Cell lab: Prokaryotes (bacteria) and Eukaryotes (Protist, Plant, fungi, and animal cells)
Name: ______________
Date: _______________
Period: ______________
INTRODUCTION
We have learned about prokaryotes and eukaryotes and their characteristics. Bacteria belong to prokaryotes
and exist everywhere, including our body. Today, we will take bacteria from our teeth and observe them.
Eukaryotes are much bigger than prokaryotes and have more complex structures. Protists, plants, animals,
and fungi belong to eukaryotes. While protists are single-celled organisms, plants, animlas, and fungi are
usually multi-celled organisms. (There are some single-celled fungi which are exceptions.) We will observe
cells of protists, animals, fungi, and plants today. As for protists, we will observe the Paramecium which
lives in fresh water. We will look at leaves of Elodea for plants, our cheek cells for animals, and bread mold
for fungi. You have to draw your observations and compare different cells that belong to different groups.
HYPOTHESIS
You will observe Elodea leaf cells and cheek cells from your mouth. Which cells do you think are larger?
Why?
_______________________________________________________________________________
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OBJECTIVES
By the end of this lab, students should be able to
-Explain the difference between prokaryotes and eukaryotes.
-Explain the difference between plant cells and animal cells.
-Observe cells using microscopes.
-Describe characteristics of plant cells and animal cells through observation using microscopes
-Explain the effect of size of cells on their function
MATERIALS
Microscope slides
Goggles
Forceps/ tweezers
Cover slips
Elodea leaf
Cheek cells
Idodine or 0.1% methylene blue stain
Toothpick
Compound microscope
Water
Paramecium stock solution
Slowing solution (1 teaspoon of Polyethylene oxide and 3 ounces of warm water)
Bread mold (prepared by the teacher in advance)
SAFETY
-No food or drink is allowed during the lab.
-Wear goggles when dealing with chemicals or glassware.
-When you hold or carry a microscope, use both hands and be careful so you do not drop it.
-Methylene blue can stain clothes and skin, so be careful.
-Iodine is toxic.
-When you use a microscope, always start at low power and switch to high power.
PROCEDURES
Prokaryotes:
Bacteria in your tooth plaque
1. Add a drop of water to a clean slide.
2. Scrape plaque from your tooth using a toothpick.
3. Mix the plaque with the drop of water.
4. Let the slide dry.
5. Add a drop of stain and wait for three minutes.
6. Rinse the slide.
7. Observe the plaque using a microscope and draw your observation.
8. Make sure you write the correct magnification.
9. Measure the size of one cell (length and width).
10. Label different types of bacteria. (Rod-shaped or sphere-shaped.)
Eukaryotes:
Paramecium
1. Add a drop of paramecium stock solution to a slide.
2. Add a drop of slowing solution to the slide.
3. Observe paramecium and draw your observation.
4. Make sure you write the correct magnification.
5. Measure the size of one cell (length and width).
6. Label cilia, and label organelles inside the body if you can distinguish them.
Elodea leaf
1. Remove a leaf from plant Elodea.
2. Make a wet mount of the leaf.
3. Add a coverslip.
4. Observe the leaf using a microscope and draw your observation.
5. Make sure you write the correct magnification.
6. Measure the size of one cell (length and width).
7. Label cell wall, cytoplasm, and chloroplasts.
Cheek cell
1. Gently scrape the inside of your check with a toothpick
2. Put the check cells on a microscope slide.
3. Put a drop of iodine or 0.1% methylene blue stain on the slide.
4. Observe the cheek cells using a microscope and draw your observation.
5. Make sure you write the correct magnification.
6. Measure the size of one cell (length and width).
7. Label nucleus, cell membrane, and cytoplasm.
Bread mold
1. Use a toothpick to scrape bread mold and put it on a microscope slide.
2. Mix the mold with 0.1 methylene blue stain and add a coverslip.
3. Observe the mold using a microscope and draw your observation.
4. Make sure you write the correct magnification.
5. Measure the size of one cell (length and width.).
6. Label hyphae and other organelles you can observe.
OBSERVATION/DATA
Prokaryotes:
Drawing of plaque from your teeth: Label different types of bacteria. (Rod-shaped or sphere-shaped.)
Magnification: _______________________
The size of one cell: ___________________
Eukaryotes:
Drawing of paramecium: Label cilia, and label organelles inside the body if you can distinguish them.
Magnification: _______________________
The size of one cell: ___________________
Drawing of the Elodea leaf cells: Label cell wall, cytoplasm, and chloroplasts.
Magnification: _______________________
The size of one cell: ___________________
Drawing of the cheek cells: Label cell wall, cytoplasm, and chloroplasts.
Magnification: _______________________
The size of one cell: ___________________
Drawing of bread mold: Label hyphae and other observable organelles.
Magnification: _______________________
The size of one cell: ___________________
Fill out the following table based on your observations.
Prokaryotes
Plaque from your
teeth (bacteria)
Size
Color
Shape
Other
characteristics
that are unique
to each group
Paramecium
(protist)
Eukaryotes
Elodea cell
Cheek cell
(plant)
from the inside
of your mouth
(animal)
Bread mold
(fungi)
ANALYSIS QUESTIONS
1. Which cells (between Elodea and cheek cells) are larger? Does this support your original hypothesis?
2. From your observations, what are the main differences between Elodea cells and cheek cells (plant
cells and animal cells)? Describe at least two differences.
3. What are the functions of chloroplasts?
4. From your observations, what are the main differences between prokaryotes and eukaryotes?
Describe at least two differences.
5. Between prokaryote and eukaryotes, which group do you think evolved first? Why? Support your
reasons using what you observed.
Notes: This lab is group work and three to four students will work together. You can discuss analysis
questions, but SHOULD NOT COPY OTHERS’ ANSWERS. Even though you are allowed to work
together and discuss questions, you should write your own answers!
Adapted and modified from Rainis, K.G. (2005). Cell and microbe science fair projects: Using microscopes, mold,
and more. Berkeley Heights, NJ: Enslow Publishers, Inc.