the nucleus clearly. Inside the nucleus the darker, smaller circle is called the
Nucleolus. The nucleus is surrounded by the Cytoplasm. Answer questions 8 and
9
8. Make a drawing of a “ Single Onion Cell” under 43X. The cell should be 5 cm
long.
9. LABEL: CELL WALL; NUCLEUS; NUCLEOLUS; CYTOPLASM
Part 5 - Animal Cells- Cheek Epithelial Cells
1. Now its time to “sacrifice your body to science. You will be using some of your
own cheek cells for this part of the experiment. You will therefore be able to
compare epithelial (skin) tissue from both plans and animals.
2. Place a drop of methylene blue stain on a clean microscope slide. Have a cover
slip ready.
3. GENTLY scrape the inside of your cheek with a clean, flat toothpick. (If you can
see: a) blood, b) a hunk of meat on the toothpick or c) the end of the toothpick
from the outside of your cheek, you have gone too deep with the toothpick.) 
4. Stir the end of the toothpick with your cells into the drop of methylene blue. PUT
THE TOOTHPICK IN THE TRASH. Add a cover slip to the slide.
5. Examine under 10X. You should find a small group of cells and hopefully several
individual ones. Focus on the outer edge of the cytoplasm and Answer Questions:
10 and 11.
6. Make a drawing of “ A Group of 10 Cheek Epithelial Cells.” Each cell should be
2.5cm in diameter.
7. LABEL: CELL MEMBRANE (not wall), CYTOPLASM AND NUCLEUS.
8. Center one of the individual cells (one that is NOT folded in any way) in the field
of view and switch to high power. Answer Questions: 12 and 13.
9. Make a Drawing of “ Single Cheek Cell” under 43X
10. LABEL: CELL MEMBRANE; NUCLEUS; AND CYTOPLASM
Analysis Questions: Please change the font or bold face your answers after the question
1. How does the direction of the letter “e” look under the microscope compared to
the actual object on the slide?
2. Why must you only use the fine focus while under high power?
3. What is the order of the colored threads from top to bottom?
4. What is the shape of the plant cells you see?
5. Why do leaves have green pigments in their cells?
6. What is the shape of the onion cells?
7. Why did you move the onion cell to the center of the field
8. What color is onion cell’s the cytoplasm?
9. How can you tell that the onion cells have a cell wall?
10. Where is the cell membrane found on the cheek cell?
11. How does the thickness of the edge of the cheek cell compare to the cell wall of
the plant cell?
12. Describe the shape of the cheek cells.
13. Compare and Contrast the Onion, Elodea and Cheek cells. You may make a chart.
CER: