Download Lesson 7.2 – Bacteria Study Guide 1. What is bacteria? • A simple

Lesson 7.2 – Bacteria
Study Guide
1. What is bacteria?
 A simple, one-celled organism that has no nucleus.
2. Describe the structure of a bacteria cell.
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Genetic material – used to reproduce
Cytoplasm – jelly like fluid
Membrane – allows materials to enter, leave
Cell Wall – give shape and protects
Flagellum – help bacteria to move
Ribosome – make proteins
3. How do bacteria move?
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Bacteria can move through water using flagella. A flagellum is a whip-like that
propels the bacteria. Bacteria can have one, many, or no flagella.
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Bacteria can be carried by wind, by water currents, or by being picked up by
other organisms.
4. What shapes do bacteria have?
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rod, spiral, round
5. How do bacteria obtain energy?
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Some bacteria have chlorophyll and are able to make their own food. We call
these autotrophs.
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Most bacteria feed of dead, organic matter. These are hetereotrophs. We also
call these bacteria decomposers, since they decompose dead material into
nutrients that can be recycled.
6. How do bacteria reproduce?
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The bacteria grow larger.
The bacteria makes a copy of its genetic material.
The bacteria divides in half.
Two daughter cells are formed
The process repeats itself.
7. What kind of reproduction is this called?
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asexual reproduction
8. How do bacteria survive conditions when food and water become scarce?
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Bacteria form into endospores.
9. Describe an endospore.
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The bacteria forms a thin, tough membrane around its genetic material.
The bacteria becomes dormant.
When the conditions improve, the bacteria reactivates.
The endospore protects the bacteria from extreme heat, cold, or lack of water.
The bacteria can survive for many years as an endospore.
10. Are bacteria harmful or helpful?
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Most bacteria are harmless. Some are helpful. A few can be harmful.
11. Describe how bacteria can be helpful.
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Bacteria are nature’s decomposers. They break down dead matter into nutrients that
can be recycled.
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Some bacteria live in roots of plants and the soil. These bacteria change nitrogen in
the air into fertilizers for plants.
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Micro-organisms feed off of bacteria. Bacteria form the bottom of the food chain.
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We use bacteria to make some foods: cheese, yogurt, sour cream, vinegar,
soy sauce, sour kraut, kimchee
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Cities use bacteria to break down sewage into water that is safe for the environment.
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Bacteria can breakdown the oil from an oil spill.
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Bacteria live in people’s “gut.” They help people digest food and absorb some vitamins.
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Bacteria are used in bio-engineering. Some bacteria can make medicines. Some are
used to improve crops and farm animals.
12. Describe how bacteria can be harmful.
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Some cause disease: tuberculosis, pneumonia, bubonic plague, lyme disease
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Bacteria can infect cuts and wounds. Tetanus can be fatal.
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Bacteria cause tooth decay.
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Bacteria spoils food. A person could contract salmonella by eating spoiled food.
This could be fatal.
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Some bacteria harm crops and farm animals.
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Blue green bacteria can take over a pond and destroy the life that lives there.