Microbiology Test #1 – Spring 2004

Name______

This test consists of two parts. In part one, answer four of the first five questions. In part two answer one of the two essays. Make sure you indicate which answers you want me to grade. Good luck and I will have these tests back to you on Tuesday.

Part One. Short Answers. Answer four of the following five questions (17.5 points each).

  1. Compare and contrast flagella to pili. Make sure you discuss both structure and function. Why are the structures of gram positive and gram negative flagella different?
  1. List and briefly describe three ways in which bacteria can regulate gene expression to adapt to environmental change, giving a specific example for each.
  1. 1) Draw a typical bacterial growth curve in laboratory medium. Label all of the phases. You do not need to explain what is happening in each phase – just give it a name. 2) Next, label where you might start to see spore formation – and explain why you have chosen that location. 3) Finally, penicillin is thought to influence the onset of one of these stages. Which one, and how?

  1. Briefly outline a series of steps that you would use to determine if a recent outbreak of ‘intestinal flu’ on a college campus was due to bacterial contamination in the sushi bar, and, if so, whether or not all of the student infections came from the same source. You do not have to write a detailed explanation – you could, for example, say ‘I’d do a spore stain to see if the microbe was a spore-former. If it was, the slide would have green spores.’
  1. The following three structures are for chemicals that we have discussed this semester. Identify all three, and then state if the substance has more of an impact on gram negative bacteria, gram positive bacteria, or an equal impact on both, and why.

.

Part Two. Essays. Choose one of the following two essays. Please circle the letter of the essay you have chosen. (30 points)

A.Is earth really the ‘planet of the microbes’? Argue for or against this statement using specific historical, genetic, environmental and human health examples.

  1. Basic biological research often seems irrelevant to individuals who get to decide what type of research gets funded (Congress, private foundations, taxpayers, etc…). Let’s say you have risen to the level of scientific advisor to your local senator. You are in a meeting with her, and she exclaims, “I cannot believe that the National Institutes of Health is spending $6 million just to determine how bacterial cells make DNA and proteins! We need to do something to make sure that taxpayer money is being spent on research that will actually benefit people – like finding cures for AIDS and cancer.” Giving at least three specific, well-described examples, convince your boss that basic microbiological research will benefit human health.