Microbe Madness
Purpose of Lesson
Students will discover the three body shapes of bacteria and will be able to identify
each shape via a model.
Performance Objectives
This lesson fits the grade seven topic, “Cells and Heredity.”
1. Students will compare the different bacterial body shapes and will discover
how protists differentiate from one another in terms of body movement and
obtaining food (meets South Carolina standard 7-2.3)
Materials
To complete this activity, the following materials are needed: pipe cleaners, regular
pom pons, pom pons with sparkly fringe, plastic bags, rulers, and rice.
Description of Activity
The students will travel to six stations around the classroom. At each station, the
students will determine a different bacterial body shape or a different protist
structure for movement.
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Station 1: rod-shaped bacteria represented by rice
Station 2: movement via flagella represented by cork screwed pipe cleaner
Station 3: round-shaped bacteria represented by pom pons
Station 4: movement via cilia represented by sparkly fringe pom pons
Station 5: spiral-shaped bacteria represented by curled pipe cleaners
Station 6: movement via pseudopods represented by the students’ hand in a
plastic bag
Microbe Madness
Station 1
1. The rice represents bacteria with the bacillus shape.
2. Based on the shape of the rice, do you think bacillus means round, rod, or
spiral shaped?
3. All bacteria (round, rod, and spiral shaped species) have their DNA floating in
the cell instead of contained like in plant and animal cells. Do you think
bacterial cells have a nucleus? Why do you think this?
Station 2
1. Place the twisted pipe cleaner between your thumb and index finger and
move your fingers back and forth in opposite directions to make the pipe
cleaner spin.
2. How does the pipe cleaner appear to be moving?
3. A protist, called euglina, uses a tail-like structure, called a flagellum, to move.
How do you think the pipe cleaner is similar to the movement of the
flagellum?
4. What kind of habitat do you think a euglina needs to live in to use its
flagellum for movement?
5. Euglina can make their own food similar to plants. What organelle does a
euglina have to make its own food?
Station 3
1. The pom pons represent bacteria with the coccus shape.
2. Based on the shape of the pom pons, do you think coccus means round, rod,
or spiral shaped?
3. True or false, most bacteria are friendly and are not pathogens.
Station 4
1. Look at the fuzzy pom pon. Each of the sparkly pieces sticking out of the pom
pon represents a hair, which can move. These hairs are called cilia.
2. If the pom pon represents a protist, and the cilia beat back and forth like
oars, what kind of habitat do you think protists with cilia live in?
3. A protist, called paramecium, is covered in cilia. What do you think cilia are
used for?
Station 5
1. The curled pipe cleaners represent bacteria with the spirilla shape.
2. Based on the shape of the curled pipe cleaner, do you think spirilla means
round, rod, or spiral shaped?
3. Other than cell membranes, bacteria cells don’t have any of the organelles
that humans have. Do you think human cells are more complex or less
complex than bacteria cells? How do you know?
4. What kind of organism decomposes most dead plants and animals?
Station 6
1. Place your hand inside the plastic bag at the start of the ruler.
2. Use your fingers to move the bag to the end of the ruler to grab the food
(bacteria, represented by a pom pon).
3. How did the bag move when you moved your fingers?
4. What did the bag do when you grabbed the pom pon?
5. This type of movement is call pseudopod locomotion, and a blob-shaped
protist, called amoeba, uses this type of movement. “Pseudo” means false,
and “pod” means foot. Based on how the bag moved with your fingers, how
do you think an amoeba uses a false foot to move and trap food?