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Name: _______________________________
Ch 7: Cell Investigation Lab
Ms. Czuprynski
INTRODUCTION:
During this lab we will be examining and comparing two types of cells: animal and plant cells. The animal cell will
come from your own cheek and the plant cell will be from a common house plant. In order to better view the cells
we will use a stain called methylene blue. This stain darkens the parts within a cell making them more visible under
the microscope. BE CAREFUL when handling this stain because it will stain your clothes.
Cells form the basic units of life that carry out all of the functions of living organisms at the molecular level.
Human cheek cells are flat epithelial cells that are constantly being replaced. Their main job is to secrete digestive
enzymes that are necessary for chemical digestion that takes place in the mouth.
Plants and animals both have a layer of tissue called the epidermal layer. Plants have special pores called
stomata to allow passage of material. The stomata pores are surrounded on both sides by jellybean shaped cells
called guard cells. Unlike other plant epidermal cells, the guard cells contain chlorophyll to do photosynthesis.
This allows the cells to expand/ contract to open or close the stomata. Guard cells also close when dehydrated.
This keeps water in the plant from escaping. The opening or closing of guard cells can be viewed in a microscope
by adding different water concentration to the leaf tissue. Most stomata are on the lower epidermis of the leaves
on plants (bottom of the leaf).
PRE-LAB QUESTIONS:
1. What is the purpose of this lab?
2. What is the main function of cheek cells?
3. What are stomata and where are they found on the plant?
4. Why is it necessary to use methylene blue in this lab?
MATERIALS:
 Animal Cell

Cellophane Tape

Lens Wipes
(Cheek)

Slide

Dropper
Plant Cell (Leaf

Cover Slip

Beaker
Epidermis)

Toothpick

Water
Clear Nail Polish

Paper Towels


PROCEDURE:
A. Part 1 - Procedure for cheek cells
□ 1. Clean slide and cover slip with lens wipe.
□ 2. Place 1 drop of water in the center of the slide.

Methylene Blue
Stain

Colored Pencils
□ 3. Gently scrape the inside of your cheek with the edge of the toothpick.
Paper
Towel
□ 4. Gently place the toothpick with cheek cells in the water on the slide.
□ 5. Place 1 drop of methylene blue stain in the water.
□ 6. Place cover slip on top of the water / cheek cell / stain mixture.
□ 7. Clear away some of the stain (see diagram on the right):
□ a. Place paper towel on one side of cover slip (touching the cover slip).
□ b. The stain will be “pulled” into the paper towel (capillary action).
□ c. Throw away paper towel
Cover
Slip
□ 8. Place slide on microscope on the lowest power objective. Focus using the course and fine adjustments.
□ 9. Write 2 qualitative observations about the cells on LOW POWER.
□ 10 Change to medium power objective and draw and color the cheek cells.
□ 11. Write 2 qualitative observations about the cells on MEDIUM POWER.
□ 12. Change to high power objective and draw and color the cheek cells.
□ 13. Write 2 qualitative observations about the cells on HIGH POWER.
B. Part 2 - Procedure for plant cells
□ 1. Clean slide and cover slip with lens wipe.
□ 2. Paint a thick patch (at least one square centimeter) of clear nail polish on the underside of the leaf
□ 3. Allow the nail polish to dry completely.
□ 4. Tape a piece of clear cellophane tape to the dried nail polish patch.
□ 5. Gently peel the nail polish patch from the leaf by pulling on a corner of the tape and "peeling" the fingernail
polish off the leaf. This is the leaf impression you will examine.
□ 6. Tape your peeled impression to a very clean microscope slide.
□ 7. Use scissors to trim away any excess tape.
□ 8. Place slide on microscope on the lowest power objective. Focus using the course and fine adjustments.
□ 9. Write 2 qualitative observations about the cells on LOW POWER.
□ 10 Change to medium power objective and draw and color the cheek cells.
□ 11. Write 2 qualitative observations about the cells on MEDIUM POWER.
□ 12. Change to high power objective and draw and color the cheek cells.
□ 13. Write 2 qualitative observations about the cells on HIGH POWER.
ANALYSIS QUESTIONS:
1. The light microscope used in the lab is not powerful enough to view other organelles in the cheek or plant cell.
What parts of the cell were visible?
2. List 2 organelles that were NOT visible in the cheek cell and their function.
3. List 2 organelles that were NOT visible in the plant cell and their function.
4. Keeping in mind that the mouth is the first site of chemical digestion in a human. Your saliva starts the process
of breaking down the food you eat. Keeping this in mind, what organelle do you think would been numerous
inside the cells of your mouth? (Use Chapter 7.3 to help answer this)
5. Compare and contrast the cheek cell and the plant cell. What are two ways they are similar and two ways they
are different.
Name: ___________________________
Cell Investigation Lab
ANIMAL CELL
Low Powered Objective
Total Magnification:__________
Medium Powered Objective
Total Magnification:__________
Observations
High Powered Objective
Total Magnification:__________
Name: ___________________________
Cell Investigation Lab
PLANT CELL
Low Powered Objective
Total Magnification:__________
Medium Powered Objective
Total Magnification:__________
Observations
High Powered Objective
Total Magnification:__________