Microbiology, old exam 1 questions

Some sample exam questions - Please don't ask me for the answers to these questions, finding the answers is up to you!!

1. Bifidobacterium bifidum is commonly the dominant bacterium in the intestines of breast-fed infants because....
a. breast milk contains specific amino sugars and lactulose that B. bifidum feeds on.
b. babies eat a lot of yogurt.
c. breast milk contains millions of B. bifidum cells per cubic centimeter.
d. all of the above

2. Which types of cell walls are not found in the Methanogen subdivision of the Archaea?
a. peptidoglycan
b pseudopeptidoglycan ("pseudomurein")
c. protein
d. glycoprotein
e. all of the above

3. Methanogens play an important role in the world because they are
a. the only organisms that can breakdown methane (CH4).
b. usually the terminal step in anaerobic food chains that lead to the decomposition of organic matter.
c. the dominant organism in animal guts and can cause several diseases.
d. the major cause of stinky flatulence.

5. A phylogenetic system of classifying organisms is also called a natural system and should be based on
a. evolutionary relationships among organisms
b. structural and morphological similarities among organisms
c. the biases and preconceptions of individual scientists
d. the idea that large organisms should be studied more intensively than small ones

6. Microbes are the dominant form of life on Earth. About ______% of the mass of all living things on earth are microscopic.
a. 10 b. 30 c. 50

7. Some Acetic Acid Bacteria can produce extracellular cellulose fibers. A logical explanation for this is that these fibers
a. protect the cells from the lactic acid in vinegar.
b. help these bacteria float so that they can be closer to a source of O2.
c. gross people out so that they won't drink vinegar.
d. all of the above.

8. The tree of life that we use in this class is based mostly on the
a. sequence of nucleotides in the RNA of one of the ribosomal subunits
b. the total sequence of the nucleotides in each organism
c. the % G+C in the DNA of each organism

9. Which of the following pairs is mismatched?
a. Hooke - 30 x magnification
b. Leeuwenhoek - 300 x magnification
c. Pasteur - 10,000 x magnification
d. Redi - spontaneous generation

13. Predatory bacteria in the Proteobacterial group include
a. Caulbacter and Bdellovibrio
b. Bdellovibrio and Myxobacteria
c. Propionibacterium and Bifidobacterium
d. Agrobacterium and Acetobacter

14. Salmonella, Escherichia, and Serratia are all members of the Gamma Proteobacteria and can
a. grow aerobically and anaerobically
b. only live in the absence of oxygen
c. only live in the presence of oxygen
d. grow only aerobically

15. Many bioluminescent bacteria can use their ________ capabilities to live in the guts of fish and their _______ abilities to live in the light organs of fish or to survive in the aerobic waters of the open oceans.
a. aerobic/anaerobic
b. anaerobic/aerobic

16. Which of the following pairs is mismatched?
a. Koch - anthrax
b. Winogradsky - chemoautotrophs
c. Beijerinck - small pox
d. Hesse - agar

17. In a homofermentative lactic acid bacterium
a. 2 lactic acids are produced for every glucose that is fermented
b. 2 acetic acids are produced for every glucose that is fermented
c. 1 acetic acid, 1 ethanol and 1 carbon dioxide are produced for every glucose that is fermented
d. 1 lactic acid, 1 ethanol and 1 carbon dioxide are produced for every glucose that is fermented
e. c or d

18. Paul Ehrlich's researches into chemotherapy were inspired by his observations that
a. pathogenic bacteria are always associated with a diseased organism.
b. certain stains are preferentially taken up by microbes
c. there is a zone of clearing around actinomycetes when they are cultured with other bacteria.
d. patients with syphilis got better if they drank a lot.

19. Eucarya and Archaea share many characteristics including
a. similar RNA polymerases
b. immunity to many antibiotics that affect most Bacteria
c. similar methods of transcribing proteins
d. all of the above

20. The 16S/18S phylogenetic tree supports which of the following theories?
a. That the earth was cold when life evolved
b. That most early forms of life needed oxygen
c. The endosymbiotic theory of mitochondrial origin
d. That ribosomes evolved late in the history of life

21. Plasma membranes with fatty acids linked to glycerol via ester linkages are found in
a. Bacteria & Eucarya
b. Bacteria and Archaea
c. Archaea and Eucarya
d. all of the above

22. % G + C stands for
a. the percentage of guanine and cytosine in the DNA of an organism.
b. the percentage of guanine and cytosine in the proteins of an organism.
c. the sequence of guanine and cytosine in the rRNA of an organism.
d. all of the above.

23. Which of the following bacteria are commonly isolated from human feces?
a. Bifidobacterium bifidum
b. Escherichia coli
c. Lactobacillus acidophilus
d. Lactobacillus delbrueckii subsp. bulgaricus
e. a, b and c
f. a, c and d

24. Briefly describe why Tyndallization or intermittent sterilization can be used to sterilize soil or hay infusions. (5 pts.)

25. Draw and label the life cycle of any genus of low GC gram + bacteria that form endospores. Please state which genus you are describing and whether it is an aerobe or an anaerobe. (5 pts.)


26. Draw and label a gram + and a gram - cell wall. Be sure and include the plasma membranes in your drawings. (6 pts.)

29. State Koch's postulates in your own words. (4 pts.)

31. Which pair is most closely related in a phylogenetic sense?
a. animals and flagellated protozoa
b. animals and slime molds
c. animals and Diplomonads
d. animals and fungi

32. Bacterial flagella cause bacteria to move by
a. whipping
b. vibrating
c. rotating

33. The most complex and elaborate spore bearing structures are produced by which genus of the high GC gram + bacteria?
a. Staphylococcus
b. Arthrobacter
c. Streptococcus
d. Streptomyces

34. Most commercially important antibiotics come from
a. low GC gram + bacteria and fungi
b. fungi and high GC gram + bacteria
c. Proteobacteria and low GC gram + bacteria
d. enteric bacteria and fungi.

35. The low GC group of the gram positive bacteria are mostly filamentous.
a. true. b. false.

36. Members of the genus Pseudomonas have _______ flagella and are oxidase _______ .
a. peritrichous / negative
b. polar / negative
c. peritrichous / positive
d. polar / positive

37. In membranes of Archaea, isoprenoid units are attached to glycerol by:
a. ether linkages
b. ester linkages
c. peptide bonds
d. either a or b

38. Bacterial flagella are
a. composed of microtubules hooked to flagellin
b. floppy structure made of flagellin
c. rigid structures made of flagellin

40. Draw the "Tree of Life" (label the 3 main branches) and place the following major groups of organisms on it: (8 pts.)

Fungi, Animals, Extreme Halophiles, Mitochondria, Extreme Thermophiles, Proteobacteria, Methanogens, and Gram + Bacteria
.

Attention:
The following contains information that might appear on exam 1.

Please read this brief article from "Science News" for more information on probiotics.