Reproduction in bacteria may occur asexually by a form of cell division called fission or 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.
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 fission or 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.
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.
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.
Definition: 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.
Definition: 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.
Definition: A specific causative agent of disease like a bacterium or virus. Context: Pathogens, such as salmonella and streptococcus, cause untold human misery.
Definition: 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.
Definition: 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.
Definition: 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.
This lesson plan may be used to address the academic standards listed below. These standards are drawn from Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education: 2nd Edition and have been provided courtesy of the Mid-continent Research for Education and Learning in Aurora, Colorado.
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.
