NSB 230 – MICROBIOLOGY
CHAPTER 3 – STUDY GUIDE
1. What are the six “Is”, basic techniques to study microorganisms in the laboratory?
2. Define magnification in the context of microscopy.
3. How do you calculate the total magnification of the image you observe when using a light microscope?
4. What is the difference between the real image and the virtual image produced by a light microscope?
5. Define resolving power
6. Why is resolving power important?
7. What two parameters define the resolution of a microscope?
8. Why do we add oil to a slide when we want to use the oil immersion lens?
9. Name the different types of light microscopes
10. What is the main difference between light microscopy and electron microscopy?
11. Briefly describe the two different types of electron microscopy.
12. What factors should be taken into account when preparing a specimen to be observed with a
microscope?
13. Which techniques can be used to observe a fresh preparation? Briefly describe each
14. What is a fixed mount?
15. What is the function of staining in light microscopy?
16. Describe the smear technique. Why do we heat fix a smear?
17. What are basic dyes? What are acidic dyes?
18. What is the difference between a positive and a negative stain?
19. What is the difference between a simple stain and a differential stain?
20. Enumerate and briefly describe the differential stains studied in class.
21. What is a structural stain? Name and describe two.
22. Define inoculation.
23. What does the term “viable but nonculturable” means?
24. Describe the different incubation factors that should be taken into account when growing
microorganisms
25. What is a microbial colony?
26. In general, how do we achieve isolation?
27. Briefly describe the three different techniques for isolation of microbial cells
28. Describe:
a. Pure (axenic) culture
b. Mixed culture
c. Contaminated culture
d. Second-level culture
29. What are the different ways you can identify a microorganism?
30. Describe the sterile technique.
31. Which are the properties of media used for their classification?
32. Enumerate and describe the different physical states of microbiological media
33. What is the advantage of a liquefiable solid media over a nonliquefiable one?
34. What is agar? Enumerate its benefits for microbiological experimentation.
35. What is the difference between synthetic and complex media?
36. Define general purpose media
37. Define enriched medium
38. What are growth factors?
39. What is selective media? Give two examples.
40. What is differential media? Give two examples.
41. Can a medium be both selective and differential? Explain
42. What is the purpose of a reducing medium?
43. What is the purpose of a carbohydrate fermentation medium.
44. Why do we use an inverted Durham tube in certain media?
45. Why would we need a transport media?
46. What is the purpose of an assay media?
47. What is the purpose of an enumeration media?