7C45 World of Microbes

Kingdoms

• Scientists classify living organisms into 6 main groups called Kingdoms. These include:– Animals– Plants– Fungi– Protists– Bacteria– Archaea

Microbes

• Germ = microbe that causes disease.• Microbes cause most infectious diseases.• Microbes include Protists, Bacteria, Fungi, and

Viruses. Since viruses are not alive, they are not organisms. This is why we call them microbes and not microorganisms.

First 3 Kingdoms

• You are familiar with Animals and Plants.• The 3rd Kingdom is Fungi, and includes:– Mushrooms– Yeast– Mold

Protist• Protist is a single-celled microbe with a nucleus• Some cause illness but many are harmless.• Some Trypanosoma cause sleeping sickness.• Most Paramecium are harmless.• Some Amoeba cause digestive illness.

Bacteria/Archaea

• These are single-celled without a nucleus.• They are also the most common microbes and

are tiny (1000 could fit on the dot of an “i”).• Some cause diseases but some are helpful.• Without them nothing would decompose.• Some are important in food and drinks. Most

yogurt have “live and active yogurt cultures” made by fermentation of milk by bacteria.

Bacteria Types: Spheres

• Diplococci (pairs)– Pneumonia

• Staphylococci (cluster)– Skin infection

• Streptococci (chains)– Strep throat

Bacteria Types: Rods

• Bacilli (rods)– Upset stomach

• Mycobacteria (chains)– Tuberculosis

Bacteria Types: Others

• Vibrio (curved rod)– Cholera

• Spirilla (short spiral)– Decomposers

• Spirochete (long spiral)– Syphilis

• Actinomyces (branched chain)– Produce antibiotics

Virus Discovery• Virus was discovered in 1898, about 45 years

before they were seen. Diseased tobacco plants had no bacteria even though the disease was infectious. It was thought that the disease was caused by a tiny unseen microbe they called “virus” which means “poison” in Latin.

• Seen with electron microscopes in 1939, we now know they cause flu, colds, chickenpox, and AIDS.

Virus

• Microbe, with no cells.• Smallest, but not a living organism.• They have genetic material, but not in a nucleus.• They cannot grow or reproduce independently or

carry out life functions like respiration.• Instead they rely on cells of living organisms for

their reproduction.• They are non-living germs that cause disease so

we call them microbes not microorganisms.

Average Microbe Sizes

1. Virus .

2. Bacterium

3. Protist

Compare Protist and BacteriaPages C71-72

Protist1. Microbe

2. Draw/Color Protists

3. Compare Protists & Bacteria

Bacteria1. Microbe

2. Draw/Color Bacteria

Compare Protist and Bacteria

Protist• Microbe• Largest• One cell• Living organism• Cell membrane• Genetic material• Nucleus• Cytoplasm• Organelles

Bacteria• Microbe• Smaller• One cell• Living organism• Cell wall• Cell membrane• Genetic material• No nucleus• Cytoplasm• Organelles

Compare/Contrast Microbes:Draw and Complete this Venn Diagram

Protist B Bacteria

Virus

Protist Bacteria

living organisms, nucleus, cell membrane, cell wall,organelles, cytoplasm, 1 cell smaller largest

genetic material, genetic microbes material not

in nucleus

not living, not a cell, smallest

Virus

C45 Microbe World Analysis(answer using 1 paragraph each)

1. Can a microbe NOT be helpful OR harmful?2. If you look through a microscope and see a

long organism with a round structure inside of it, is it a protist, bacterium, or virus?

3. What are some advantages of using highest microscope power? Low power advantages?

4. Why are viruses NOT microorganisms?