Micro Exam 2

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Exam II Microbiology spring 2011 chapters 5, 6, and 7: all answers on scantron

1. Which of the following compounds is NOT an enzyme? A) Dehydrogenase B) Cellulase C) Coenzyme A D) -galactosidase E) Sucrase 2. Which organism is NOT correctly matched to its energy source? A) Photoheterotroph light B) Photoautotroph CO2 C) Chemoautotroph Fe2+ D) Chemoheterotroph glucose E) Chemoautotroph NH3 3. Which of the following statements about anaerobic respiration is false? A) It involves glycolysis only. B) It involves the Krebs cycle. C) It involves the reduction of nitrate. D) It generates ATP. E) It requires cytochromes.

4. What type of reaction is above? A) Decarboxylation B) Transamination C) Dehydrogenation D) Oxidation E) Reduction 5. What is the fate of pyruvic acid in an organism that uses aerobic respiration? A) It is reduced to lactic acid. B) It is oxidized to acetyl CoA C) It is oxidized in the electron transport chain. D) It is catabolized in glycolysis. E) It is reduced in the Krebs cycle.

6. How would a noncompetitive inhibitor interfere with a reaction involving the enzyme shown in the figure above? A) It would bind to a. B) It would bind to b. C) It would bind to c. D) It would bind to d. E) Can't tell.

7. How is ATP generated in the reaction shown in the figure above? A) Glycolysis B) Fermentation C) Photophosphorylation D) Oxidative phosphorylation E) Substrate-level phosphorylation 8. Which of the following is the best definition of oxidative phosphorylation? A) Electrons are passed through a series of carriers to O2. B) The energy released as carrier molecules are oxidized is used to generate ATP. C) The energy released in the reduction of carrier molecules is used to generate ATP. D) The transfer of a high-energy phosphate group to ADP. 9. Which of the following statements about substrate-level phosphorylation is false? A) It involves the direct transfer of a high-energy phosphate group from an intermediate metabolic compound to ADP. B) No final electron acceptor is required. C) It occurs in glycolysis. D) The oxidation of intermediate metabolic compounds releases energy that is used to generate ATP. E) It occurs in the Krebs cycle.

10. Which of the following statements about photophosphorylation is false? A) Light liberates an electron from chlorophyll. B) The oxidation of carrier molecules releases energy. C) Energy from oxidation reactions is used to generate ATP from ADP. D) It requires CO2. E) It occurs in photosynthesizing cells. 11. A strictly fermentative bacterium produces energy A) By glycolysis only. B) By aerobic respiration only. C) By fermentation or aerobic respiration. D) Only in the absence of oxygen. E) Only in the presence of oxygen. 12. The advantage of the pentose phosphate pathway is that it produces all of the following EXCEPT A) Precursors for nucleic acids. B) Precursors for the synthesis of glucose. C) Three ATPs. D) NADPH. E) Precursors for the synthesis of amino acids. 13. In noncyclic photophosphorylation, O2 is produced from A) CO2. B) H2O. C) C6H12O6. D) Sunlight. E) Chlorophyll. 14. Which of the following is the best definition of fermentation? A) The reduction of glucose to pyruvic acid B) The oxidation of glucose with organic molecules serving as electron acceptors C) The complete catabolism of glucose to CO2 and H2O D) The production of energy by substrate-level phosphorylation E) The production of ethanol from glucose 15. Which of the following is NOT necessary for anaerobic respiration? A) Cytochromes B) Flavoproteins C) A source of electrons D) Oxygen E) Quinones

16. In green and purple bacteria, electrons to reduce CO2 come from A) CO2. B) H2O. C) C6H12O6. D) Sunlight. E) Chlorophyll. 17. Assume you are growing bacteria on a lipid medium that started at pH 7. The action of bacterial lipases should cause the pH of the medium to A) Increase. B) Decrease. C) Stay the same. 18. Which of the following uses CO2 for carbon and H2 for energy? A) Chemoautotroph B) Chemoheterotroph C) Photoautotroph D) Photoheterotroph 19. Which of the following uses glucose for carbon and energy? A) Chemoautotroph B) Chemoheterotroph C) Photoautotroph D) Photoheterotroph 20. Which of the following has bacteriochlorophylls and uses alcohols for carbon? A) Chemoautotroph B) Chemoheterotroph C) Photoautotroph D) Photoheterotroph 21. Cyanobacteria are a type of A) Chemoautotroph. B) Chemoheterotroph. C) Photoautotroph. D) Photoheterotroph 22. Which statements are true? 1Electron carriers are located at ribosomes. 2ATP is a common intermediate between catabolic and anabolic pathways. 3ATP is used for the long-term storage of energy and so is often found in storage granules. 4Anaerobic organisms are capable of respiration. 5ATP is generated by the flow of protons across the cell membrane. A) 2, 4, 5 B) 1, 3, 4 C) 2, 3, 5 D) 1, 2, 3 E) All

C2H5OH Ethanol

CH3COOH Acetic acid

23. Which of the following is true about the reaction above? A) This process requires O2. B) This process occurs anaerobically.C6H12O6 2C2H5OH + 2CO2 Glucose Ethanol 24. Which of the following is true about the reaction above? A) This process requires O2. B) This process occurs anaerobically.

25. Beggiatoa bacteria get energy by oxidizing S2- to S6+. This means they take ________ for their ________. A) electrons; electron transport chain B) electrons; fermentation C) protons; NAD+ D) sulfur; photophosphorylation E) glucose; glycolysis 26. A bacterial culture grown in a glucose-peptide medium causes the pH to increase. The bacteria are most likely A) Fermenting the glucose. B) Oxidizing the glucose. C) Using the peptides. D) Not growing. 27. A urease test is used to identify Myobacterium tuberculosis because A) Urease is a sign of tuberculosis. B) M. tuberculosis produces urease. C) Urea accumulates during tuberculosis. D) Some bacteria reduce nitrate ion. E)M. bovis can cause tuberculosis.

28. ) In Figure 6.1, which line best depicts a facultative anaerobe in the absence of O2? A) a; B) b; or C) c

figure 6.1

29. In Figure 6.1, which line best depicts an obligate anaerobe in the presence of O2? A) a B) b C) c 30. In Figure 6.1, which line best depicts Neisseria gonorrhea when growing inside the human body? A) a B) b C) c 31. The addition of which of the following to a culture medium will neutralize acids? A) Buffers B) Sugars C) pH D) Heat E) Carbon 32. Salts and sugars work to preserve foods by creating a A) Depletion of nutrients. B) Hypotonic environment. C) Lower osmotic pressure. D) Hypertonic environment. E) Lower pH. 33. The term facultative anaerobe refers to an organism that A) Doesn't use oxygen but tolerates it. B) Is killed by oxygen. C) Uses oxygen or grows without oxygen. D) Requires less oxygen than is present in air. E) Prefers to grow without oxygen 34. Which of the following is an advantage of the standard plate count? A) Can readily count cells that form aggregates B) Requires incubation time C) Determines the number of viable cells D) Chemical and physical requirements are determined by media and incubation. E) Cannot be used to count bacteria in food 35. Thirty-six colonies grew in nutrient agar from 1.0 ml of undiluted sample in a standard plate count. How many cells were in the original sample? A) 4 B) 9 C) 18 D) 36 E) 72

figure 6.236. In Figure 6.2, which section shows a growth phase where the number of cells dying equals the number of cells dividing? A) a B) b C) c D) d E) a and c 37. In Figure 6.2, which sections of the graph illustrate a logarithmic change in cell numbers? A) a and c B) b and d C) a and b D) c and d E) b only 38. A culture medium on which only gram-positive organisms grow and a yellow halo surrounds Staphylococcus aureus colonies is called a(n) A) Selective medium. B) Differential medium. C) Enrichment culture. D) A and B E) B and C 39. A culture medium consisting of agar, human blood, and beef heart is a A) Chemically defined medium. B) Complex medium. C) Selective medium. D) Differential medium. E) Reducing medium.

figure 6.3 40. Figure 6.3 shows three containers of water connected by tubes. A selectively permeable membrane divides each tube. Solutes are added to each container to give final concentrations of 5% NaCl in (a); 10% NaCl in (b); and 5% sucrose in (c). When the experiment is first set up, the initial movement of water will be A) a to b; b to c; c to a. B) a to b; c to b; c to a. C) a to c; b to c; c to a. D) a to c; c to b; c to a. E) b to a; b to c; c to a.41. Which of the following pairs is mismatched? A) Psychrotroph growth at 0C B) Thermophile growth at 37C C) Mesophile growth at 25C D) Psychrophile growth at 15C E) Hyperthermophiles growth at 100C 42. During which growth phase will gram-positive bacteria be most susceptible to penicillin? A) Lag phase B) Log phase C) Death phase D) Stationary phase E) The culture is equally susceptible during all phases.

43. Which of the following is the best definition of generation time?

A) The length of time needed for lag phase B) The length of time needed for a cell to divide C) The minimum rate of doubling D) The duration of log phase E) The time needed for nuclear division 44. Which of the following is NOT a direct method to measure microbial growth? A) Direct microscopic count B) Standard plate count C) Filtration D) Metabolic activity E) MPN 45. Which group of microorganisms is most likely to spoil a freshwater trout preserved with salt? A) Psychrophiles B) Facultative halophiles C) Anaerobes D) Thermophiles E) Hyperthermophiles 46. Which of the following is an organic growth factor? A) Glucose B) NAD+ C) Peptone D) NH4H2PO4 E) H2O 47. Which of the following is an example of a metabolic activity that could be used to measure microbial growth? A) Standard plate count B) Glucose consumption C) Direct microscopic count D) Turbidity E) MPN 48. An experiment began with 4 cells