PRELABORATORY ASSIGNMENTS
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SET 1: Basic Microbial Techniques
Set 1: Basic Microbial Techniques:
1. Microscopy, Smear Prep, Motility:
2. Aseptic technique, Pure Culture& Subculture:
3. Staining: Simple stain, Gram stain, Negative stain, Capsule stain, Spore stain, Acid fast:
1. Describe three goals in preparing a good smear.
2. Describe two problems that result from using a thick smear of cells.
3. Identify two reasons for heat fixing a smear.
4. Describe how culture age plays a role in converting Gram positive organisms to Gram negative.
5. Name the bacterial cellular characteristic responsible for the Gram stain. Explain how this characteristic plays a role in staining Gram positive cells and not Gram negative cells.
6. Describe the medium used to detect motility. How do motile and nonmotile bacteria behave in this medium?
7. Compare the concentration of agar in solid media and semisolid media.
8. Name two genera that produce endospores.
9. Name two pathogenic acid-fast bacteria and the diseases they cause. What makes these cells resistant to staining?
10. Describe two reasons for cooling the nutrient agar to 50o C before inoculating and before pouring.
11. Describe the negative impact of splashing media onto the sides of a Petri plate.
12. Discuss the reasons for flaming the loop before entering the culture and after the inoculation.
13. Name the two methods for obtaining a pure culture. Describe one advantage to using the pour plate method and one advantage to using the streak plate method.
14. Describe the composition of a pure colony.
15. When inoculating a Petri plate how should you handle the cover?
16. Describe the position of plates during incubation. How does this preserve the isolation?
17. Describe two advantages to using agar as a medium.
18. Identifying the melting and solidifying temperatures for agar.
19. Define turbidity.