Microbiology Test #1 – Spring 2013
Name_________________________________________________
This test consists of 2 parts. In part 1 (75 points), answer 5 of the 6 questions, clearly indicating the questions you want me to grade. In part 2 (25 points), answer all parts of the essay completely.
Introduction: You work in a bio-prospecting laboratory, and have found a potentially new species of thermophilic microorganism that you isolated from a steaming compost pile at the Susquehanna University community garden. Ultimately, you are hoping that the microbe can be sold to home gardeners as a new, organic compost starter, so that you can become SU’s newest multimillionaire alumnus. However, you have a lot of work to do first!
Part One . Short Answers. Answer five of the following six questions (15 points each) using only the space provided for each question. Please note that I am well aware that several of the questions have many possible correct answers, and that I have no doubt whatsoever that you know them all. HOWEVER, please do NOT give more correct answers than the question calls for! These are intended to be short answers, not mininovels 

Question 1: You have been asked to analyze the new species microscopically. Choose two different types of microscopes – and justify your choices by stating how the images generated by each (and thus the information that you would get from the images) would differ. Also state whether or not you would need to perform any specific preparation on the microbe before visualizing it.
Question 2: You Gram-stain the microbe and see a long red rod. Is this microbe Gram-
Positive or Gram-Negative? Given your answer, and assuming that your microbe is from domain Bacteria, list all of the components of the cell wall. You do not need to explain them at all. How would your answer have differed if your microbe was Archaeal?

MinE
MreB
FtsZ
FtsI
Question 3.
Your microorganism is a chemolithotrophic, obligate aerobe, in addition to being a thermophile. Briefly describe how you would grow it in a chemostat.
Question 4.
What would you expect the phenotype of your bacterium to be if you mutated the following genes. Be brief but specific . Each of these genes would give a different phenotype.

c. b. a.
Question 5.
Name and give a microbiological function for each of the structures below.

Question 6.
Describe how you would use Koch’s postulates to determine if your microbe is responsible for the odd black precipitate in the medium in which you grow it.

Part Two. Essays.
Answer either essay A or essay B essay completely. (25 points)
Essay A.
Your lab partner is working on a psychrophile that she isolated from the laboratory refrigerator. It is a Gram-positive rod, too. Nevertheless, you know that surface appearances can be quite deceiving, and that it is quite unlikely that your two bacteria are closely related either genetically or metabolically.
1.
Briefly describe how you would determine how closely related the two bacteria really are (genetically).
2.
Next, choose three structures and/or metabolic processes that you expect would differ between your two microbes, given their adaptations to their respective environments, and clearly describe how you expect the two microbes to with respect to these structures/processes.
Essay B.
Your microbe is definitely motile, and appears to have peritricous flagella that it uses to swim towards food sources. Describe 1) the detailed structure of its flagella, 2) how the microbe generates energy to rotate its flagella, 3) the molecular interactions that cause the flagella to rotate and 4) how the microbe uses its flagella to swim ‘towards’ its food. What is this process called?