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SBI3C�Microbiology

Introduction to the Microbial World

Adapted from:

BioEd Online

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Microbiology and Microorganisms

Microbiology is the study of microscopic organisms that are either unicellular (single cell), or multicellular (many cells).
The term microbe is short for microorganism, which means “small organism”
Microbes are the oldest form of life on Earth. Some types have existed for billions of years

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True or False

The existence of microscopic organisms was discovered during the late 1600’s
All bacteria are harmful
The human body has more microbes than there are human cells
Bread rises due to gases produced by a fungus
Viruses are living
One cubic inch of soil can contain enough of the fungal species called mycelia to stretch 8 miles.

T

F

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K-W-L Chart

What I Know	What I Want to Know	What I Learned

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Five Major Groups of Microbes

Bacteria (such as E. coli, above)

Fungi –molds, mushrooms, yeasts (C. cassiicola fungus, above)

Protists – Protozoa, algae, water and slime molds

Viruses (such as Ebola, above)

Archaea or “Archaebacteria” (such as Marsarchaeota found in iron oxide mats surrounding springs in Yellowstone Park)

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From The Science of Microbes Teacher’s Guide: “The Variety and Roles of Microbes”

C. cassiicola causes “leaf spotting disease” in soybeans, cucumbers, tomatoes and tobacco. Other plants also are sometimes affected.

The Science of HIV/AIDS: The Virus, the Epidemic and the World © Baylor College of Medicine (ISBN: 978-1-888997-62-0), was developed with support from a Science Education Partnership, National Institutes of Health (NIH), grant number 5R25 RR018605, and in partnership with the Baylor-UT Houston Center for AIDS Research, an NIH-funded program, AI036211.

Photo of Escherichia coli bacteria courtesy of the CDC\9995\E. White, P. Hayes. http://phil.cdc.gov/phil/

Photo of Corynespora cassiicola fungus courtesy of the CDC\4203\L. Aiello. http://phil.cdc.gov/phil/

Photo of Flagellate protist courtesy of Ron Neumeyer © MicroImaging Services. http://www.microimaging.ca/protozoa/index.html

TEM of Ebola virus courtesy of the CDC\1832\C. Goldsmith. http://phil.cdc.gov/phil/

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What about viruses?��Are they living?

Refer to pg. 99 in your textbook

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Viruses – Living or Not?

- Viruses do have nucleic acids but reproduce only inside a host organism

- Do not have cells

- Cannot make proteins themselves

- Cannot use energy

Without a host, a virus is simply a group of chemicals.

So, viruses are not considered living organisms and do not get a taxonomic classification.

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Observing Different Microbes

A light microscope image reveals the inner structure

A very good compound light microscope can magnify objects as much as 2,000 times (2000x).

Baker’s Yeast

Paramecium

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Special Microscopes

A transmission electron microscope (TEM) uses an electron beam that passes through a specimen, enabling the interior of an object to be observed (see image above right)

Mag. >50 million X

A scanning electron microscope (SEM) uses electrons to image the surface of an object (see image below right).

Mag. = 1-2 million X

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Microbe Size comparison: https://www.youtube.com/watch?v=h0xTKxbIElU

From The Science of Microbes Teacher’s Guide: “Tools of Magnification”

Legionella pneumophila bacterium causes Legionnaire’s disease.

The Science of HIV/AIDS: The Virus, the Epidemic and the World © Baylor College of Medicine (ISBN: 978-1-888997-62-0), was developed with support from a Science Education Partnership, National Institutes of Health (NIH), grant number 5R25 RR018605, and in partnership with the Baylor-UT Houston Center for AIDS Research, an NIH-funded program, AI036211.

TEM (upper right) of Legionella pneumophila bacterium courtesy of the CDC\7306. http://phil.cdc.gov/phil/details.asp?pid=7306

SEM of Legionella pneumophila courtesy of the CDC\6640\B. Fields. http://phil.cdc.gov/phil/home.asp

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Where do microbes live?

Soil
Water
Toxic waste dumps
Jet Fuel
Kitchen counters
Your intestines
Boiling hot springs

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Microbes in Extreme Environments

Some microbes grow both at or above pH 8 and at or above 60°C. �

The Three Buddhas geysers in the Nevada Hot Springs is one place where heat-tolerant microbes within the domain Archaea can be found.

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Microbes and Diseases

Most microbes are not harmful.
Only around 5% can cause disease.

Mycobacterium tuberculosis (causes TB)

influenza virus particles

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Microorganism Sorting Activity

Match the pictures (1 or 2) and descriptions (3 each) to the correct microorganism (e.g. Bacteria, viruses etc.)

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Bacterium

?

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