Biology He suggested that mice could develop from spoiled grain by spontaneous generation.

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1 Biology 3340 Summer 2005 First Examination Version B Name Be sure to put your name on the mark-sense sheet as well Directions: Be sure to put your name on the mark-sense sheet and on the exam booklet. Both must be turned in at the end of the period. Indicate the correct version letter of your exam in the upper left corner of the mark-sense sheet in the box marked KEY ID. Each questions has only one correct answer. When a group of choices is used for more that one question, a choice may be used more than once. You may write in the exam booklet, but only the mark-sense sheet will be graded. No other paper, scratch paper, etc., may be used. Students must turn in the exam before leaving the room for any reason. A student may not continue working on the exam after having left the room. Multiple choice, 50 questions The following choices are used for questions 1 5. Redi Pasteur Tyndall Aristotle Leeuanhoek 1. He suggested that mice could develop from spoiled grain by spontaneous generation. 2. He performed experiments using media in swan necked flasks that permitted free exchange of air while preventing contaminating particles from entering the flask. In doing so, he countered the objections of Needham and demonstrated that microbes do not develop by spontaneous generation. 3. Using a single-lens microscope, he discovered the existence of microbes. 4. By filtering air before it entered a culture vessel containing media, he demonstrated that airborne microbial contamination came from microbes attached to dust particles in the air. 5. He demonstrated that maggots (fly larvae) developed from fly eggs, not spontaneous generation. Biology 3340/Summer 2005 Exam 1, Version B Page 1

2 The following choices are used for questions Pasteur Snow Koch Semmelweis Lister 6. He suggested that the incidence of infections in mothers after childbirth could be reduced if the attendants washed their hands before delivering the baby. 7. He developed antiseptic surgical procedures that used carbolic acid (phenol) as a disinfectant. 8. By using maps to localize the source of a cholera epidemic in London to a specific public water pump, he was able to reduce its spread by implementing public health measures. 9. He developed a vaccine for rabies. 10. Using colony isolation techniques on agar media, he isolated the anthrax and tuberculosis bacteria and demonstrated their roles in disease. The following choices are used for questions This property is found in both prokaryotic cells and eukaryotic cells. This property is found in prokaryotic cells. This property is found in eukaryotic cells. This property is found in viruses. 11. The ability to replicate by cell division. 12. Plasma membranes that contain specialized folds for the process of respiration. 13. A nucleus surrounded by a nuclear membrane. 14. Replication via a process of attachment and penetration of a host cell, disassembly, synthesis of protein and nucleic acid components, reassembly, and release from the host cell. 15. Particles containing either DNA or RNA, but not both. 16. Extensive internal membrane systems such as endoplasmic reticulum and Golgi apparatus. 17. Plasma membranes that serve as a selective transport barrier, separating the cytoplasm of the cell from the outside. Biology 3340/Summer 2005 Exam 1, Version B Page 2

3 18. Flagella that are composed of a flagellin-based filament and a hook-and-rotor assembly. 19. Read each of the following three statements about bacterial colonies. I. Ideally, an isolated bacterial colony contains cells of only a single species. II. The morphology of a bacterial colony is a characteristic of the species. III. Bacterial colonies can be isolated by streaking the bacteria onto a semisolid medium. Which statement(s) is (are) true? I and II only I only II and III only I, II, and III I and III only 20. Porins are proteins embedded in the outer membrane of gram-negative bacteria. are the organelles that assemble amino acids into proteins. are granules of glycogen found in the cytoplasm of certain bacteria. are regions of the bacterial plasma membrane that are rich in cholesterol. are plasma membrane folds found in certain bacteria. 21. Mesosomes are proteins embedded in the outer membrane of gram-negative bacteria. are the organelles that assemble amino acids into proteins. are granules of glycogen found in the cytoplasm of certain bacteria. are regions of the bacterial plasma membrane that are rich in cholesterol. are plasma membrane folds found in certain bacteria. 22. Which of the following best describes the structure of peptidoglycan? a polymer of glycerol or ribitol linked by phosphate groups a polymer of alternating glucosamine and ethanolamine units linked by ester bonds a polymer of β-hydroxybutyrate units linked by pentapeptide bridges a polymer of alternating N-acetylglucosamine and N-acetylmuramic acid units linked by glycosidic bonds a polymer of O chain polysaccharide and core polysaccharide attached to a Lipid A molecule Biology 3340/Summer 2005 Exam 1, Version B Page 3

4 23. Which of the following best describes the structure of teichoic acid? a polymer of glycerol or ribitol linked by phosphate groups a polymer of alternating glucosamine and ethanolamine units linked by ester bonds a polymer of β-hydroxybutyrate units linked by pentapeptide bridges a polymer of alternating N-acetylglucosamine and N-acetylmuramic acid units linked by glycosidic bonds a polymer of O chain polysaccharide and core polysaccharide attached to a Lipid A molecule 24. Adjacent chains of peptidoglycan may be covalently crosslinked by short chains of 4 or 5 lipopolysaccharide molecules. tetrapeptide chains that are directly connected to each other. tetrapeptide chains that are connected by a pentapeptide interbridge. both and both and 25. A peptidoglycan layer that is about 50 nm thick is commonly seen in mycoplasmas. gram-positive bacteria. gram-negative bacteria. archaeobacteria. acid-fast bacteria. 26. A periplasmic space that takes up 20% to 40% of the total cell volume is associated with mycoplasmas. gram-positive bacteria. gram-negative bacteria. archaeobacteria. acid-fast bacteria. 27. The O side chain antigen is a component of the outer membrane of the gram-negative cell wall. the hook-and-rotor assembly of a bacterial flagellum. the spore coat of a bacterial endospore. the inner leaflet of a bacterial plasma membrane. the photosynthetic electron transport chain of photosystem II. Biology 3340/Summer 2005 Exam 1, Version B Page 4

5 28. In bacteria that possess flagella, a change of direction in movement is accomplished when ions are pumped through porin protein channels, causing the electrical polarity of the cell surface to change from positive to negative. ions are pumped through porin protein channels, causing the electrical polarity of the cell surface to change from negative to positive. electrons are transported through a series of membrane proteins, causing an increase in the cytoplasmic concentration of ATP. the direction of the flagella s spin reverses, causing the cell to tumble and change its orientation in a random fashion. the rudder proteins of the flagellar basal body undergo a conformational change, altering the angle between the flagellar filament and the cell surface. 29. In positive chemotaxis, as a bacterial cell approaches an attractant the angle ζ between the flagellar filament and the cell surface increases. the angle ζ between the flagellar filament and the cell surface decreases. the lengths of the straight runs increase. the lengths of the straight runs decrease. the electrical charge at the cell surface becomes increasingly positive. The following choices are used for questions organotroph lithotroph heterotroph phototroph autotroph 30. This is the best term to describe an organism that can use light as an energy source. 31. This is the best term to describe an organism that can utilize CO2 as its sole carbon source. 32. This is the best term to describe an organism that uses an inorganic substance as its source of electrons or reduction potential. 33. How do the S strain and R strain of Streptococcus pneumoniae differ from each other? The strains belong to different genera. The strains belong to different species. Cells of the S strain are encapsulated and virulent, while cells of the R strain are not encapsulated and not virulent. Cells of the R strain are encapsulated and virulent, while cells of the S strain are not encapsulated and not virulent. More than one of the above choices is true. Biology 3340/Summer 2005 Exam 1, Version B Page 5

6 34. Metachromatic granules are composed of sulfur polysaccharide lipid protein phosphate The following choices are used for questions bacillus spirillum coryneform bacteria spirochete vibrio 35. This term designates bacteria that have irregular rod-shaped cells found in V- and L- shaped arrangements. 36. This term designates comma-shaped bacteria. The following choices are used for questions streptococcus diplococcus staphylococcus tetrad sarcina 37. This term designates spherical bacterial cells arranged in chains. 38. This term designates spherical bacterial cells arranged in pairs. 39. This term designates spherical bacterial cells arranged in cubical packets of eight cells. The following choices are used for questions semisolid medium selective medium chemically-defined medium complex medium differential medium 40. Which term best defines a medium that allows some bacteria to grow but inhibits the growth of others? 41. Which term best describes a medium for which the exact composition is known? Biology 3340/Summer 2005 Exam 1, Version B Page 6

7 The following information pertains to questions Thioglycolate broth is a differential medium used to determine the oxygen requirements of bacteria. When a test tube of thioglycolate broth is prepared, an oxygen gradient is established. This means that there is a high concentration of oxygen at the surface of the broth, less oxygen in the middle of the tube, and no oxygen at the bottom of the tube. The following choices are used for questions strict aerobe aerotolerant anaerobe strict anaerobe microaerophile facultative anaerobe 42. If cells of a bacterial species grow only at the surface of a thioglycolate broth tube, to which group does the species belong? 43. If cells of a bacterial species grow in one narrow band somewhere in the middle of the tube between the surface and the bottom of the tube, to which group does the species belong? (Note: the bacteria do not grow on the surface nor on the bottom, but in a narrow band in the middle.) 44. If cells of a bacterial species grow only at the bottom of a thioglycolate broth tube, to which group does the species belong? 45. Suppose that you wanted to determine the optimal growth temperature of a bacterial species. Which of the following experiments would be most appropriate? Measure the maximum optical absorbance at stationary phase of batch cultures grown at different temperatures. Measure the mean generation time during the logarithmic growth stage of batch cultures grown at different temperatures. Measure the duration of the lag phase of batch cultures grown at different temperatures. Measure the flow rate of the nutrient feed of continuous cultures grown at different temperatures. Measure the nutrient concentration in the nutrient feed of continuous cultures grown at different temperatures. Biology 3340/Summer 2005 Exam 1, Version B Page 7

8 The following choices are used for questions Continuous culture Batch culture Biofilm 46. A closed system in broth medium in which no additional nutrient is added after inoculation of the broth. 47. An open system in which fresh media is continuously added to the culture at a constant rate, and old broth is removed at the same rate. 48. Growth of microbes attached to surfaces (such as soil particles, teeth, etc.) 49. Of the following methods, which one would be most appropriate for determining the bacterial concentration in a drinking water sample (which should not be over two or three bacterial cells per 100 ml)? Direct microscopic count Serial dilution and spread plating Membrane filtration Turbidity measurement with a spectrophotometer Dry mass determination 50. Organisms that grow at elevated salt concentrations (for example, in 1 M NaCl) are called Psychrophiles Mesophiles Alkalophiles Halophiles Microaerophiles Biology 3340/Summer 2005 Exam 1, Version B Page 8