BIOTECH                                                                                                 ROOM COPY
                    WORKSHEET: INTRODUCTION TO MICROBIOLOGY

1. What was the basis of peoples’ belief in:
     a) abiogenesis                                                       b) biogenesis

2. What are each of the following scientists famous for?
     a) Helmont                                                             b) Pasteur

3. a) What is type of food is often fermented?
    b) What general type of food is usually pasteurized?
        (Critical Thinking)
    c) Why were fermented drinks, such as wine, safer to drink in medieval time?
    d) Why must milk be pasteurized before being sold in stores in the U.S.?

4. (Critical Thinking)
     What do the pandemics and the infections that medieval peoples suffered through have in
        common?

5. What would a scientist use Koch’s Postulates to prove?

6. E. coli is a bacteria that commonly lives in the human digestive tract.
     a) Is this E.coli an example of a phototroph, chemoautotroph, or chemoheterotroph?
          Explain.
     b) Would you expect E. coli to be aerobic, facultatively anaerobic, or obligately anaerobic?
          Explain.
     c) Under normal conditions would E. coli living in a human’s digestive tract be an example of           mutualism or commensalism or parasitism?                                   Explain your answer.
     (Extra Credit)
     d) Under ideal conditions E. coli can reproduce every 20 minutes. Assuming that ALL offspring           survive, how many offspring could 1 E. coli produce in 8 hours?
     e) Even though all people carry E. coli in their digestive tract,they can become extremely
          dangerous in the wrong situation. Describe a situation in which E. coli would be dangerous,
          or even fatal, inside the human body.

7. Geysers and hot springs contain water that has bubbled up from very deep underground. The      microorganisms found in these geysers are considered chemoautotrophs. What are they eating?

8. Anthrax is a soil bacteria that is an obligate anaerobe. Why don’t more farmers and gardeners      (people who work with the soil) contract the antrax disease more often?

9. (Critical Thinking)
Osmotic pressure can have a huge effect on single-celled organisms.
     a) Why would it most likely prove deadly to a protozoan to be removed from the Mississippi River           and placed in distilled water?
     b) What would happen to the red blood cells of a person who drinks ocean water?

10. A scientists places some bacteria into a clear broth. Within a few hours the broth starts to get      cloudy. About 3 days later the cloudiness starts to clear.
     a. 1) What is causing the broth to become cloudy?
         2) What phase of the growth curve does this demonstrate?
     b. 1) What is causing the broth to start to clear again?
         2) What phase of the growth curve does this demonstrate?

11. Very few bacteria are acidophiles. What does that mean happens to most bacteria that are
      taken in with your food and enter your stomach?

12. Few disease-causing microorganisms are thermophiles. Because of this one way that the
     human body fights infections is to produce a ………………………………. ?

PROJECT : MEASURING MICROBES
19. Assume you have a microscopes with both ocular and stage micrometers.
     a) Where is the ocular micrometer located?
     b) Where is the stage micrometer located?
     c) Which micrometer does not have the distance between its graduations change when the
          objective lenses change?

20. a) What is a counting chamber?
      b) Why are microbe samples often diluted before being placed into a counting chamber?

21. a) What is a spectrometer?
     b) What can be determined about a bacterial culture using “turbidity”?
     c) What is “Percentage of Transmission?