Test Practice Questions to Study for Microbiology

Test Bank Key Multiple Choice Questions 1. A microbiologist inoculates Staphylococcus aureus into a culture medium. Following incubation, both Staphylococcus aureus and Staphylococcus epidermidis are determined to be growing in this culture. What is the most likely explanation? A. B. C. D. E. 2. A microbiologist inoculates Staphylococcus epidermidis and Escherichia coli into a culture medium. Following incubation, only the E. coli grows in the culture. What is the most likely explanation? A. B. C. D. E. 3. The culture medium was selective. The culture medium was differential. The microbiologist used too much inoculum. The culture was contaminated. The incubation temperature was incorrect. Robert Koch and his colleagues first used agar in bacteriological media. Why was this ingredient an improvement on previous materials used to culture bacteria? A. B. C. D. 4. The microbiologist used too much inoculum. The culture medium was selective. The culture medium was differential. The culture was contaminated. The incubation temperature was incorrect. Agar can convert from liquid to solid form, and back again, very easily. Agar is a complete source of nutrients for most bacteria. Bacteria growing on the solidified medium did not degrade or break down the agar. Agar was less expensive than the nutrients that Koch was previously using in the lab. The bacterium Neisseria gonorrhoeae causes the sexually-transmitted infection gonorrhea. Although it can be isolated from the vagina, there are numerous normal biota in that location as well. To generate a pure culture of this pathogenic bacterium, the best choice is a(n) ______. A. B. C. D. differential medium enrichment medium selective medium liquid medium 5. Thioglycolate medium contains the following: yeast extract, pancreatic digest of casein, glucose, L-cysteine, sodium chloride, sodium thioglycolate, and agar. It is considered a complex medium because A. B. C. D. 6. Humans can see objects as small as 0.1 mm. Leeuwenhoek's best microscope could magnify objects to 300X. Which of the following would be invisible using Leeuwenhoek's microscope? A. B. C. D. 7. depending on their oxygen utilization pattern, organisms will grow differently on it. it has multiple ingredients for a broad range of nutrients. both yeast extract and pancreatic digest of casein are not chemically defined. thioglycolate has a carbon-sulfur bond that many microbes cannot break enzymatically. Poliovirus, 30 nm Red blood cell, 8 m Escherichia coli, 1 m X 4 m Pandora virus, 0.5 mm X 1 mm Cells of Staphylococcus aureus are cocci measuring about 1 m in diameter. In a textbook image of S. aureus, each cell measures about 1 cm. The magnification of the image on the page is ______. A. B. C. D. E. F. G. 10,000X 1,000X 100X 0.01X 0.001X 0.0001X This is impossible to calculate without more information. ASM Objective: 02.01 The structure and function of microorganisms have been revealed by the use of microscopy (including bright field, 8. Table 3.6 in your textbook uses Paramecium to illustrate several types of light microscopy. Each image is magnified 230X and measures about 4 cm. The actual size of a Paramecium is about ______. A. B. C. D. E. 920 m 0.2 m 175 m 57.5 m 4,000 m 9. Your microscope has a resolving power of 0.15 m. The specimen that you will be observing has bacterial cocci the size of 0.1 m in diameter. Which of the following statements is correct? A. B. C. D. 10. A microbiology student with a visual disability is viewing a sample of Bacillus endospores in a phase contrast microscope that is linked to an iPad. By "stretching" the image on the iPad screen, the student can increase the apparent size of the endospores. How does this manipulation affect resolution and contrast? (No software is being used to alter the image!) A. B. C. D. 11. Only the magnification can be increased; resolution and contrast are unchanged. Contrast will improve because the microscope is phase-contrast. Both magnification and resolution increase; contrast is unchanged. Resolution and magnification will decrease because the screen is not as good as the human eye. Agar is an important component of media because A. B. C. D. 12. The cocci will appear much smaller than their actual size because of the low resolution. The cocci will be fuzzy-looking and blend together. The cocci will not be visible. The cocci will be readily visible and distinct. agar provides a solid surface for bacterial growth. bacteria require agar as a source of carbon. agar inhibits mold growth. agar prevents contamination. The Five I's of studying microorganisms include all of the following except ______. A. B. C. D. E. identification isolation incubation infection inoculation 13. The term that refers to the purposeful addition of microorganisms into a laboratory nutrient medium is ______. A. B. C. D. E. 14. inoculation contamination infection immunization isolation A pure culture contains A. only bacteria. B. only one identified species of microorganism. C. a variety of species from the same genus. D. microbes from a single source. 15. The correct microbiological term for the sample of specimen that is put into a nutrient medium to produce a culture is ______. A. B. C. D. 16. loop inoculum streak colony Which isolation technique is most effective for the majority of applications and is most commonly used for colony isolation in the laboratory? A. B. C. D. E. Spread plate Streak plate Pour plate Culture plate Loop dilution 17. Which of the following is not an inoculating tool? A. B. C. D. E. 18. What is the term for a culture made from one isolated colony? A. B. C. D. E. 19. Pipette Swab Petri dish Loop Needle Axenic Mixed Pure Both axenic and mixed are correct. Both axenic and pure are correct. Newly inoculated cultures must be _____ at a specific temperature and time to encourage growth. A. B. C. D. incubated streaked spread poured True / False Questions 20. The procedures for culturing a microorganism require the use of a microscope. FALSE 21. Some microbes are not capable of growing on artificial media as pure cultures. TRUE 22. Mixed cultures are also referred to as contaminated cultures. FALSE 23. Bacterial cultures are easily identified from their microscopic appearance. FALSE Multiple Choice Questions 24. Which method often results in colonies developing down throughout the agar along with some colonies on the surface? A. B. C. D. 25. Spread plate Pour plate Replica plate Streak plate All of the following are examples of different types of microbiological media except ______. A. B. C. D. E. agar enriched broth Petri dish semisolid 26. Which of the following is essential for the development of discrete, isolated colonies? A. B. C. D. E. 27. Which of the following is produced by adding 1% to 5% agar to nutrient broth that is then boiled and cooled? A. B. C. D. E. 28. solid, semisolid, and liquid reducing, transport, and enumeration a streak plate, a pour plate, and a broth solid, liquid, and gas Agar is a complex polysaccharide that comes from a/an ______. A. B. C. D. E. 30. A pure culture A contaminated medium A liquid medium A mixed culture A solid medium The three physical forms of laboratory media are ______. A. B. C. D. 29. Solid medium Differential medium Broth medium Assay medium Selective medium bacterium algae fungus marine invertebrate green plant Which of the following is not a benefit of agar as a solid medium? A. Holds moisture B. C. D. E. Flexibility Solid at room temperature Can be inoculated and poured at a temperature that is not harmful Easily digested by most microbes True / False Questions 31. A medium that is gel-like has less agar in it compared to a solid medium. TRUE Multiple Choice Questions 32. Which type of medium would be the best choice when shipping a sample of bacteria from a clinic to a laboratory for testing? A. B. C. D. 33. A common medium for culturing fastidious bacteria is ______. A. B. C. D. E. 34. Thioglycolate medium Eosin-methylene blue agar Transport medium Blood agar trypticase soy agar reducing medium mannitol salt agar blood agar MacConkey medium A reducing medium contains A. B. C. D. E. sugars that can be fermented. extra oxygen. hemoglobin, vitamins, or other growth factors. substances that remove oxygen. inhibiting agents. 35. Which type of medium distinguishes different types of microorganisms based on an observable change in the colonies or in the medium? A. B. C. D. E. 36. Differential media result in which of the following observable characteristics? A. B. C. D. E. 37. Differently colored colonies Different media color after incubation Chemical precipitates Gas bubbles All of the choices are correct. A reducing medium is used to culture ______ organisms. A. B. C. D. 38. Enriched Enumeration Selective Reducing Differential fastidious pathogenic anaerobic aerobic Mannitol salt agar is selective for organisms in which bacterial genus? A. B. C. D. E. Salmonella Staphylococcus Escherichia Neisseria Streptococcus 39. A microbiologist must culture a patient's feces for intestinal pathogens. Which of the following components would likely be present in a selective medium for this purpose? A. B. C. D. E. 40. Thioglycolic acid Sheep red blood cells Bile salts Peptone NaCl Bacteria that require special growth factors and complex nutrients are termed ______. A. B. C. D. E. fermentative hemolytic fastidious aerobic anaerobic True / False Questions 41. A selective medium contains one or more substances that inhibit growth of some microbes to facilitate the growth of other desired microbes. TRUE Multiple Choice Questions 42. Eosin-methylene blue agar, or EMB, is a commonly used bacteriological medium for growing gramnegative bacteria from complex environments. It contains two dyes, eosin and methylene blue, as well as the sugar lactose. Eosin is a pH indicator that changes color when the medium is acidic, while methylene blue inhibits the growth of most gram-positive bacteria. If an organism consumes lactose, acid will be produced, causing the bacterial colonies to change color. Based upon this description, this medium is ______. A. reducing B. for enrichment C. selective D. differential and selective E. differential 43. A nutrient medium that has all of its chemical components identified and their precise concentrations known and reproducible is termed ______. A. B. C. D. 44. A nutrient medium that contains at least one ingredient that is not chemically defined is termed ______. A. B. C. D. 45. enriched complex reducing synthetic All of the following are diameters of cells that would be resolved in a microscope with a limit of resolution of 0.2 µm except ______. A. B. C. D. 46. reducing enriched complex defined 0.2 mm 0.1 µm 2.0 µm 0.2 µm Who invented the first crude microscope by grinding glass? A. B. C. D. E. Lister Schultz and Schwann Leeuwenhoek Redi Pasteur 47. The simple microscopes used by the earliest practitioners of microscopy contained which of the following? A. B. C. D. E. 48. The _____ of the microscope holds and allows selection of the objective lenses. A. B. C. D. 49. Body Condenser Objective lens Ocular lens Nosepiece Which of the following parts of the microscope magnifies the specimen to produce the virtual image of the specimen? A. B. C. D. 51. ocular condenser stage nosepiece Which of the following parts of a microscope magnifies the specimen to produce a real image of the specimen? A. B. C. D. E. 50. Magnifying lens Oil-immersion lens Lamp Ocular Condenser Ocular lens Objective lens Condenser Body If a microbiologist is studying a specimen at a total magnification of 950X, what is the magnifying power of the objective lens if the ocular lens is 10X? A. 95X B. 940X C. 950X D. 9500X 52. Magnification is achieved in a compound microscope through the initial magnification of the specimen by the _____ lens. This image is then projected to the _____ lens that will further magnify the specimen to form a virtual image received by the eye. A. B. C. D. 53. Which term refers to the microscope's ability to show two separate objects as discrete and distinct? A. B. C. D. 54. Contrast Magnification Refraction Resolution The wavelength of light used and the numerical aperture governs ______. A. B. C. D. E. 55. ocular; oil immersion scanning; objective ocular; objective objective; ocular resolution contrast illumination size of the field magnification Scattering of peripheral light rays through the glass slide under very high magnification can be prevented by ______. A. B. C. D. the condenser the ocular immersion oil the cover slip 56. The type of microscopy in which you would observe brightly illuminated specimens against a black background is ______. A. B. C. D. E. 57. Which type of microscopy transforms the subtle variations in cell density into differences in light intensity, allowing for increased internal detail without staining? A. B. C. D. E. 58. Confocal Electron Bright-field Fluorescence Phase-contrast All of the following pertain to the fluorescence microscope except A. B. C. D. E. 60. Electron Fluorescence Bright-field Confocal Phase-contrast Which type of microscope shows cells against a white background? A. B. C. D. E. 59. dark-field confocal fluorescence phase-contrast electron it is a type of compound microscope. it is used to diagnose certain infections. it uses electrons to produce a specimen image. it requires the use of dyes like acridine or fluorescein. it requires an ultraviolet radiation source. A scanning confocal microscope A. B. C. D. produces specimen images on electron micrographs. uses dyes that emit visible light when excited by ultraviolet radiation. uses ultraviolet light to form a specimen image. scans narrow planes and can build a three-dimensional image of the specimen. 61. The specimen preparation technique that is best for viewing cell motility is the ______. A. B. C. D. E. flagellar stain Gram stain negative stain hanging drop fixed, stained smear True / False Questions 62. The bending of light rays as they pass from one medium to another is called refraction. TRUE 63. A differential interference contrast microscope uses dyes to give colored, three-dimensional images. FALSE Multiple Choice Questions 64. Which type of microscope does not use light in forming the specimen image? A. B. C. D. E. 65. Electron Dark-field Phase-contrast Bright-field Fluorescence Which type of microscope achieves the greatest resolution and highest magnification? A. B. C. D. E. Bright-field Fluorescence Electron Dark-field Phase-contrast 66. Which type of microscope cannot image live specimens? A. B. C. D. E. 67. Which type of microscope bombards a whole, metal-coated specimen with electrons moving back and forth over it? A. B. C. D. E. 68. Transmission EM is used for internal detail of cells and subcellular structures. Transmission EM gives detail of the external architecture of cells. Transmission EM requires dyes. Transmission EM can provide good images of bacteria but not viruses. The purpose of staining cells on a microscope slide is to ______. A. B. C. D. E. 70. Transmission electron Differential interference contrast Scanning electron Phase-contrast Fluorescence Comparing transmission electron microscopy with scanning electron microscopy, the following statement is true. A. B. C. D. 69. Differential interference Bright-field Electron Dark-field Phase-contrast secure them to the slide kill them observe motility enlarge the cells add contrast to see them better The Gram staining procedure is best described as a ______ staining technique. A. B. C. D. 71. negative simple selective differential What do the Gram stain, the acid-fast stain, and the endospore stain have in common? A. They use heat to force the dye into cell structures. B. The staining outcome varies with the charge of the cell wall. C. They are used on a wet mount of the specimen. D. They are differential stains. E. They use a negative stain technique. 72. Basic dyes are A. B. C. D. E. 73. repelled by cells. attracted to the acidic surface of bacterial cells. used in negative staining. dyes such as India ink and nigrosin. anionic. A microbiologist makes a fixed smear of bacterial cells and stains it with methylene blue. All cells appear blue under the oil immersion lens. This is an example of ______. A. B. C. D. E. simple staining negative staining capsule staining the acid-fast stain using an acidic dye True / False Questions 74. Fixed smears of specimens are required to perform the Gram stain or the endospore stain. TRUE 75. Following a properly-performed Gram stain, gram-positive bacteria will appear as pink or red cells. FALSE Test Bank Summary Categor y ASM Objective: 02.01 The structure and function of microorganisms have been revealed by the use of microscopy (in cluding bright field, phase contrast, fluorescent, and electron). ASM Objective: 06.03 Humans utilize and harness microorganisms and their products. ASM Objective: 08.01 Properly prepare and view specimens for examination using microscopy (bright field and, if po ssible, phase contrast). ASM Objective: 08.02 Use pure culture and selective techniques to enrich for and isolate microorganisms. # of Questions 3 1 33 36 ASM Objective: 08.03 Use appropriate methods to identify microorganisms (mediabased, molecular and serological). 10 ASM Objective: 08.05 Use appropriate microbiological and molecular lab equipment and methods. 2 ASM Topic: Module 02 Structure and Function 3 ASM Topic: Module 06 Impact of Microorganisms ASM Topic: Module 08 Microbiology Skills 1 72 Blooms Level: 1. Remember 37 Blooms Level: 2. Understand 25 Blooms Level: 3. Apply 8 Blooms Level: 4. Analyze 5 Learning Outcome: 03.01 Explain what the Five I's mean and what each step entails. Learning Outcome: 03.02 Discuss three physical states of media and when each is useful. Learning Outcome: 03.03 Compare and contrast selective and differential media, and give an example of each. 15 10 Learning Outcome: 03.04 Provide brief definitions for defined and complex media. 3 Learning Outcome: 03.05 Convert among different lengths within the metric system. 4 12 Learning Outcome: 03.06 Describe the earliest microscopes. 3 Learning Outcome: 03.07 List and describe the three elements of good microscopy. Learning Outcome: 03.08 Differentiate between the principles of light and electron microscopy. Learning Outcome: 03.09 Compare and contrast the three main categories of stains, and provide examples of each. 19 5 Section: 03.01 38 Section: 03.02 37 Topic: Culturing Microorganisms 37 Topic: Identifying Microorganisms Topic: Microscopy 3 28 Topic: Preparing Microscopy Specimens 9 7