Take-Home Quiz I. Please note that questions 1-25 cover material solely from Chapters 1 through 5.

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1 Take-Home Quiz I General Instructions and Information: Obtain an answer sheet from the instructor and legibly write your name in the appropriate space. After placing your name and quiz version on the answer sheet, you must enter your student number (social security number) in the appropriate space and darken the corresponding bubbled numbers. Should you not enter your student number or should you incorrectly darken the bubbles, five (5.0) points will be deducted from your final score for this quiz. In addition, be sure to place the instructor s last name on the lines provided. This Take-Home Quiz consists of fifty (50) questions. Half are multiple choice, whereas the other half consists of True/False statements. When answered correctly, each is worth one point (1) point. Please note that your answer sheet is due NO LATER than 10:00 AM, Monday, February 7th. Answer sheets returned later than this deadline will not be accepted and a score of 0 will be recorded. Note the following restrictions: You are permitted to collaborate on this quiz with other students who are currently enrolled in this course. However, you are not permitted to just copy answers from one another. You must make an honest effort to actively gather the answers by yourself or within a study group. The lack of a good faith effort on your part will be considered academic dishonesty. Also, receiving help from students not enrolled in this course or from sources other than those specifically associated with this course will be considered an act of academic dishonesty. Such incidents will not be tolerated and will be handled according to course and University policy. Instructions For Answering Multiple Choice Questions: Read each question very carefully. Determine the BEST answer for a particular question from among the four different choices listed below it. Darken the appropriate bubble on the answer sheet corresponding to the question you are answering. In doing so, be sure to follow the instructions on the back of the answer sheet. Mismarked answer sheets (i.e, answers placed out of order) will not be rescored. Hence, you are strongly encouraged to review your answer sheet before returning it. Please note that questions 1-25 cover material solely from Chapters 1 through Cells with a relatively complex morphology that have a true membrane-delimited nucleus are called A) prokaryotes. B) eucaryotes. C) urcaryotes. D) nocaryotes. Page 1 of 7

2 2. Cells with a relatively simple cell morphology that do not have a true membranedelimited nucleus are called A) prokaryotes. B) eucaryotes. C) urcaryotes. D) nocaryotes. 3. Who of the following provided the evidence needed to discredit the concept of spontaneous generation? A) Pasteur B) Koch C) Semmelweiss D) Lister 4. Who of the following developed a set of criteria that could be used to establish a causative link between a particular microorganism and a particular disease? A) Fracastoro B) Koch C) Pasteur D) Lister 5. In the Gram-staining procedure, the primary stain is A) iodine. B) safranin. C) crystal violet. D) alcohol. 6. If the decolorizer is not left on long enough in the Gram-staining procedure, grampositive organisms will be stained and gram-negative organisms will be stained. A) purple; purple B) purple; colorless C) purple; pink D) pink; pink 7. An instrument that magnifies slight differences in the refractive index of cell structures is called a(n) microscope. A) phase-contrast B) electron C) fluorescence D) densitometric Page 2 of 7

3 8. In the Gram-staining procedure, the mordant is A) iodine. B) safranin. C) crystal violet. D) alcohol. 9. The type II protein secretion pathway of bacteria A) plays a key role in directing proteins to the periplasm. B) is also known as the ABC protein secretion pathway and secreted proteins usually have a C-terminal secretion signal. C) directs secretion of some proteins from the periplasm across the outer membrane. D) functions by transporting flagellum proteins to their extracellular site of assembly. 10. Flexible bacteria with a helical shape are called A) vibrios. B) spirilla. C) spirochetes. D) coccobacilli. 11. Endospores represent a challenge to the fields of industrial and medical microbiology because A) they are resistant to harsh environments, thus allowing survival of spore forming organisms under conditions in which nonsporulating cells would not survive. B) spore forming organisms are often dangerous pathogens. C) spores are significantly smaller than vegetative cells. D) a and b are correct 12. Bacterial cells that are variable in shape are called A) vibrio. B) pleomorphic. C) coccobacilli. D) hyphal. 13. Which of the following is/are true of capsules? A) They help bacteria escape phagocytosis by host cells. B) They retain water and help prevent desiccation of the bacteria. C) They prevent entry of many bacterial viruses. D) all of the above Page 3 of 7

4 14. Protein filaments with a diameter of 4-7 nm that play a role in cell movement and shape change are called A) microtubules. B) microfilaments. C) intermediate filaments. D) mycelia. 15. The process by which a cell imports large particles by enclosing them in vesicles pinched off from the plasma membrane is called A) exocytosis. B) phagocytosis. C) pinocytosis. D) nutrient cytosis. 16. Which of the following organelles is involved in the modification, packaging, and secretion of materials? A) lysosomes B) Golgi apparatus C) mitochondria D) centrioles 17. The Golgi apparatus is responsible for the synthesis of A) ribosomes. B) lysosomes. C) mesosomes. D) nucleosomes. 18. The endoplasmic reticulum is composed of flattened sacs called A) thylakoids. B) cristae. C) cisternae. D) vacuomes. 19. The nucleolar organizer is a part of a specific chromosome that directs the synthesis of A) transfer RNA (trna). B) ribosomal RNA (rrna). C) messenger RNA (mrna). D) heterogeneous nuclear RNA (hnrna). Page 4 of 7

5 20. Elements that are required in relatively large amounts by microorganisms are called A) multivitamins. B) meganutrients. C) macronutrients. D) macromolecules. 21. Organisms that can use carbon dioxide as their sole or principal source of carbon are A) auxotrophs. B) autotrophs. C) prototrophs. D) heterotrophs. 22. The movement of molecules across a membrane from an area of higher concentration to an area of lower concentration with the use of a carrier molecule embedded in the membrane is called A) facilitated diffusion. B) osmosis. C) passive diffusion. D) active transport. 23. Organisms that obtain energy from the oxidation of either organic or inorganic compounds are called A) chemotrophs. B) lithotrophs. C) organotrophs. D) phototrophs. 24. Organisms that use reduced, preformed organic molecules as carbon sources are A) auxotrophs. B) autotrophs. C) prototrophs. D) heterotrophs. 25. A growth medium that distinguishes among different groups of bacteria on the basis of their biological characteristics is called a medium. A) selective B) differential C) enrichment D) transport Page 5 of 7

6 Instructions For Answering True/False Questions: Read each of the following True/False questions very carefully. Determine if the statement that you are reading, as written, is true or false. If you believe that the statement is true, then darken the A bubble on the answer sheet corresponding to the numbered statement you are answering. If you believe that the statement is false, then darken the B bubble on the answer sheet corresponding to the numbered statement you are answering. Mismarked answer sheets (i.e, answers placed out of order) will not be rescored. Hence, you are strongly encouraged to review your answer sheet before returning it. Please note that statements cover material solely from Chapters 6 through One of the major advantages of a continuous culture system is that the cells can be maintained in the exponential growth phase for extended periods of time. 27. In the process of photoreactivation, blue light provides energy to help repair of thymine dimers produced in DNA by ultraviolet radiation. 28. When a young, vigorously growing culture of bacteria is transferred to fresh medium of the same composition, the lag phase is usually short or absent. 29. When a young, vigorously growing culture of bacteria is transferred to fresh medium of different composition, the lag phase is usually short or absent. 30. Obligate anaerobes are usually poisoned by molecular oxygen but may grow in aerobic habitats if associated with facultative anaerobes that use up all available oxygen. 31. During the lag phase of microbial growth, the cells are metabolically inactive. 32. Membranes of some thermophilic Archaea are stabilized by lipids that span the membrane and form a rigid stable tetraether based monolayer. 33. Ultraviolet radiation is generally more harmful than ionizing radiation. 34. The rate growth of a given species of microorganism is dependent on the composition of the medium in which it is grown. 35. Water activity is inversely proportional to osmotic pressure. 36. DNA of thermophiles is stabilized by binding of special histone proteins. 37. Membranes of some thermophilic bacteria are stabilized by ether linked phospholipids. 38. Ultraviolet radiation is an effective means of sterilizing surfaces. Page 6 of 7

7 39. Germicides kill all pathogenic organisms and endospores. 40. Freezing at low temperature stops or greatly slows microbial growth due to DNA strand breakage. 41. Betapropiolactone is not as useful as ethylene oxide as a sterilizing agent because it does not penetrate materials as readily as ethylene oxide. 42. Microorganisms show differential sensitivity to antimicrobial agents. 43. Dry heat methods usually require lower temperatures and shorter exposure times than moist heat methods to achieve the same degree of killing because of the drying effects of this form of heat. 44. Alcohols are widely used as antiseptics and disinfectants because they are effective against endospores as well as vegetative cells. 45. The phenol coefficient is a direct indication of disinfectant potency during normal use. 46. Heavy metals may denature proteins by reacting with their sulfhydryl groups. 47. The rate of killing by an antimicrobial agent may slow when the microbial population has been greatly reduced because the remaining population may have a high proportion of resistant organisms. 48. Heavy metals are effective antimicrobial agents but are not widely used because of their high toxicity to humans. 49. Because filtration removes rather than destroys microorganisms, it does not truly sterilize the materials passing through the filter. 50. Larger populations generally are killed as rapidly as smaller populations. Page 7 of 7