Microbiology 2124
Exam 3
Nov. 23, 1998
David Demezas

General Instructions: Answer multiple choice questions on the test sheet. Answer other questions in the space provided on the test sheet. Be sure that you answer the question in complete sentences. Write your name on all pages of the test.
Multiple Choice (2.5 pts each). Choose the most correct answer and mark the corresponding letter on the blank provided to the left of the question.

1. Which gene is used routinely to determine the phylogenetic relationship among bacteria?
A. beta-galactosidase
B. 5S rRNA
C. tryptophan tRNA
D. 16S rRNA
E. DNA polymerase

2. Which of the following do not include anoxic phototrophic species of bacteria?
A. Green sulfur bacteria
B. Green non sulfur bacteria
C. Purple non sulfur bacteria
D. Purple sulfur bacteria
E. Cyanobacteria

3. Which of the following types microorganisms would be enriched in a basal salts medium supplemented with bicarbonate, vitamin B12, sodium sulfide (0.1% w/v) and a weak light source.
A. Purple non sulfur bacteria
B. Cyanobacteria
C. Green sulfur bacteria only
D. Purple sulfur bacteria only
E. Purple sulfur and green sulfur bacteria

4. The site of nitrogen fixation in most cyanobacteria is in the _____.
A. akinete
B. heterocyst
C. hormogonium
D. vegetative cell
E. cyanophycin

5. True or false: Chemolithotrophs are predominantly aerobic microorganisms that generate ATP by the oxidation of reduced inorganic compounds.

6. Nitrifiers carry out which of the following ecological functions in soils?
A. Reduction of ammonia to nitrate
B. Oxidation of methane to methanol
C. Reduction of sulfate to sulfide
D. Oxidation of ammonia to nitrate
E. Oxidation of hydrogen gas to protons

7. Sulfate-reducing bacteria are widely distributed in nature. Which of the following would not be proper for enrichment medium used for their isolation?
A. a lactate-sulfate medium
B. ascorbate or thioglycolate
C. ferrous iron
D. incubation under aerobic conditions

8. Which of the following is a Gram-positive, endospore-forming microorganism that produces an insecticidal protein?
A. Pseudomonas sp.
B. Azotobacter sp.
C. Bacillus sp.
D. Chromobacterium sp.
E. Klebsiella sp.

9. Escherichia, Enterobacter, Shigella, and Salmonella are all members of the group of bacteria called _______.
A. colonic bacteria
B. stomach bacteria
C. enteric bacteria
D. hemmorhagic bacteria
E. planktonic bacteria

10. Species of Halobacterium may use which of the following for energy?
A. light-driven ATP production
B. Fermentation
C. Oxidation of organic compounds
D. only A and B
E. A, B and C are correct.

11. _____________, a membrane-associated protein, plays an integral role in the generation of a proton motive force to drive ATP synthesis in Halobacterium.
A. carotenoids
B. bacteriorhodopsin
C. ATPase
D. cytochrome oxidase
E. catalase

12. True or False? Methanogens are obligate aerobes.

13. All hyperthermophilic Archaea have a temperature optimum _______.
A. between 50 and 80 ^oC
B. above 80 ^oC
C. below 50 ^oC

14. Hyperthermophiles produce large amounts of ______ as an adaptation to their extreme environment.
A. 2,3 diphosphoglycerate
B. water
C. glucose
D. pyruvate
E. citrate

15-18 Matching. Match the correct description with the genus of bacteria.

15. Methanopyrus

16. Thermoplasma

17. Archaeoglobus

18. Pyrodictium

19. Which type(s) of metabolism is/are found in the algae?
A. phototrophy
B. chemoorganotrophy
C. photoheterotrophy
D. only A and C
E. A, B, and C

20. Which type(s) of metabolism is/are found in the fungi?
A. photoautotrophy
B. chemolithotrophy
C. chemoorganotrophy
D. photoheterotrophy
E. A, C, and D

21. Which of the following fungi does not produce spores?
A. Deuteromycetes
B. Oomycetes
C. Zygomycetes
D. Basidiomycetes
E. Ascomycetes

22. True or False? Yeasts reproduce by budding.

23. Which of the following is a signal for slime molds to aggregate?
A. cAMP
B. riboflavin
C. ATP
D. glucose
E. 6-phosphofructose

24. The usual mode for protozoa to obtain food is by _____.
A. autotrophy
B. phototrophy
C. phagotrophy
D. lithotrophy
E. None of the above

25. Which of the following groups of protozoa includes the foraminiferas that compose the White Cliffs of Dover?
A. Mastigophora
B. Sarcodina
C. Ciliphora
D. Sporozoa

26. Which of the following protozoan groups may cause infectious disease in humans?
A. Mastigophora
B. Sarcodina
C. Ciliphora
D. Sporozoa
E. All of the above

27. Which of the following is an asexual spore?
A. basidiospore
B. ascospore
C. conidia
D. oospore
E. zygospore

28. Bacteriophage can be enumerated using the __________.
A. restriction endonucleases
B. coliform alert
C. Ames test
D. plaque assay
E. None of the above

29. Bacteria use _________ to cleave and destroy incoming DNA such as viral DNA.
A. polymerases
B. restriction endonucleases
C. ligases
D. primases
E. telomerases

30. Retroviruses are RNA viruses that contain _____________ to synthesize DNA from their RNA upon infection of the host cell.
A. DNA polymerase
B. RNA polymerase
C. reverse transcriptase
D. Taq polymerase
E. none of the above

31. Which of the following viruses is/are a male-specific virus(es) that attach to the F-pili?
A. MS2
B. lambda
C. M13
D. lambda and M13
E. MS2 and M13

32. Negative strand RNA viruses must synthesize a positive strand RNA that is translated into proteins. What enzyme do these viruses use to synthesize a positive strand RNA?
A. DNA dependent DNA polymerase
B. RNA dependent DNA polymerase
C. RNA dependent RNA polymerase
D. DNA dependent RNA polymerase

33. The temperate virus lambda DNA may integrate into the host bacterium's chromosome. Lambda is now referred to as a _________.
A. lysogen
B. prophage
C. plasmid
D. cosmid
E. transposon

34. Identify the virus game! "Other bacteriophage might "think" me weird because of my unusual shape since I am linear and skinny, although my DNA is circular. I am not very versatile with regards to hosts- I associate only with male E. coli. I am rather gentle to my host since I do not induce lysis, and therefore do not form obvious plaques. Gene jockeys like to us me as a producer of cloned single-stranded DNA since all of my rather small genome is not required for my survival and my host's factory remains intact. WHO AM I?"
A. T4 Bacteriophage
B. T7 Bacteriophage
C. Phi Chi 174
D. M13
E. lambda

35. Which two viruses use the rolling circle mechanism during replication?
A. phi chi 174 and lambda
B. M13 and MS2
C. T7 and MS2
D. phi chi 174 and T7
E. M13 and T7

36. Which two proteins play a central role in deciding whether lambda phage enters the lysogenic state or the lytic cycle?
A. cro and CI (lambda repressor)
B. cro and N
C. CII and N
D. CII and CIII
E. N and CIII

37. True or False? Catabolite repression plays a role in the decision making process for lambda to enter the lytic cycle or lysogenic state.

38. True or False? Antibiotics are secondary metabolites.

39. Vitamin B12 is made exclusively by microorganisms. Commercially B12 is synthesized by _________.
A. Bacillus species
B. Propionibacterium species
C. Streptomyces species
D. Ashbya species
E. Rhizopus species

40. Lambda cohesive (cos) site cloned into a plasmid results in a _______.
A. new bacteriophage
B. cosmid
C. phagemid
D. yeast artificial chromosome
E. none of the above.

41. (10 pts) Complete the following table.

42. (10 pts) Most hyperthermophiles are obligate anaerobes; some species of the hyperthermophile Acidianus are facultative aerobes. Acidianus uses elemental sulfur when growing aerobically and anaerobically. Briefly explain the role of elemental sulfur when Acidianus is growing a) aerobically and b) anaerobically.

43. (10 pts) Draw a one-step growth curve of viruses. Be sure to label both the x and y axis correctly. In your drawing clearly indicate the latent and maturation periods.