INTRODUCTION TO MICROBES
WHAT IS A MICROORGANISM?
tiny
living thing
A microorganism or microbe is a tiny living thing that we cannot see without the aid of a microscope.
There can be millions or even billions of microorganisms in one place. Some are helpful and some
are harmful. Because they are mostly living things, they grow, move, reproduce, eat, give off waste,
are sensitive to their environments, and have cells. The study of microorganisms is called microbiology.
Because microorganisms are living things, they have the same requirements that
all living things have. They need:
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Oxygen
Food Flesh-Eating Bacteria
Good temperature Extreme Temperatures
Reproduction Bacterial Reproduction
Waste disposal Paramecium Waste Disposal
Water Microorganisms in a Water Drop
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MICROORGANISMS’ REQUIREMENTS FOR LIVING
TYPES OF MICROBES
1. Viruses
2. Bacteria
3. Fungi
4. Protists
4 Types of Microbes
Microbes can be helpful and harmful. They are found almost everywhere, even inside
and outside of our bodies. They can cause serious diseases. Microbes even clean our
water and digest our food. Most must be viewed under a microscope.
4 TYPES OF MICROBES
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Only exist to reproduce and make you sick!! (They cannot reproduce independently.)
Can’t stay alive unless they invade another plant, animal, or bacterial cell
Can invade almost anything
Can’t move on their own
The smallest and simplest of all microbes
They hijack other cells, inject genetic codes, and force them to create new viruses
How a Virus Invades Your Body
Causes disease like polio, chicken pox, measles
They are NOT living things but are microscopic
Antibiotics can’s kill viruses only bacteria
What is a Virus?
VIRUSES
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First to appear on earth
Mostly good and helpful
Single-celled
Used to make yogurt, cheese, chocolate, raw meats, coffee, food preserved with vinegar
Lives in almost every material and environment
Over 4,000 species are known
Causes disease like typhoid fever, salmonella, cholera, staph infection, and E-coli
Involved in fermentation
Can make their own food, live off dead materials, or absorb materials from other living
organisms (including humans!)
Antibiotics kill bacteria
Comes in many shapes, including rod-shaped, spherical-shaped, and spiral-shaped
Bacteria for Kids
BACTERIA
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Eats almost anything (including manure) and LOVES dead plants and animals
They are considered decomposers because they break things down – Earth’s clean-up crew
Lives by absorbing nutrients from dead or decaying things
100,000 species
Fungus (singular) or fungi (plural)
In foods like moldy cheese, soy sauce, mushrooms, breads
Most well known are yeast, mushrooms, mold, and mildew
Forms in clusters of cells
Yeast is a fungus
Reproduce by sending out spores Spores in Action Video
They produce medicine (penicillin)
They cause diseases like athlete’s foot and ringworm
FUNGUS
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Two main categories: 1) algae – make their own food (producers) OR
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protozoans search for food (consumers) Amoeba Eating Paramecium
Some major groups: amoeba, diatoms, euglena, algae, protozoa, slime & water molds (not
fungus) Protists Video
200,000 species
Parasitic protists that live on people or animals are called pathogens
They act fungus-like (slime mold), animal-like (protozoans), or plant-like (algae)
Live mostly in water and is the cause of the disease giardia
Single-celled and multicellular but different shapes and sizes
Can have appendages such as cilia (hairs), flagellum (tail) or flagella (tails), or pseudopods
(false feet) surrounding it
Found in foods like ice cream, sour cream, sushi, and products like fertilizer and toothpaste
Plant-like protists make its own food (chlorophyll) by photosynthesis Protists Song
PROTISTS
REVIEW
With a partner or as a class, discuss what the four types of microbes are as
well as characteristics of each.
Review these words:
Decomposer
Flagellum
Unicellular
Decay
Multicellular
Yeast
Cilia
Microbiology
Pseudopod
Organism