Protist Lab
Background:
The Protist Kingdom is made up of a variety of unicellular organisms, which are sometimes referred to as
protozoans or algae. Some of these one-celled organisms are capable of making their own food by
photosynthesis. Others have developed methods of ingesting food by means of specialized organelles.
(Some protists make their own food and eat other food.) Protists have a variety of appearances and methods
of locomotion.
Materials:
Cultures of: Paramecium and Euglena, Prepared slide of Amoeba, Microscopes, Slides, Cover slips,
Droppers, and Methyl cellulose (Proto Slo)
Section I: The Amoeba
Amoeba are large, colorless unicellular organisms with no definite shape. They move slowly by extending
their pseudopods (projections of the cell membrane pushed forward by the cell’s cytoplasm).
1. Use the dropper in the amoeba culture to get a drop out of the container, and place it on a microscope
slide.
2. Find the amoeba under scanning power and observe it. Reduce the light by adjusting the diaphragm.
(You may want to use low power so that the amoeba fills up a large portion of the field of view. This will
depend on the size of the amoeba that you are observing.)
3. Sketch the amoeba on the circle in Diagram 1a in your lab journal (USING LOW POWER).
4. The amoeba’s contractile vacuole appears as a clear circle. Look at your amoeba and try to find what
looks like a small bubble inside.
5. To eat, an amoeba uses its pseudopods to trap and engulf food through a process called phagocytosis.
When it has eaten, a food vacuole is formed. Look at the amoeba in the microscope, and try to find a
vacuole with material inside. (Do not confuse it with the nucleus, which is the largest dark object in the
amoeba.)
6. On the Diagram 1b of the amoeba, label the following: pseudopods, nucleus, cell membrane,
cytoplasm, contractile vacuole and food vacuole.
Section II: The Paramecium
Are medium sized, clear, slipper-shaped organisms that move quickly by cilia.
1. Use the dropper in the paramecium culture to get a drop of “scum” out of the container, and place it on a
microscope slide. Add one drop of methyl cellulose on top of the paramecium (this is a “syrup” to slow
down the organisms). Place a cover slip on top of the mixture.
2. Find a paramecium under scanning power and observe it. Then, change to low power to see the details of
the paramecium better. Reduce the light by adjusting the diaphragm. You may need to move the slide to
keep the paramecium in the field of view.
3. Carefully draw the paramecium on the circle in Diagram 2a in your lab journal (USING HIGH POWER).
4. The amoeba and paramecium have contractile vacuoles, which are structures that control osmotic
pressure inside of the cell. It appears as star shaped structures at each end. Try to find the contractile
vacuoles in your specimen.
5. In order to eat, a paramecium collects food in its oral groove. When it has eaten, a food vacuole is formed.
Look at the paramecium in the microscope, and try to find a vacuole with material inside. (Do not confuse
it with the nucleus, which is the largest dark object in the paramecium.)
6. On Diagram 2b, label the following: cilia, nucleus, cell membrane, cytoplasm, contractile vacuole and
food vacuole.
7. Wash the paramecium down the drain. Wash and dry the slide and cover slip.
Section III: The Euglena
Euglena are small, green, oval-shaped organisms that move quickly by flagellum.
1. Use the dropper in the euglena culture to get a drop out of the container, and place it on a microscope
slide. Place a cover slip on top of the drop.
2. Find euglena under low power and observe them. Shift to high power, and get a closer look.
3. Carefully draw a few euglena on the circle in Diagram 3a in your lab journal (USING HIGH POWER).
4. The euglenas’ chloroplasts appear as green objects inside the cells. Euglenas make their own food by
photosynthesis, but may also eat if they choose to.
5. On Diagram 3b, label the following: flagellum, nucleus, cell membrane, & cytoplasm
6. Wash the euglenas down the drain. Wash and dry the slide and cover slip.
LAB JOURNAL FORMAT
Title: _______________
Materials:
Diagram 2 a & b
Diagram 1 a & b
Diagram 3 a & b
Analysis questions #1 - 10
CUT OUT & PASTE INTO YOUR LAB JOURNAL
Diagram 1a: Amoeba
Diagram 1b: Amoeba (label the structures listed in #6)
Diagram 2a: Paramecium
Diagram 2b: Paramecium (label the structures listed in #12)
Diagram 3a: Euglena
Diagram 3b: Euglena (label the structures listed in #18)
Analysis Questions
Answer the following questions in your lab journal using complete sentences.
1. Which of the organisms that you observed are autotrophs?
2. List the structures that all 3 organisms have in common with each other.
3. What is the function of the contractile vacuole?
4. How do Amoeba eat?
5. How do Paramecium move?
6. How do Euglena move?
7. Why did we use methyl cellulose on the slides with Paramecium?
8. Where does the Paramecium’s food go after it is eaten?
9. What do the chloroplast in the Euglena do?
10. What is the name of the process that Amoeba use to engulf (& consume) their food?