Name______________________________
Amoeba
The amoeba is a protozoan that belongs to the Kingdom Protista. The name amoeba comes from
the Greek word amoibe, which means change. (Amoeba is also spelled amoeba.) Protists are
microscopic unicellular organisms that don't fit into the other kingdoms. Some protozoans are
considered plant-like while others are considered animal-like. The ameba is considered an animallike protist because it moves and consumes its food. Protists are classified by how they move,
some have cilia or flagella, but the ameba has an unusual way of creeping along by stretching its
cytoplasm into fingerlike extensions called pseudopodia. (The word "pseudopodia" means "false
foot".) On the coloring sheet, there are several pseudopodia, use a yellow highlighter or pencil to
highlight each of them (color around the outside of them). When looking at ameba under a
microscope, an observer will note that no ameba looks the same as any other, the cell membrane is
very flexible and allows for the ameba to change shape. Color the cell membrane red. Amebas live
in ponds or puddles, and can even live inside people.
There are two types of cytoplasm in the amoeba, the darker cytoplasm toward the interior of the
protozoan is called endoplasm, and the clearer cytoplasm that is found near the cell membrane is
called ectoplasm. (On the coloring, the endoplasm is indicated by the dotted area, and the
ectoplasm by the white area.) Color the endoplasm blue, and leave the ectoplasm uncolored. By
pushing the endoplasm toward the cell membrane, the ameba causes its body to extend and creep
along. It is also by this method that the ameba consumes its food. The pseudopodia extend out and
wrap around a food particle in a process call phagocytosis. The engulfed food then becomes a food
vacuole. There are several food vacuoles on the drawing color each brown. The food will
eventually be digested by the cells lysosomes.
Also visible in the amoeba is the nucleus, which contains the ameba's DNA. Color the nucleus
purple. In order to reproduce the ameba goes through mitosis, where the nucleus duplicates its
genetic material and the cytoplasm splits into two new daughter cells, each identical to the original
parent. This method of reproduction is called binary fission. Another structure easily seen in the
ameba is the contractile vacuole, whose job is to pump out excess water so that the ameba does
not burst. Color the contractile vacuole (labeled vacuole) orange.
During unfavorable conditions, the ameba can create a cyst, this hard-walled body can exist for a
long period of time until conditions become favorable again. At this point it opens up and the
amoeba emerges. Often cysts are created during cold or dry periods where the amoeba could not
survive in its normal condition. Color the cyst green.
Amoebas can cause disease. A common disease caused by the amoeba is called Amoebic Dysentery.
A person becomes infected by drinking contaminated water. The amoeba then upsets the person's
digestive system and causes cramps and diarrhea. A person is most likely to be infected in
countries where the water is not filtered or purified.
Questions:
1. How does an amoeba move? _______________________
2. What structure contains the amoeba's DNA? ________________________
3. When an amoeba engulfs a particle of food a ______________________ is formed.
4. How does an amoeba reproduce? _____________________________
5. During unfavorable conditions, an amoeba forms a ______________________
6. Fingerlike extensions of the amoeba's cytoplasm are called _______________________
7. What disease is caused by the amoeba? ________________________
8. To what Kingdom does the ameba belong? ______________________________
9. How are protozoans classified? _________________________________
10. The word amoeba means ___________________________________
11. The process of engulfing food particles is called __________________________________
12. Is an amoeba considered a plant-like protist or an animal-like protist? ______________________
