TITLE OF LESSON PLAN:
Bacteria

LENGTH OF LESSON:
Two class periods

GRADE LEVEL:
9-12

SUBJECT AREA:
Microscopic World

CREDIT:
Lisa Lyle Wu, science teacher, Thomas Jefferson High School for Science and Technology, Alexandria, Virginia.

OBJECTIVES:
Students will understand the following:

1. Reproduction in bacteria may occur asexually by a form of cell division called fissionor sexually by a transfer of genetic material from a donor bacterium to a recipient.

2. Bacterial reproduction occurs in a number of stages.

3. Bacterial reproduction differs from mitotic reproduction in a single human cell.

MATERIALS:
For this lesson, you will need:

Research materials on bacteria and bacterial reproduction

Computer with Internet access

Clay for constructing models

PROCEDURE:

1. Review with your students what they have learned about cell reproduction, concentrating on reproduction in bacteria.

2. Using print materials and the Internet, students should discover that reproduction in bacteria may occur asexually by a form of cell division called fissionor sexually by a transfer of genetic material from a donor bacterium to a recipient.

3. Instruct students to take careful notes and make diagrams as they do their research.

4. In class, encourage students to share their research findings.

5. Have each student construct a clay model of one of the bacterial reproduction processes he or she has learned about. Each model should be labeled and accompanied by a paragraph identifying and describing the process illustrated by the model.

6. More advanced students can extend the project by writing paragraphs comparing and contrasting reproduction in bacteria with mitotic reproduction in a single human cell.

ADAPTATIONS:

Rather than having students do their own research on reproduction in bacteria, explain the process to them, using simple terms and diagrams.

DISCUSSION QUESTIONS:

1. Discuss ways that life on Earth depends upon bacteria.

2. Compare bacteria to other single-celled organisms. How do they differ? How do they compare to viruses?

3. Discuss the beneficial uses of bacterial toxins in medicine.

4. Explain how bacteria change and adapt to new environments.

5. Discuss how the widespread use of antibiotics in society has contributed to problems in daycare centers and hospitals.

6. Explain the importance of genetic research in understanding microorganisms.

7. Discuss how, in your daily living, you can protect yourself and others from contamination by pathogenic microorganisms.

8. Discuss how microorganisms are economically important to humans. 

EVALUATION:

You can evaluate your students on their models and paragraphs using the following three-point rubric:
  
Three points:model accurately constructed and clearly labeled; paragraph accurate, complete, clearly written
  
Two points:model adequately constructed and labeled; paragraph accurate but incomplete and lacking in clarity
  
One point:model inadequate and insufficiently labeled; paragraph incomplete, lacking in clarity, and containing inaccuracies
  
You can ask your students to contribute to the assessment rubric by determining what a viewer should be able to learn from a model.

EXTENSION:

Bacteria in the News
Some interesting bacteria in the news are leprosy, Lyme disease, and Pfiesteria piscicida—the toxic organism responsible for killing fish along the Atlantic coast. Have students investigate these or choose another infectious disease of an animal or plant. Students' investigations should cover the following: history, symptoms, pathogen, treatment, epidemiology (disease control). Students should include as many media sources as possible.

Oil Spill Lunch
Bioremediation is a process by which certain bacteria are used to degrade hazardous substances in the environment. Invite students to research the process of bioremediation as it has been applied to the treatment of oil spills. How does this natural process work? What are the growth requirements for the bacteria used? What conditions limit their population growth? What problems may arise if these populations of bacteria increase in the environment? What guidelines has the Environmental Protection Agency established for this practice? Have students present their case studies to the class.

SUGGESTED READINGS:

Virus X: Tracking the New Killer Plagues out of the Present and into the Future
Frank Ryan, M.D. Little, Brown and Company, 1997.
Join the author as he describes today's dangerous outbreaks of Hantavirus, Ebola, Marburg, “mad cow,” and the flesh-eating diseases, and then go into research laboratories and hospitals to see scientists and doctors who are trying to understand and contain these catastrophic epidemics.

Man and Microbes: Disease and Plagues in History and Modern Times
Arno Karlen. Jeremy P. Tarcher/Putnam Book, 1995.
Modern life has altered the environment, changed the relationship between humans and microbes, and generated new diseases. The author uses case studies and stories of medical detection to show the causes of these diseases and how scientists and doctors are working together to conquer this global crisis.

WEB LINKS:

Do You Have What It Takes to Fight Germs?
Current medical information on fighting germs and the current antibacterial soap business.
http://www.mayohealth.org/mayo/9708/htm/antibact.htm

Bacteria
Excellent overview of a course on bacteria with clearly organized information.
http://ccwf.cc.utexas.edu/~bogler/ecology/bacteria.html

The Microbe Zoo
A digital learning center for microbial ecology that would appeal to all ages. 
http://commtechlab.msu.edu/sites/dlc-me/zoo/

Bugs in the News
Award winning site with well written articles and links in viruses and bacteria.
http://falcon.cc.ukans.edu/~jbrown/bugs.html

Cells Alive
State of the Art site on cells that covers all aspects of bacteria and viruses. Appealing to all ages.
http://www.cellsalive.com/

VOCABULARY:

mutate
To change either the physical relation of chromosomes or the genetic sequence in an organism.
Context:
Bacteria do what they do best—mutate—changing to adapt to new conditions in their environment.

microorganism
An organism of microscopic or ultramicroscopic size.
Context:
We are destined to always live with microorganisms—from the friendly bacteria that help us digest food to the undesirable pathogens that make us sick.

pathogen
A specific causative agent of disease like a bacterium or virus.
Context:
Pathogens, such as salmonella and streptococcus, cause untold human misery.

plasmid
An extrachromosomal ring of bacterial DNA that replicates autonomously.
Context:
Plasmids hold genetic information.

enzyme
Any of numerous complex proteins that are produced by living cells and catalyze specific biochemical reactions at body temperatures.
Context:
In order for a microbe to consume food from its environment, it has to make enzymes, which break down the food into usable molecules.

culture medium
A nutrient system for the artificial cultivation of cells or organisms, especially bacteria.
Context:
There are many bacteria that can't be grown on culture media. 

microbiology
A branch of biology dealing especially with microscopic forms of life.
Context:
With the emergence of new technologies and new understanding about the functions of microorganisms, experts say this is the beginning age of microbiology.

ACADEMIC STANDARDS:

Grade Level:
6-8
Subject Area:
technology

Standard:
Understands the relationships among science, technology, society, and the individual.

Benchmarks:
Knows ways in which technology has influenced the course of history (e.g., revolutions in agriculture, manufacturing, sanitation, medicine, warfare, transportation, information processing, communication).

Grade Level:
6-8
Subject Area:
geography

Standard:
Understands the characteristics of ecosystems on Earth's surface.

Benchmarks:
Knows the effects of biological magnification in ecosystems (e.g., the increase in contaminants in succeeding levels of the food chain and the consequences for different life forms).

Grade Level:
6-8
Subject Area:
life science

Standard:
Understands how species depend on one another and on the environment for survival.

Benchmarks:
Knows ways in which species interact and depend on one another in an ecosystem (e.g., producer/consumer, predator/prey, parasite/host, relationships that are mutually beneficial or competitive).

Grade Level:
6-8
Subject Area:
life science

Standard:
Understands the genetic basis for the transfer of biological characteristics from one generation to the next.

Benchmarks:
Knows that hereditary information is contained in genes (located in the chromosomes of each cell), each of which carries a single unit of information; an inherited trait of an individual can be determined by either one or many genes, and a single gene can influence more than one trait.

Grade Level:
6-8
Subject Area:
life science

Standard:
Knows the general structure and function of cells in organisms.

Benchmarks:
Knows that disease in organisms can be caused by intrinsic failures of the system or infection by other organisms.

Grade Level:
9-12
Subject Area:
life science

Standard:
Knows about the diversity and unity that characterize life.

Benchmarks:
Knows how variation of organisms within a species increases the chance of survival of the species, and how the great diversity of species on Earth increases the chance of survival of life in the event of major global changes.

Grade Level:
9-12
Subject Area:
life science

Standard:
Understands the genetic basis for the transfer of biological characteristics from one generation to the next.

Benchmarks:
Knows ways in which genes (segments of DNA molecules) may be altered and combined to create genetic variation within a species (e.g., recombination of genetic material; mutations; errors in copying genetic material during cell division).

Grade Level:
9-12
Subject Area:
life science

Standard:
Knows the general structure and function of cells in organisms.

Benchmarks:
Understands the chemical reactions involved in cell functions (e.g., food molecules taken into cells are broken down to provide the chemical constituents needed to synthesize other molecules; enzymes facilitate the breakdown and synthesis of molecules).

Grade Level:
9-12
Subject Area:
life science

Standard:
Understands the basic concept of evolution of the species.

Benchmarks:
Knows that natural selection leads to organisms that are well suited for survival in particular environments, so that when an environment changes, some inherited characteristics become more or less advantageous or neutral, and chance alone can result in characteristics having no survival or reproductive value.

Grade Level:
9-12
Subject Area:
technology

Standard:
Understands the interactions of science, technology, and society.

Benchmarks:
Knows that technological knowledge is often not made public because of patents and the financial potential of the idea or invention; scientific knowledge is made public through presentations at professional meetings and publications in scientific journals.

DiscoverySchool.com
http://www.discoveryschool.com

Copyright 2001 Discovery.com.
Teachers may reproduce copies of these materials for classroom use only.