SNC2D
Cells and Tissues
Name: __________________________
EXAMINING PLANT AND ANIMAL CELLS
MATERIALS:
toothpick
light microscope
2 slides and cover slips
onion epithelium
iodine
methylene blue
PROCEDURE AND OBSERVATIONS:
Part 1: Human Cheek Epithelial Cells
1.
2.
3.
4.
5.
6.
7.
8.
9.
Using a toothpick, gently scrape the inside of your cheek to extract a sample of cells.
Place a smear of cells onto the microscope slide. Add a drop of methylene blue.
Place the cover slip over your preparation.
Place the slide on the stage of the microscope.
Turn the nosepiece to low power and focus using the coarse adjustment knob. Rotate to medium
power and focus using the fine adjustment knob until the image is clear.
Rotate to the high power position and focus using the fine adjustment knob.
Using the technique discussed in class, draw the field of view as seen on high power. Label the
following structures on your diagram:
a. Cell membrane
b. Cytoplasm
c. Nucleus
The high power field of view of our microscopes is about 400 m. Estimate the size of one cheek cell.
In the bottom, right-hand corner of your diagram include the following information.
a. The magnification used
b. The name of the stain used
c. The actual size of the specimen (as calculated in #8)
Part 2: Onion Epithelial Cells
1. Obtain a piece of translucent onion epithelium.
2. Using forceps, place the onion epithelium in the centre of the slide. Be sure the epithelium is not
folded or wrinkled.
3. Add a drop of iodine to stain the cells.
4. Repeat steps 4-6 in part 1.
5. Draw the field of view under high power magnification, following the same procedure as above. Label
the following structures:
a. Cells wall
b. Cell membrane
c. Cytoplasm
d. Nucleus
e. Nuclear Membrane
6. Repeat steps 8-9 in part 1.
DISCUSSION QUESTIONS:
1. Why could you NOT see all of the structures of a cell that are show in your textbook?
(1 mark)
2. List a minimum of 4 differences between plant and animal cells.
(4 marks)
3. Do all onion cells look identical (i.e. all the organelles in exactly the same locations)? Explain. (2 marks)
4. (a) Why did you not see chloroplasts in your plant cell (hint: think of where onions grow)?
(b) In which plant cell would you expect to see many chloroplasts? Explain.
(1 mark)
(2 marks)
5. In which animal cell would you expect to see more mitochondria: a muscle or a skin cell? Explain.
(2 marks)
SNC2D
Name: __________________________
Cells and Tissues
Onion Cell/Cheek Cell Lab
Name: _____________________
Diagrams
 Done in pencil
 Accurate labelling
 Accurate drawing (size/shape)
 Included all information
(stain, mag., specimen size, title)
/2
/8
/6
/8
C: _______/24
Discussion Questions
 Accurate
T/I:______/12
Total:_______/36
Onion Cell/Cheek Cell Lab
Name: _____________________
Diagrams
 Done in pencil
 Accurate labelling
 Accurate drawing (size/shape)
 Included all information
(stain, mag., specimen size, title)
/2
/8
/6
/8
C: _______/24
Discussion Questions
 Accurate
T/I:______/12
Total:_______/36
Onion Cell/Cheek Cell Lab
Name: _____________________
Diagrams
 Done in pencil
 Accurate labelling
 Accurate drawing (size/shape)
 Included all information
(stain, mag., specimen size, title)
/2
/8
/6
/8
C: _______/24
Discussion Questions
 Accurate
Total:_______/36
T/I:______/12