Multiple Choice Quiz
Multiple Choice Quiz
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 1 Thirty-six colonies grew in nutrient agar from 1.0 ml of sample withdrawn from a solution diluted to 10-5 in a standard plate count procedure. How many cells were in the original sample? A) 360 B) 3,600 C) 360,000 D) 1,800,000 E) 3,600,000 2 Thirty-six colonies grew in nutrient agar from 0.1 ml of sample withdrawn from a solution diluted to 10-3 in a standard plate count procedure. How many cells were in the original sample? A) 360 B) 3,600 C) 360,000 D) 1,800,000 E) 3,600,000 3 Which of the following is the best definition of generation time? A) The length of time it takes for lag phase. B) The length of time it takes for a population of cells to double. C) The maximum rate of doubling divided by the initial count. D) The duration of log phase. E) The time it takes for nuclear division. 4 An experiment began with 4 cells and ended with 128 cells. How many generations did the cells go through? A) 64 B) 32 C) 6 D) 5 E) 4 5 If you start out with a population density of 200 CFU/ml of a bacterium that divides every 20 minutes, what will the population density be at the end of two hours, assuming the cells are in the log phase of growth. A) 1200 CFU/ml B) 26 CFU/ml C) 3200 CFU/ml D) 12800 CFU/ml E) 2006 CFU/ml

Use this typical bacterial growth curve to answer the following question.

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 6 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 7 Which section shows a growth phase where the number of cells dying is greater than the number of cells dividing? A) A B) B C) C D) D E) A and C 8 Which section shows a growth phase where the cells dividing at their maximum rate of division? A) A B) B C) C D) D E) A and C 9 If you start out with a population density of 200 CFU/ml of a bacterium that divides every 30 minutes, what will the population density be at the end of two hours, assuming the cells are in the log phase of growth. A) 800 CFU/ml B) 24 CFU/ml C) 3200 CFU/ml D) 12800 CFU/ml E) 2004 CFU/ml 10 A culture of bacteria produces 5 generations in 2 hours. What is the generation time for this bacterium under those conditions. A) 15 minutes B) 24 minutes C) 30 minutes D) .75 hours E) 1 hour 11 A bacterial population increases from 100 to 100,000,000 in 15 hours. What is the generation time of this culture? A) 30 minutes B) 45 minutes C) 60 minutes D) 2 hours E) Not enough information to determine the generation time 12 Starvation proteins are produced by a culture during which of the following parts of the growth curve? A) Lag phase B) Exponential phase C) Stationary phase D) Balanced growth phase E) Death phase 13 Which of the following is used to grow bacterial cultures continuously? A) Chemostat B) Coulter Counter C) Hemostat D) Petroff-Hausser chamber E) Bacteria cannot be grown in continuous culture 14 Which of the following procedures uses a photocell to measure absorbance of a culture to regulate the flow of culture media? A) Chemostat B) Coulter Counter C) Hemostat D) Petroff-Hausser chamber E) Trubidostat 15 An organism is completely dependant on atmospheric O2 for growth. This organism is a(n) A) osmotolerant. B) acidophile. C) facultative anaerobe. D) aerotolerant anaerobe. E) obligate aerobe. 16 An organism has an optimal growth rate when the hydrogen ion concentration is very high. This organism is a(n) A) osmotolerant. B) acidophile. C) neutrophile. D) aerotolerant anaerobe. E) alkalophile. 17 An organism that expends energy to grow in a habitat with a low water activity in order to maintain internal solute concentrations to retain water is A) osmotolerant. B) acidophile. C) neutrophile. D) aerotolerant anaerobe. E) alkalophile. 18 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 when present or grows without oxygen when oxygen is absent. D) requires less oxygen than is present in air. E) prefers to grow without oxygen. 19 The term obligate anaerobe refers to an organism that A) doesn't use oxygen but tolerates it. B) is killed by oxygen. C) uses oxygen when present or grows without oxygen when oxygen is absent. D) requires less oxygen than is present in air. E) prefers to grow without oxygen. 20 The term aerotolerant anaerobe refers to an organism that A) doesn't use oxygen but can grow in the presence oxygen. B) is killed by oxygen. C) uses oxygen when present or grows without oxygen when absent. D) requires less oxygen than is present in air. E) prefers to grow without oxygen. 21 A microbiology student noticed that a Fluid Thioglycollate culture broth tube was very turbid at the surface and turbid throughout the rest of the tube. She can conclude that the A) broth is sterile. B) organisms cannot tolerate oxygen. C) organisms are aerobes. D) organisms should be put in a candle jar. E) organisms are facultative anaerobes. 22 A microbiology student noticed that a culture broth tube was very turbid at the surface but clear throughout the rest of the tube. She can conclude that the A) organism are aerobes. B) organism should be grown in an anaerobic chamber. C) organism cannot produce superoxide dismutase and/or catalase. D) organism cannot tolerate oxygen. E) broth is sterile. 23 A microbiology student noticed that a culture broth tube was very turbid at the bottom of the tube but clear at the top of the tube. She can conclude that the A) broth is sterile. B) organism can tolerate oxygen. C) organism cannot produce superoxide dismutase and/or catalase. D) organism should be grown in an anaerobic chamber. E) organism are aerobes. 24 Postgates assay technique is useful in determining if a cell is viable even though it is A) incapable of cell division. B) too small to see. C) killed by naturally occurring antibiotics in soil. D) an obligate aerobe. E) a thermophile.

Compare the following entities (I and II).

 25 I. average size of cells during the exponential phase of growthII. average size of cells during the lag phase of growth A) I is greater than II, mark A B) I is less than II, mark B C) I is exactly or approximately equal to II, mark C D) I may stand in more than one of the above relations to II, mark D 26 I. generation time of cells during the exponential phase of growthII. generation time of cells during the lag phase of growth A) I is greater than II, mark A B) I is less than II, mark B C) I is exactly or approximately equal to II, mark C D) I may stand in more than one of the above relations to II, mark D 27 I. generation time of a culture that produces 2 generations per hourII. generation time of a culture that produces 3 generations per hour A) I is greater than II, mark A B) I is less than II, mark B C) I is exactly or approximately equal to II, mark C D) I may stand in more than one of the above relations to II, mark D 28 I. number of viable cells detected in a culture using an electronic counting deviseII. number of viable cells detected in the same culture using a dilution and spread plating procedures A) I is greater than II, mark A B) I is less than II, mark B C) I is exactly or approximately equal to II, mark C D) I may stand in more than one of the above relations to II, mark D 29 The total biomass of an organism will be determined by the nutrient present in the lowest concentration relative to the organism's requirements is a statement of A) Liebig's Law of the minimum. B) Shelford's law of tolerance. C) the second law of thermodynamics. D) quorum sensing. E) Heisenberg's principle of uncertainty. 30 The ability of Vibrio fischeri to produce bioluminescence chemicals only when a certain population density has been reached is an example of A) Liebig's Law of the minimum. B) Shelford's law of tolerance. C) the second law of thermodynamics. D) quorum sensing. E) Heisenberg's principle of uncertainty.