Aseptic Technique and Culturing Microbes

Exercise 1: Culturing Microbes in Broth

Questions

A. What is the purpose of wiping down your work area with bleach before and after an experiment?

B. List five safety precautions you used to protect yourself while culturing microbes.

C. What is the purpose of a broth in a microbiology laboratory? 

D. Did each of your cultures develop at the same rate? Why might your incubation environment favor one microbe over another?

Exercise 2: Isolating Individual Colonies

Questions

A. What is a colony and how does a colony relate to a bacterial cell? Why are colonies important in the study of microbiology?

B. Are bacteria easier to observe on a plate or in a broth? How do the bacteria look on the plate as compared to the broth?

C. How could you tell if one of the colonies on your pure plate was a contaminant from the environment and did not come from your original culture?

D. Was the streak plate method effective at diluting the population size in all 4 plates? How could your methods be improved in the future?

Bacterial Enumeration-Dilutions and Plate Counts

Exercise 1: Dilutions and Viable Plate Counts

Questions

A. What is a colony forming unit and how is it used to infer microbial numbers in a sample?

B. Why are plate counts of 30-300 considered viable?

C. If you allowed your dilution tubes to incubate for 24 hours before plating them, do you think the results of the experiment would be impacted? Assume that unlimited resources are present in the tubes. Explain your answer.

Attachment:- Assignment Files.rar