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BIO307: Microbiology

Unit 1: Microbes   Microbes are microscopic; thus, we cannot see them by the naked eye. Antoni van Leeuwenhoek crafted the first microscope lenses that magnified over 200 times, and he turned his lenses towards everything. He saw blood cells, sperm, hatching ants, and every cellular microbe groups that we know of today. About 150 years later, Louis Pasteur’s meticulously designed swan-necked flask experiments were instrumental in putting off the spontaneous generation hypothesis for microbes. Pasteur showed that microbes arise from microbes, and they are not generated spontaneously from non-living matter. Before any microbe has ever been linked to a disease, the independent death rate analyses of Semmelweis and Nightingale led to the introduction of procedures that we call antiseptic today. Koch was the first to photograph a pathogen in infected tissue; he also laid down guidelines on how to link a microorganism to a disease. These guidelines are Koch’s postulates. Only a few microbes cause disease; most microbes are harmless. Microbes are present in all three domains of life: Bacteria, Archaea, and Eukaryota.

Unit 1 Time Advisory
Completing this unit should take you approximately 15 hours.

☐    Subunit 1.1: 4.25 hours

 

☐    Subunit 1.1.1: 2.5 hours

☐    Subunit 1.1.2: 1.75 hours

☐    Subunit 1.2: 2 hours

☐    Subunit 1.3: 0.5 hours

☐    Subunit 1.4: 1.25 hours

☐    Subunit 1.5: 1 hour

☐    Subunit 1.6: 6 hours

 

☐    Subunit 1.6.1: 1.5 hours

☐    Subunit 1.6.2: 0.75 hours

☐    Subunit 1.6.3: 1.25 hours

☐    Subunit 1.6.4: 2 hours

☐    Subunit 1.6.5: 0.5 hours

 

☐    Subunit 1.7: 0.75 hours

Unit1 Learning Outcomes
Upon successful completion of this unit, you will be able to: - explain what microbes are; - recognize and distinguish micrographs taken by light, phase contrast, and electron microscopes; - predict microbial growth in experiments similar to Pasteur’s experiment; - employ Koch’s postulates for the identification of a pathogen; identify the limits of Koch’s postulates in the real world; - design ways to control microbial growth; - compare and contrast microbes of the three domains of life; and - compare and contrast cells and viruses.

1.1 Microscopic Life   1.1.1 Magnification Is the Key: Leeuwenhoek Discovers Animalcules   - Web Media: Dr. Brian J. Ford's “History of the Microscope” Link: Dr. Brian J. Ford’s “History of the Microscope” (HTML)
 
Instructions: Read this webpage. At the end of the webpage, click on “Extract from a major lecture” to move to the next page. At the top of the new webpage, click on “Multimedia demonstrations” to access two video presentations: “1. Extract of Linnean Society talk” and “2. Leeuwenhoek studies sperm.” You may want to watch these videos a couple of times. Next, move back to the previous page where you clicked on “Multimedia demonstrations,” and click on “Leeuwenhoek as experimental biologist.” Read the article, “From Dilettante to Diligent Experimenter: a Reappraisal of Leewenhoek as Microscopist and Investigator.” Please note that Leeuwenhoek crafted superior lenses, which allowed him to observe live microbes, and he also well-documented his observations.
 
Reading these webpages should take approximately 2 hours. 
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Reading: Microbe.org: Jeffrey Noel’s “Microbe Types” Link: Microbe.org: Jeffrey Noel’s “Microbe Types” (HTML)
     
    Instructions: Read this webpage. Please note that Leeuwenhoek described representatives of all cellular microbes, including prokaryotes, protists, and fungi. The magnification and resolution of Leeuwenhoek’s lenses were not sufficient to describe infectious non-living particles, such viruses, viroids, and prions.
     
    Reading this webpage should take approximately 30 minutes. 
     
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1.1.2 The Modern Microscopes   - Assessment: Nobelprize.org’s “Microscope Quiz” Link: Nobelprize.org’s “Microscope Quiz” (Flash)
 
Instructions: Complete this quiz. There are 20 multiple choice questions, and you will receive immediate feedback after you select a response. You should strive to pass with at least 90% accuracy before moving on. If your result is lower than 90%, then return to the Nobelprize.org’s “Microscope” reading, study it thoroughly, and then re-take the quiz.
 
Taking this quiz should take approximately 15 minutes.
 
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  • Reading: Nobelprize.org’s “Microscopes” Link: Nobelprize.org’s “Microscopes” (HTML)
     
    Instructions: Read the “Microscopes – Help Scientists Explore Hidden Worlds” section. Then, click on the links “From Thrilling Toy to Important Tool,” “Microscopy Time Line,” and “Resolving Power Line,” and read these pages as well. You can always return to the starter page by hitting the “Back” button on the top right corner of the window. From the main page, click on the links “Phase Contrast Microscopes,” “Fluorescence Microscopes,” “Transmission Electron Microscopes,” and “Scanning Tunneling Microscopes,” and study these pages to learn about modern microscope techniques. 
     
    Reading these webpages should take approximately 1 hour and 30 minutes.
     
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1.2 Spontaneous Generation vs. Biogenesis   - Reading: The Microbial World: Through the Microscope: “1-9 Spontaneous generation was an attractive theory to many people, but was ultimately disproven.” Link: The Microbial World: Through the Microscope: “1-9 Spontaneous generation was an attractive theory to many people, but was ultimately disproven” (HTML)
 
Instructions: Read this webpage. The origin of life has always been fascinating, and the discovery of microbes was also followed by a debate on their origins. Prominent scientists of the time performed experiments to prove or disprove the spontaneous generation of microbes from non-living matter. The debate was going on for about 200 years, when finally Pasteur put off the spontaneous generation theory with a set of smartly designed and carefully performed experiments.      
 
Reading this webpage should take approximately 1 hour.
 
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  • Reading: The National Health Museum Resource Center: Access Excellence: Seung Yon Rhee’s “Louis Pasteur (1822-1895)” Link: The National Health Museum Resource Center: Access Excellence: Seung Yon Rhee’s “Louis Pasteur (1822-1895)” (HTML)
     
    Instructions: Read this webpage. Louis Pasteur was a meticulous experimenter, who believed that hard work should bring results. As Pasteur stated, “Chance favors only the prepared mind.”
     
    Reading this webpage should take approximately 30 minutes.
     
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  • Activity: W. H. Freeman’s “Pasteur’s Experiment” Link: W. H. Freeman’s “Pasteur’s Experiment” (Flash)
     
    Instructions: Read the “Introduction” as a review on Pasteur’s experimental design for testing spontaneous generation. Next, click on the “Animation” tab, choose “Step-through” or “Narrated,” and follow the instructions. You will be prompted to answer questions during the animation. Read the conclusion after completing the animation. Finally, complete the quiz.
     
    Reading this resource and taking the quiz should take approximately 15 minutes.
     
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1.3 The Germ Theory   - Reading: Harvard University Library’s Contagion: “Robert Koch, 1843 – 1910” Link: Harvard University Library’s Contagion: “Robert Koch, 1843 – 1910” (HTML)
 
Instruction: Read this webpage. Note the significance and limits of Koch’s postulates in the identification of the causative agent. Koch took the first photomicrograph of bacteria and the first photomicrograph of bacteria in diseased tissue.
 
Reading this webpage should take approximately 30 minutes.
 
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1.4 Antiseptic Procedures   - Reading: The Encyclopedia Britannica: Zoltán Imre’s “Ignaz Philipp Semmelweis” Link: The Encyclopedia Britannica: Zoltán Imre’s “Ignaz Philipp Semmelweis” (HTML)
 
Instructions: Read this webpage. Today, native Hungarians regard Semmelweis as “the savior of mothers”; however, during his life, many rejected his chlorine hand-wash antiseptic procedure. The childbed fever death rates dropped from 18% to 2% when he was in charge in the clinics and increased 10-fold when he was removed. The web media below connects you to a graph that was generated based on Semmelweis’ data on childbed fever mortality. The Semmelweis’ reflex term is used to describe the irrational rejection of the very obvious. 
 
Reading this webpage should take approximately 30 minutes.
 
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  • Web Media: Wikipedia’s “Yearly Mortality Rates” Link: Wikipedia’s “Yearly Mortality Rates” (PNG)
     
    Instructions: Study this graph, which was generated from the data published by Semmelweis in 1861. Note that in the Wien maternity clinic, pathological anatomy was permitted; thus, physicians and medical students could carry pathogens from cadavers to patients. The Dublin maternity hospital had no medical pathology. Note the death rate drop after the introduction of the chlorine handwash. Wikimedia Commons user Power.corrupts constructed this graph using Semmelweis’s data.

    Studying this graph should take approximately 5 minutes.
     
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  • Reading: University of Houston: John Lienhard’s “Nightingale’s Graph” Link: University of Houston: John Lienhard’s “Nightingale’s Graph” (HTML)
     
    Instructions: Read this webpage. Note that Nightingale generated the polar-area diagram; she was very successful in communicating her findings with these graphs.
     
    Reading this webpage should take approximately 30 minutes.
     
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1.5 General Antimicrobial Methods   - Reading: Dr. Kenneth Todar’s Online Textbook of Bacteriology: “Control of Microbial Growth” Link: Dr. Kenneth Todar’s Online Textbook of Bacteriology: “Control of Microbial Growth” (HTML)
 
Instructions: Read this chapter to review the methods and techniques used to control the growth of microorganisms. Make sure to click on the “Chapter Continued” link at the bottom of each webpage to read all 6 pages of the chapter.
 
Reading this chapter should take approximately 1 hour.
 
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1.6 Classification System   1.6.1 Three Domains of Life   - Reading: University of California: Ben Waggoner & B.R. Speer’s “UCMP Phylogeny Wing: The Phylogeny of Life” Link: University of California: Ben Waggoner & B.R. Speer’s “UCMP Phylogeny Wing: The Phylogeny of Life” (HTML)
 
Instructions: Read this webpage to review the three domains of life. You have learned about the classification system in BIO102: Introduction to Evolutionary Biology and Ecology. Microscopic forms of life can be found in all three domains.
 
Reading this webpage should take approximately 30 minutes.
 
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  • Reading: Scitable: Dr. Eugene V. Koonin’s “The Two Empires and the Three Domains of Life in the Postgenomic Age” Link: Scitable: Dr. Eugene V. Koonin’s “The Two Empires and the Three Domains of Life in the Postgenomic Age” (HTML)
     
    Instructions: Read this webpage. Note that genetic data indicate DNA transfer between species to some extent.
     
    Reading this webpage should take approximately 1 hour.
     
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1.6.2 Prokaryotes and Eukaryotes   - Reading: College of DuPage: Professor Lynn Fancher’s “Prokaryotic and Eukaryotic Cells” Link: College of DuPage: Professor Lynn Fancher’s “Prokaryotic and Eukaryotic Cells” (HTML)
 
Instructions: Read this webpage to review the prokaryotic and eukaryotic cell structure.
 
Reading this webpage should take approximately 30 minutes.
 
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  • Assessment: The Saylor Foundation’s “Eukaryotes and Prokaryotes” Link: The Saylor Foundation’s “Eukaryotes and Prokaryotes” (HTML)
     
    Instructions: Instructions: Complete this one question assessment. If your answer is correct, then it is acknowledged with a short explanation. Be sure to read each explanation carefully. If you click on a wrong answer, then you will go to a tutorial page. Read this page carefully and then return to the assessment and attempt to complete it again. 

    Remember that there are microbes among prokaryotes and eukaryotes as well.
     
    Completing this assessment should take approximately 15 minutes.
     
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1.6.3 Archaea   - Reading: University of California: Ben Waggoner & B.R. Speer’s “Introduction to Archaea” Link: University of California: Ben Waggoner & B.R. Speer’s “Introduction to Archaea” (HTML)
 
Instructions: Read this webpage. Note that archaea adapt to diverse environments. Many archaea are extremophile, meaning they live in an environment that seems very hostile to the human eye.
 
Reading this webpage should take approximately 15 minutes.
 
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  • Reading: University of California: Ben Waggoner & B.R. Speer’s “Archaea: Morphology” Link: University of California: Ben Waggoner & B.R. Speer’s “Archaea: Morphology” (HTML)
     
    Instructions: Read this webpage. Note the molecular differences between the bacterial and archaea cell membrane and cell wall.
     
    Reading this webpage should take approximately 30 minutes.
     
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  • Reading: John W. Kimball’s “Archaea” Link: John W. Kimball’s “Archaea” (HTML)
     
    Instructions: Read this webpage. Note that some archaea traits are similar to eukaryotes, while other traits are similar to prokaryotes.
     
    Reading this webpage should take approximately 30 minutes.
     
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1.6.4 Bacteria   - Reading: Dr. Kenneth Todar’s Online Textbook of Bacteriology: “Structure and Function of Bacterial Cells” Link: Dr. Kenneth Todar’s Online Textbook of Bacteriology: “Structure and Function of Bacterial Cells” (HTML)
 
Instructions: Read this chapter to learn about the structure and function of bacterial cells. Make sure to click on the “Chapter Continued” link at the bottom of each webpage to move on to subsequent pages. When you reach the last page of the chapter, you will see an “End of the Chapter” note. 
 
Reading this chapter should take approximately 2 hours.
 
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1.6.5 Eukaryotic Cell   - Web Media: Wisconsin College Technical System’s WISC-Online: Barbara Liang’s “Identifying Eukaryotic Animal Cell Organelles” Link: Wisconsin College Technical System’s WISC-Online: Barbara Liang’s “Identifying Eukaryotic Animal Cell Organelles” (Flash)
 
Instructions: Navigate your way through these slides on organelles by pressing “Next,” located at the bottom of the slide frame. There are a total of 13 slides. Note that there are eukaryotic microorganisms among fungi and protists.
 
Studying these slides should take approximately 30 minutes.
 
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1.7 Viruses   - Reading: Scitable: Dr. David R. Wessner’s “The Origins of Viruses” Link: Scitable: Dr. David R. Wessner’s “The Origins of Viruses” (HTML)
 
Instructions: Read this webpage. Note that the cell is the smallest unit of life, because it can support its own life including reproduction. Viruses cannot support their own life, but they can hijack the metabolism of specific host cells. Without a specific host cell, a virus cannot grow, change, develop, or multiply. 
 
Reading this webpage should take approximately 45 minutes.
 
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