Short Answer Questions for Exam 1, Biology 250

  1. In what kingdom of living things are bacteria classified?
  2. How are the bacteria different from organisms in the other kingdoms?
  3. What is an obligate intracellular parasite? Give an example.
  4. What three conditions must be optimized to see bacteria with a visible light microscope?
  5. Which of the three conditions above does an oil immersion lens improve?
  6. What characteristics of bacteria can you determine using a simple stain and a visible light microscope?
  7. If you inoculate a tube of sterile culture media with bacteria and incubate it, how could you tell whether they grew?
  8. How could you separate a mixture of organisms into pure cultures of each organism?
  9. How could you determine whether an organism can break down a particular nutrient (e.g., glucose) to produce acid and/or gas?
  10. Give an example of an organism that is normal flora in most humans, and one that is a pathogen. What do normal flora and pathogen mean?
  11. How are visible light microscopes and electron microscopes different? How do these differences improve our ability to observe the characteristics of bacterial cells?
  12. What structures are included in the bacterial envelope?
  13. For all the bacterial structures discussed in class, know the general chemical composition, function, and significance in the disease process, if any.
  14. Describe the process of phagocytosis.
  15. Is the possession of a capsule of greater benefit to the host organism or to the bacterium that possesses it? Give an example.
  16. How do Gram-positive and Gram-negative cell walls differ? Why do Gram-positive and Gram-negative cells stain differently?
  17. Why does penicillin affect Gram-positive cells more than Gram-negative ones?
  18. Describe several different arrangements of flagella in bacteria.
  19. Explain three different functions of pili.
  20. How are plasmids involved in antibiotic resistance and genetic engineering?
  21. What advantage do bacteria that can undergo sporogenesis (become endospores) have over those that can't? Describe the steps in the process of sporogenesis.
  22. Give at least four differences between prokaryotic and eukaryotic cells. In what respects are prokaryotic cells simpler than eukaryotic cells? In what respects are they more complex?
  23. What elements/compounds are essential for bacterial survival?
  24. Would you expect a facultative autotroph like E. coli to grow faster or slower in an environment that provides only glucose and inorganic nutrients than in one that is rich in preformed organic materials? Why?
  25. Define:
    1. Having to do with C source: strict autotroph, facultative autotroph, heterotroph
    2. Having to do with oxygen preference: strict aerobe, aerobe, facultative anaerobe, anaerobe, oxygen tolerance
    3. Having to do with carbon dioxide preference: capnophile
    4. Having to do with salt preference: halophile
    5. Having to do with pH preference: acidophile
    6. Having to do with temperature preference: mesophile, psychrophile, thermophile
    7. Having to do with energy source: chemotroph, phototroph (litho-, organo-)
  26. Give examples of a facultative anaerobe, a strict anaerobe, an endospore former, an organism that tolerates a very alkaline pH, and an acidophile.
  27. What is the difference between a temperature (or pH) optimum and a temperature (or pH) range?
  28. In what phase of the growth curve is/does a culture:
    1. most sensitive to antibiotics?
    2. have the maximum amount of nutrients?
    3. have the maximum amount of accumulated waste products?
    4. have equal #'s of dividing and dying cells?
    5. make endospores?
  29. Give four examples of organisms that ferment glucose and name the products of their fermentation.
  30. Why is it advantageous for bacteria to break down glucose by aerobic respiration rather than fermentatively if they can? (requires Krebs/TCA cycle, electron transport system, and usually oxygen)
  31. What is the ATP produced from breaking down glucose or other nutrients used for?
  32. Why is it reasonable to call ATP an energy currency?
  33. Define: enzyme, substrate, product