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TEACHER’S GUIDE
Follow-up Activities
• Imagine a colony of 10 bacteria that doubles every 20 minutes. Have
students calculate how many bacteria will be in the colony after two
hours. Based on this information, have each student guess how long it
would take for the colony to surpass one million organisms.Then ask the
students to do the computation and compare their guesses with the
calculated time.
• Have students conduct a poll to determine if people consider bacteria
helpful or harmful. Tally the results and make graphs for the subgroups
polled such as: elementary students, teens, high school students,
parents and grandparents.
• Have students observe the effect of temperature on a glass of milk at
room temperature over the course of a few days and compare it to a
glass of milk that has been refrigerated. Students can then design an
experiment that proves that refrigeration is useful in retarding bacteria
growth.
• Explain to students that people have not always known that bacterial
infections can be prevented by hand-washing. Refer students to the Web
page www.accessexcellence.org/AE/AEC/CC/hand_background.html
for information about the history of hygiene in public health and for lab
activities designed to illustrate the fact that bacteria are present virtually
everywhere.
TEACHER’S GUIDE
TEACHER’S GUIDE
Suggested Print Resources
• Gottfried,Ted. Alexander Fleming: Discoverer of Penicillin. Franklin
Watts, Danbury, CT; 1997.
• Holley, Dennis. Viruses and Bacteria: Hands-On Minds-On
Investigations for Middle to High School Students. Critical Thinking
Books and Software, Pacific Grove, CA; 1999.
• Levine, Shar. Fun With Your Microscope. Sterling Publishers, New York,
NY; 1999.
• Lovett, Sarah. Micro Monsters. Davidson Title, Jackson,TN; 1996.
Bacteria
Grades 5–8
S
tudents in grade 5–8 classrooms possess a wide range of
background knowledge. Student response to this video
program is sure to be varied, so the teachers at these grades
need all the help they can get! This guide has been designed
to help the 5–8 science teacher by providing a brief synopsis of the program, previewing and follow-up questions,
activities, vocabulary and additional resources.
Before Viewing: Extensive research tells how important
it is for the teacher to discover what the students know —
or think they know — about a topic, before actually starting a new unit.Therefore, after prompting discussion with
the pre-viewing questions, lead your class to create an
“Everything We Think We Know About…” list.You may also
wish to preview key vocabulary words, and have students
raise additional questions they hope will be answered.
Suggested Internet Resources
Periodically, Internet Resources are updated on our Web site at
www.LibraryVideo.com
• www.amnh.org/explore/infection/index.html
“Infection Detection Protection” is a Web site hosted by the American
Museum of Natural History that contains a great deal of information
about microbes and their effect on our lives. Several interactive games
that teach about bacteria are also included.
• www.microbe.org/microbes/bacterium1.asp
The American Society for Microbiology hosts “Stalking the Mysterious
Microbe,” a site for elementary students interested in learning more
about microorganisms including bacteria.
• commtechlab.msu.edu/sites/dlc-me/zoo/
The “Microbe Zoo” is an excellent interactive site for middle-schoolers,
developed with the input of scientists from Michigan State University.
Teacher resources and activities about bacteria are included.
• www.fightbac.org/educators/gameplan.htm
Hands-on activities for middle school students concerning the fight
against bacteria are available on this site and are sponsored by the
Partnership for Food Safety Education.
5
TEACHER’S GUIDE CONSULTANT
Conrad M. Follmer
25 years as a K–5 Science & Math Coordinator for a Pennsylvania public
school system, currently an independent consultant to elementary schools.
After Viewing: Have your students share video excerpts
that fascinated or surprised them, then challenge your students to prove or disprove the accuracy of the facts they
put on their “Everything We Think We Know About…” list.
Discuss what else they learned and use the follow-up questions and activities to inspire further discussion. Encourage
students to research the topic further with the Internet and
reading resources provided.
TITLES
• BACTERIA
• FUNGI
Teacher’s Guides Included
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Program Summary
nucleus — A membrane-bound structure within a cell that contains the
Pre-viewing Discussion
Before students generate their list of “Everything We Think We Know
About...” for this topic, stimulate and focus their thinking by raising these
questions so that their list will better reflect the key ideas in this show:
• What was the first life form on Earth?
• Where are bacteria found?
• How do bacteria affect other organisms?
After the class has completed their “Everything We Think We Know
About...” list, ask them what other questions they have that they hope will
be answered during this program. Have students listen closely to learn if
everything on their class list is accurate and to hear if any of their own
questions are answered.
The following words are included for teacher reference or for use with students. They are listed in the order in which they appear in the video.
bacteria (singular: bacterium) — Simple, single-celled microorganisms
with a cell wall, but no cell structures.The most numerous and ancient of all
creatures, they contain only cytoplasm and floating genetic information.
Kingdom Monera — The scientific category that includes all simple organisms without a nucleus.
(Continued)
genetic information that the cell needs to grow and divide. Bacterium cells do
not have a defined nucleus; their genetic material floats within the cell.
microoganism — A small living thing that cannot be seen without a microscope.
microbe — A microscopic organism like a bacterium.
spirilla (singular: spirillum) — Bacteria that are twisted in shape,
looking like a spiral staircase.
bacillus (plural: bacilli) — A straight, rod-shaped bacterium.
coccus (plural: cocci) — A spherical bacterium.
Alexander Fleming — (1881–1955 CE) The Scottish physician who
observed in 1928 that a substance produced by a fungus could kill bacteria.
This was the first antibiotic, which he named penicillin.
penicillin — An antibiotic made by the mold species Penicillium notatum.
antibiotic — A drug that interferes with the growth of bacteria. Penicillin,
made by mold, was the first antibiotic.
archaebacteria — (Greek – “archae”: “ancient”) Microorganisms found in harsh
environments lacking oxygen and believed to be among the first to live on Earth.
anaerobic — A word that describes organisms that can survive only in
places where there is no oxygen.
aerobic — A word used to describe organisms that need oxygen to survive.
photosynthesis — The process through which sunlight is trapped and
chemically combined with water and carbon dioxide to produce sugars and
oxygen.
cell wall — The protective, rigid outer layer of the cells of plants, fungi and
bacteria.
cytoplasm — The jellylike substance that makes up the majority of a living
cell. In bacteria, the genetic information floats in the cytoplasm and is not
contained in a nucleus.
endospore — A stage in the life cycle of some bacteria that can occur when
living conditions are not supportive. Bacteria can lie dormant for prolonged
periods as endospores, withstanding boiling and freezing.
asexual reproduction — The creation of new organisms without the
union of two individuals.Asexual reproduction can involve budding, spore formation and fission.
binary fission — A method of asexual reproduction in which an individual
cell replicates its genetic information, then splits itself into two identical cells.
In bacteria, this doubling can happen every 20 minutes.
conjugation — A method of reproduction in which one organism transfers
hereditary material to another, creating a genetically different cell.
flagella — Little whip-like structures that help some bacteria to move around.
autotrophs — Organisms that make their own food.
heterotrophs — Organisms that get their food from an outside source.
decomposers — Organisms that are responsible for breaking down organic
matter, decomposing it into simpler form and recycling their nutrients into
the soil.
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Humans share the Earth with countless numbers of microscopic organisms.
The most simple and numerous of all these organisms are the members of the
scientific kingdom Monera, commonly known as bacteria. Bacteria thrive
everywhere on the planet — in soil, water and air — even inside other creatures! In fact, we have billions of harmless bacteria growing in our mouths
alone. Bacteria are the most ancient creatures on Earth and are responsible for
creating the Earth’s breathable atmosphere billions of years ago. Though
single-celled bacteria are the simplest of living creatures, with no true
nucleus, they are essential for life.
Three and a half billion years ago, Earth’s first living organisms, called archaebacteria, thrived in an atmosphere with no oxygen. Over time, some bacteria
began making food through photosynthesis and releasing oxygen as a
byproduct. Over billions of years, these bacteria created Earth’s breathable
atmosphere, making life as we know it possible. Some bacteria, called anaerobes, cannot survive in our oxygen-rich atmosphere.These relatives of the
archaebacteria can be found in the intestines of animals, deep in compost
piles, in sewers and even around undersea volcanic vents.Aerobic bacteria are
everywhere else!
While most types of bacteria are helpful, there are harmful species that may
cause disease. During World War I, Scottish physician Alexander Fleming discovered the first antibiotic — a substance that kills bacteria. Fleming observed
that something produced by the fungus Penicillium notatum was interfering
with the growth of the harmful bacteria that he was studying. He named this
substance penicillin and before long, this drug was responsible for saving
many millions of lives from bacterial infections.
Many bacteria are successful because they are able to wrap themselves in a
protective coating called an endospore whenever living conditions become
inhospitable.They can stay dormant until conditions improve, even in boiling
and freezing environments.Another reason for their success is their ability to
reproduce so rapidly. Bacteria reproduce asexually; each bacterium replicates
its genetic information, swells up and splits, creating two identical cells. Under
ideal conditions, some bacteria can double their numbers every 20 minutes!
All living things have a partnership with bacteria.The Earth itself depends
upon bacteria as a major agent in decomposition.These decomposers break
down dead plants and animals, recycling their nutrients into the soil for future
use.Animals depend upon bacteria to break down the foods they eat, helping
in the digestion process. We also use cultures of bacteria to make certain
foods, such as cheese and yogurt. So even though some bacteria cause diseases, they are simply organisms that we simply can’t live without!
Vocabulary
Focus Questions
1. Is the purpose of bacteria to make us sick? Explain.
2. Describe three basic shapes of bacteria.
3.Where can bacteria be found?
4. Name some effects of the bacteria staphylococcus.
5.Who was Alexander Fleming? Describe his discovery.
6.What are archaebacteria, and what was their contribution to life on
Earth?
7.What is the difference between aerobic and anerobic organisms?
8. Describe the basic structure of a bacterium.
9.What is binary fission? Why is this method of reproduction so effective
for bacteria?
10. Explain the difference between autotrophs and heterotrophs.
11.Why are bacteria considered to be decomposers? Explain.
12.What are the key conditions for bacteria growth?
Follow-up Discussion
Research indicates that students will retain their previous misconceptions
about a topic, in preference to new information, until they actively recognize and correct their own errors. Therefore, it is important to have your
students re-examine the facts/beliefs they put on their “Everything We
Think We Know About...” list. It might also be helpful to review the list by
marking each entry with a “+” or “-” to show which facts were correct and
which were incorrect.
Thought provoking discussions provide a good way to assess the overall
depth of student understanding. The following are some suggested discussion topics.
• Discuss the value of bacteria.Are bacteria helpful or harmful to Earth’s
inhabitants? Explain your reasoning.
• Discuss in what locations bacteria are most likely to be found.Why do
you think so?