Chapter 1: An Invisible World * = Correct answer Multiple Choice
1. Which of the following is true of the microbial world? A. All microbes are harmful. B. Humans could survive without microbes. C. Many microbes are helpful.* D. Most microbes are pathogenic. Difficulty: Easy ASM Standard: 23, 24 2. Which of the following is when humans first suspected the existence of microbes? A. during the Industrial Revolution B. in prehistoric times* C. in the last century D. within the last 500 years Difficulty: Easy ASM Standard: 23 3. Which individual first observed unicellular organisms, which he called “animalcules,” using a microscope he developed? A. Robert Koch B. Louis Pasteur C. Thucydides D. Antonie van Leeuwenhoek* Difficulty: Easy ASM Standard: 6 4. To reduce the risk of open flame from Bunsen burners, microbiologists are increasingly using which of the following devices for easy, rapid benchtop sterilization of small pieces of equipment? A. autoclaves B. ethylene oxide C. incubators
D. microincinerators* Difficulty: Easy ASM Standard: 36
5. The Swedish botanist known for having developed an important biological classification system is which of the following people? A. Ernst Haeckel B. Carolus Linnaeus* C. Louis Pasteur D. Robert Whittaker Difficulty: Easy ASM Standard: N/A 6. Which kingdom was the only one found in Empire Prokaryota? A. Animalia B. Fungi C. Monera* D. Protista Difficulty: Easy ASM Standard: N/A 7. Which are the three currently accepted domains? A. Archaea, Bacteria, and Eukarya* B. Archaea, Prokaryota, and Eukaryota C. Bacteria, Fungi, and Protista D. Bacteria, Prokaryota, and Eukarya Difficulty: Easy ASM Standard: N/A 8. Which two taxonomic units are typically used to identify an organism when using binomial nomenclature? A. domain and kingdom B. genus and family C. genus and species* D. phylum and class Difficulty: Easy ASM Standard: N/A 9. Which of the following is not true about the process of fermentation? A. It can help preserve foods, preventing spoilage. B. It converts sugars to organic acids, alcohols, and/or gases such as carbon dioxide.
C. It is carried out exclusively by unicellular eukaryotes such as yeast.* D. It is used to make foods such as cheese and bread. Difficulty: Moderate ASM Standard: 11, 23, 26
10. The Romans may have reduced their risk of waterborne infectious diseases by using which of the following? A. a variety of pharmaceutical products B. aqueducts and a sewer system* C. prophylactic antibiotics D. quarantine of people with leprosy Difficulty: Moderate ASM Standard: 23 11. For which of the following is Thucydides known? A. developing an effective sewer system in ancient Greece, helping to reduce levels of disease in cities B. observing microbes, using a microscope, for the first time, even distinguishing between bacteria and fungi C. proposing that disease was caused by microorganisms D. realizing that people who had been infected by the Athenian plague had immunity to reinfection* Difficulty: Moderate ASM Standard: 23, 31 12. Ernst Haeckel proposed a classification system consisting of which of the following subgroups? A. five kingdoms B. four kingdoms* C. two domains and three kingdoms D. two domains and five kingdoms Difficulty: Moderate ASM Standard: N/A 13. Viruses not included in phylogenetic trees for which of the following reasons? A. It is too difficult to observe their characteristics. B. They are acellular and nonliving.* C. They do not have any genes, which prevents genetic analysis. D. They lack a nucleus. Difficulty: Moderate ASM Standard: 5 14. Which is the best description of the primary purpose of a phylogeny? A. Phylogenies show all the alterative names for each species. B. Phylogenies show all the common names for each species. C. Phylogenies show evolutionary relatedness between organisms.*
D. Phylogenies show interactions between species in a shared habitat. Difficulty: Moderate ASM Standard: 5 15. Current phylogenetic analyses include which of the following? A. information from a range of sources, including morphological, genetic, and biochemical data* B. information on visible similarities only C. information regarding how to classify organisms on the basis of external morphological characteristics and visible behaviors D. varied morphological and structural characteristics, with preference for leaving historical classifications to prevent confusion Difficulty: Moderate ASM Standard: 5 16. Diatoms are classified within which of the following domains? A. Archaea B. Bacteria C. Eukarya* D. Prokaryota Difficulty: Moderate ASM Standard: N/A 17. Horizontal gene transfer involves which of the following? A. any transfer of genes in a laboratory setting B. the transfer of genes from a virus to a bacterium or vice versa but not any other form of gene transfer C. the transfer of genes from one individual to another, including from one species to another, but not from parent to offspring* D. the transfer of genes from parent to offspring Difficulty: Moderate ASM Standard: 2, 4 18. Bacteria are generally identified to species by using which of the following? A. a combination of genetic, biochemical, and microscopic approaches* B. a combination of microscopic and physiological approaches, but not genetics C. primarily characteristics such as motility that can be visualized using microscopy D. primarily morphological characteristics of individual cells Difficulty: Moderate ASM Standard: 34, 36
19. For taxonomic classification of microbes, serological tests typically are used to do which of the following? A. determine complete genome sequences for microbes B. identify proteins on the basis of their reaction with specific antibodies* C. run analyses to identify whether particular genes are present D. visualize microbial external morphology Difficulty: Moderate ASM Standard: 34, 36 20. Which of the following is true of bacterial strains? A. They are closely related subtypes within a bacterial species that may or may not have similar properties.* B. They are informal bacterial groupings used for medical distinctions but not recognized for classification purposes. C. They are more distantly related to each other than are members of a single bacterial species. D. They are very similar bacteria with almost identical properties. Difficulty: Moderate ASM Standard: 5 21. Bergey’s Manual of Systematic Bacteriology is used primarily as which of the following?
A. a guide to bacterial shapes B. a historical account of changes in classification techniques C. a list and characterization of all known medically relevant microbes D. a reference for bacterial classification* Difficulty: Moderate ASM Standard: 34 22. Which of the following indicates how bacteria and viruses typically compare in size? A. Bacteria are indistinguishable from viruses. B. Bacteria are much larger than viruses.* C. Bacteria are much smaller than viruses. D. Bacteria are similar in size to viruses. Difficulty: Easy ASM Standard: N/A 23. Viruses are classified as which of the following? A. Archaea B. Bacteria C. Eukarya D. distinct from the three-domain system*
Difficulty: Moderate ASM Standard: 4 24. Which of the following is not a curved bacterial shape? A. bacillus* B. spirillum C. spirochete D. vibrio Difficulty: Easy ASM Standard: 34 25. Based just on the name, which of the following groups of bacteria contains entirely species that consume organic compounds for food? A. cyanobacteria B. green nonsulfur bacteria C. green sulfur bacteria D. nonphotosynthetic bacteria* Difficulty: Moderate ASM Standard: 11, 13, 20 26. Chitin cell walls are characteristic of which taxonomic group? A. algae B. archaea C. bacteria D. fungi* Difficulty: Moderate ASM Standard: 20 27. Yeasts are which of the following? A. a type of algae B. a type of protist C. any unicellular microbe D. unicellular fungi* Difficulty: Moderate ASM Standard: 20 28. The cell walls of archaeans often contain which of the following substances? A. cellulose B. chitin C. peptidoglycan D. pseudopeptidoglycan*
Difficulty: Moderate ASM Standard: 20 29. Which of the following is not true of archaeans? A. Some species live on the human body. B. They are genetically distinct from bacteria. C. They are only found in extreme environments.* D. They have substantial metabolic differences from bacteria. Difficulty: Difficult ASM Standard: 20 30. Which of the following is not true of algae? A. All the algae are classified together in one similar group closely related to green plants.*
B. Ingredients made from algae, including carrageenan, are used in food products. C. They are being used to develop biofuels. D. They are sometimes multicellular. Difficulty: Moderate ASM Standard: 20, 23, 26 31. Oral thrush is caused by which type of organism? A. algae B. bacteria C. fungi* D. protists
Difficulty: Moderate ASM Standard: 23 32. Mycotoxins are produced by which type of organism? A. archaeans B. heterotrophic protists C. molds* D. protozoans Difficulty: Moderate ASM Standard: 23 33. Which of the following is not a common use of fungi? A. the production of alcoholic beverages B. the production of carrageenan* C. the production of cyclosporine D. the production of penicillin
Difficulty: Moderate ASM Standard: 20, 23, 26 34. The guinea worm is best described as which of the following? A. a helminthic parasite transmitted by consuming contaminated water* B. a type of mold that grows into a worm-like shape and produces antimicrobial chemicals
C. a type of protist found in water that has not been properly treated D. a type of protozoan that is unusual because it is multicellular Difficulty: Moderate ASM Standard: 23 35. Which of the following is true of the genetics of viruses? A. Viruses always contain DNA and force host cells to produce RNA. B. Viruses always contain DNA and RNA. C. Viruses always contain RNA and force host cells to produce DNA. D. Viruses can contain either DNA or RNA, but not both.* Difficulty: Moderate ASM Standard: N/A True/False 36. All organisms studied in the field of microbiology are visible only with a microscope. Answer: False Difficulty: Easy ASM Standard: N/A 37. Older scientific names are typically derived from Latin. Answer: True Difficulty: Easy ASM Standard: N/A 38. Animal cells are generally about the same size as bacterial cells. Answer: False Difficulty: Easy ASM Standard: N/A 39. Researchers studying a 5300-year-old mummy discovered in the 1990s think he may have been trying to use a fungus to treat his illnesses. Answer: True Difficulty: Easy
ASM Standard: 23, 26 40. Analyses of rRNA genes suggest that Archaea, Bacteria, and Eukarya evolved from a common ancestor. Answer: True Difficulty: Moderate ASM Standard: 5 41. The average size of a typical virus is approximately 100 nm. Answer: True Difficulty: Moderate ASM Standard: N/A 42. When a scientific name is used repeatedly, both the genus and species must always be written out in full to avoid confusion. Answer: False Difficulty: Moderate ASM Standard: N/A 43. Taenia saginata is a type of fungus that causes disease. Answer: False Difficulty: Moderate ASM Standard: 23 Matching 44. Match each type of microbiological tool with the best definition. A. loop i. tool used to transfer microbes from one location to another B. media ii. liquid, solid, or gel that contains nutrients to aid microbial growth C. microincinerator iii. tool used to sterilize equipment D. Petri plate iv. container used to grow microbial cultures Answers: A. i., B. ii., C. iii., D. iv. Difficulty: Easy ASM Standard: 36 45. Match the bacterial shape with the illustration.
(credit micrograph “i”: modification of work by Janice Haney Carr, Centers for Disease Control and Prevention; credit micrograph “iii”: modif ication of work by Centers f or Disease Control and Prevention)
Answers: A. v., B. i., C. iv., D. iii., E. ii. Difficulty: Easy ASM Standard: 34 46. Match each type of microbe with the best description. A. algae i. a very broad, informal grouping of organisms that do not fit into other eukaryotic kingdoms and that may be photosynthetic or nonphotosynthetic B. fungi ii. a diverse, informal subgroup of organisms that may move using cilia, flagella, or pseudopodia C. protists iii. a group of photosynthetic organisms with cellulose cell walls D. protozoa iv. a group of nonphotosynthetic organisms that usually have cell walls containing chitin Answers: A. iii., B. iv., C. i., D. ii. Difficulty: Moderate ASM Standard: 2 47. Match each subfield of microbiology with the most appropriate example. A. bacteriology i. the study of how antibodies are released in response to a pathogen B. immunology ii. the study of how fungi cause disease in plants C. mycology iii. the study of the classification of bacilli D. parasitology iv. the study of how to reduce the rate of guinea worm infections E. protozoology v. the study of heterotrophic protists
Answers: A. iii., B. i., C. ii., D. iv., E. v. Difficulty: Moderate ASM Standard: 23 48. Match each taxonomic group with its domain. You will use some options more than once.
A. algae i. Archaea B. halophiles ii. Bacteria C. helminths iii. Eukarya D. spirochetes Answers: A. iii., B. i., C. iii., D. ii. Difficulty: Moderate ASM Standard: 2 49. Match each causative agent with the associated classification. A. Dracunculus medinensis i. protist B. Ebola ii. fungus C. Giardia lamblia iii. helminth D. yeast iv. virus Answers: A. iii., B. iv., C. i., D. ii. Difficulty: Difficult ASM Standard: 23 Fill in the Blank 50.
was a Greek physician who posited that natural causes, not supernatural forces, caused disease. Answer: Hippocrates Difficulty: Easy ASM Standard: 23
51.
is the science of identifying, naming, and classifying living organisms. Answer: Taxonomy Difficulty: Easy ASM Standard: N/A
52. Fermentation by yeast produces ethanol and gas. Answer: carbon dioxide Difficulty: Moderate ASM Standard: 11, 26
53. Carl Woese and George Fox sequenced and analyzed wide range of organisms to build their phylogenetic tree. Answer: rRNA (or ribosomal RNA)
from a
Difficulty: Moderate ASM Standard: 4, 5 54. The archaebacteria are now called . Answer: Archaea Difficulty: Moderate ASM Standard: N/A 55. The genus of Halobacterium salinarum is . Answer: Halobacterium Difficulty: Easy ASM Standard: N/A 56. is the standard reference book that provides guidance onidentifying and classifying prokaryotes. Answer: Bergey’s Manual of Determinative Bacteriology Difficulty: Moderate ASM Standard: 34 57. There are nanometers in 520 meters. Answer: 520,000,000,000 Difficulty: Moderate ASM Standard: 29 58. The thermophilic genus Thermoproteus includes extremophiles classified in the domain . Answer: Archaea
Difficulty: Difficult ASM Standard: 5 59. The cytoplasmic extensions used by some protists to move are called . Answer: pseudopods Difficulty: Moderate ASM Standard: N/A Short Answer
60. What is horizontal gene transfer? Sample Answer: Horizontal gene transfer is the transfer of genetic material between two organisms that are not related as parent and offspring. Difficulty: Easy ASM Standard: 2 61. How are newly discovered organisms named? Sample Answer: Newly discovered organisms are usually given names that describe their characteristics and/or that honor a particular individual. The names are generally Latin, Greek, or English. Difficulty: Easy ASM Standard: 5 62. How do protozoa move? Sample Answer: Protozoa can move using structures such as pseudopods, flagella, and cilia. They may also be carried by the water in which they live. Difficulty: Easy ASM Standard: N/A 63. Why are formal scientific names based on a standardized system more useful than simple names that just describe characteristics, such as “orange cat-like animal”? Sample Answer: Organisms may have similar characteristics, especially in closely related species. By having a formal naming system, it is possible to clearly distinguish organisms so that people around the world can identify exactly which organism is being discussed.
Difficulty: Moderate ASM Standard: N/A 64. What are at least four types of products made using fermentation? Sample Answer: Fermentation is used to make alcoholic products, cheese, yogurts, pickled vegetables, and bread. Difficulty: Easy ASM Standard: 11, 23, 26 65. What is the Hippocratic Oath? Sample Answer: The Hippocratic Oath is an oath taken by new doctors to pledge their willingness to follow certain ethical guidelines, such as avoiding causing harm to their patients. Difficulty: Moderate ASM Standard: N/A31
66. Which famous scientist developed a vaccine for rabies? Sample Answer: Louis Pasteur developed a vaccine for rabies.
Difficulty: Moderate ASM Standard: 14, 23 67. Why is most milk pasteurized before it is sold? Sample Answer: Pasteurization helps reduce the number of microbes associated with spoilage and disease, keeping milk safe to drink longer than if it is not pasteurized.
Difficulty: Moderate ASM Standard: 14, 23 68. What are helminths and why are they medically important? Sample Answer: Helminths are worms. They are eukaryotes. They can be human parasites.
Difficulty: Moderate ASM Standard: 14, 23 69. Why is it often preferable to use a microincinerator rather than a Bunsen burner? Sample Answer: Bunsen burners have an open flame, whereas microincinerators do not; therefore, it is safer to use a microincinerator. Difficulty: Moderate ASM Standard: 14, 36 70. How do scientists decide how to organize organisms in a phylogenetic tree? Sample Answer: Phylogenies show evolutionary relationships. To develop a phylogenetic tree, scientists examine a variety of characteristics, including biochemical, morphological, and genetic characteristics, to determine the most likely relationships between organisms. Genetic data are especially important in determining these relationships in modern phylogenetic trees. Difficulty: Moderate ASM Standard: 5 71. What is the difference in how DNA is stored within the cells of prokaryotes versus eukaryotes? Sample Answer: Eukaryotes have a true membrane-bound nucleus and prokaryotes do not.
Difficulty: Moderate ASM Standard: 9
72. What does it m ean to say that som e photosynthetic bacteria, including som e green sulfur bacteria, are anoxygenic? Consider the word parts in “anoxygenic” if you are not sure. Sample Answer: Anoxygenic means that they do not generate oxygen.
Difficulty: Difficult ASM Standard: 11 73. Who published Systema Naturae and what did it present? Sample Answer: Systema Naturae was published by Carolus Linnaeus to present his taxonomic system. Difficulty: Difficult ASM Standard: N/A 74. Of the three domains, which is/are known to contain some human pathogens? Sample Answer: Bacteria and Eukarya contain some species that are human pathogens. No known archaeal pathogens have been identified. Difficulty: Moderate ASM Standard: 23 Brief Essay Essay Question Rubric RATING Failing Criteria for evaluati on
Answer does not provide an argument. Answer contains inaccuracies. Writing is poor and contains numerous grammatical mistakes and misspellings.
Below Average Answer fails to provide examples to support an argument. Writing is poor and grammatical errors are common. Answer is somewhat incoherent.
Competent
Advanced
Answer provides an argument with one or two examples that support it. Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.
Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently. Answer is well organized and free of grammatical errors and misspellings. 3
0 1 2 POINT VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.
75. Explain why some scientists think that it may be more appropriate to describe a “web of life” instead of a “tree of life.” Answer: Student answers will vary but should include components of the following. A tree suggests straightforward pathways of evolution from one branch to another. Because horizontal gene transfer is common, this does not fully represent the complexity involved in evolution. A web would better show ways genes can be transferred from one taxonomic group to another. Difficulty: Moderate ASM Standard: 5 76. Halobacterium salinarum is classified in the domain Archaea. Why does its name suggest it is a bacterium? This answer is not in the textbook chapter, so you should speculate based on your understanding of taxonomy. Answer: Student answers will vary but should include the following. This species was identified before the domain Archaea was recognized. As a result, it was previously considered a bacterium and given a bacterial name. Difficulty: Moderate ASM Standard: N/A 77. Consider the phylogenetic tree below. Explain how it shows the relationships between Bacteria, Archaea, and Eukarya, and their common ancestor. Of these three groups, which two are more closely related and how can you tell from the figure?
(credit: modification of work by Eric Gaba) Answer: Student answers will vary but should include the following. The lines leading to Bacteria, Archaea, and Eukarya branch from the same root, meaning they all share a common ancestor. Archaea and Eukarya branch more closely together than either branches with
Bacteria, suggesting that they diverged from each other more recently than they diverged from a common ancestor that had previously branched from Bacteria.
Difficulty: Difficult ASM Standard: 5 78. In the textbook chapter, there is information about efforts to eradicate the guinea worm. What are some factors that have allowed these efforts to be relatively successful, with only 126 cases reported in 2014, compared with efforts to eradicate other diseases such as hantavirus, carried by rodents, and rabies, carried by a variety of wild animals?
Answer: Student answers will vary but should include components of the following. Guinea worm is transmitted in contaminated water. Thus, efforts to improve water sanitation can be very effective in reducing infections. Other diseases have different mechanisms of transmission. Diseases such as rabies are found in wild animals and it would be difficult to treat or vaccinate all infected animals. Difficulty: Difficult ASM Standard: 14, 23, 31
This file is copyright 2017, Rice University. All rights reserved.
Chapter 2: How We See the Invisible World * = Correct answer Multiple Choice 1. Which term is used to refer to a wave’s rate of vibration? A. amplitude B. frequency* C. trough D. wavelength Difficulty: Easy ASM Standard: N/A 2. On the figure, which letter represents a refracted ray of light?
A. A B. B C. C D. D* Difficulty: Easy ASM Standard: N/A 3. On the electromagnetic spectrum, which type of wave has the shortest wavelength? A. cosmic ray* B. infrared ray C. ultraviolet ray D. visible light Difficulty: Moderate ASM Standard: N/A 4. Dyes are often used during microscopy to increase which of the following? A. contrast* B. magnification
C. motility D. resolution Difficulty: Easy ASM Standard: 32 5. Which of the following was the first to use the term “cells”? A. Robert Hooke* B. Robert Koch C. Carolus Linnaeus D. Antonie van Leeuwenhoek Difficulty: Easy ASM Standard: N/A 6. Which of the following is the typical magnification of an object viewed using a 10× ocular lens and a 100× objective lens on a brightfield microscope? A. 1× B. 10× C. 100× D. 1000×* Difficulty: Moderate ASM Standard: 32 7. Most modern microscopes have two eyepieces, meaning that they are which of the following? A. binocular* B. monocular C. oil immersion D. trinocular Difficulty: Easy ASM Standard: 32 8. An annular stop is used for which type of microscopy? A. confocal B. darkfield C. fluorescence D. phase contrast* Difficulty: Easy ASM Standard: 32 9. Which of the following is the specific name for a stain that colors the background but not the specimen?
A. acid-fast stain B. counterstain C. differential stain D. negative stain* Difficulty: Easy ASM Standard: 32 10. Which type of microscopy would work best for viewing internal cell structures? A. atomic force microscopy B. scanning electron microscopy C. scanning tunneling microscopy D. transmission electron microscopy* Difficulty: Moderate ASM Standard: 32 11. The Gram-staining procedure is best described as which of the following? A. complex staining B. differential staining* C. negative staining D. simple staining Difficulty: Easy ASM Standard: 32 12. When there is a substantial difference in refractive index between two materials, which of the following describes what will happen to light passing from one material to the other? A. It will fail to be refracted. B. It will undergo a large amount of refraction.* C. It will undergo a small amount of refraction. D. It will undergo a variable amount of refraction. Difficulty: Moderate ASM Standard: N/A 13. In microscopy, the focal length refers to which of the following? A. a description of the wavelength needed for an image to be in focus B. a measure of the amount of refraction produced by a lens C. a measure of the thickness of the lens needed for an image to be in focus D. the distance to the image point (at which all light entering a lens is parallel)* Difficulty: Moderate ASM Standard: 32 14. Which of the following are pigments used in microscopy to absorb and reflect light? A. chromatographs
B. chromophores* C. oilophores D. photophores Difficulty: Easy ASM Standard: N/A 15. Negative staining is the standard approach used to visualize which structure(s)? A. capsules* B. endospores C. flagella D. nucleoid regions Difficulty: Moderate ASM Standard: 6, 32 16. Which is a standard mordant used in flagella staining? A. basic fuchsin B. iodine C. safranin D. tannic acid* Difficulty: Moderate ASM Standard: 6, 32 17. Which of the following pairs are common acid-fast staining techniques? A. Gram and Kinyoun B. negative and Schaeffer-Fulton C. Ziehl-Neelsen and Kinyoun* D. Ziehl-Neelsen and Schaeffer-Fulton Difficulty: Moderate ASM Standard: 32 18. Which is the primary stain used in the Ziehl-Neelsen technique? A. acid-alcohol B. carbolfuchsin* C. crystal violet D. methylene blue Difficulty: Moderate ASM Standard: 32 19. Which is the correct order of steps in Gram staining? A. crystal violet stain, ethanol decolorization, Gram’s iodine mordant, safranin counterstain B. crystal violet stain, Gram’s iodine mordant, ethanol decolorization, safranin counterstain*
C. ethanol stain, crystal violet rinse, safranin counterstain, Gram’s iodine mordant D. safranin stain, Gram’s iodine mordant, ethanol decolorization, crystal violet counterstain Difficulty: Easy ASM Standard: 32 20. It is important to fix bacterial smears on a slide for which of the following reasons? A. to attach them to the slide* B. to cause swelling of the cell to make interior structures more visible C. to enhance the uptake of stains D. to provide a nutrient medium to sustain the bacteria Difficulty: Easy ASM Standard: 32 21. Which of the following is not commonly used for chemical fixation? A. acetic acid B. ethanol C. glutaraldehyde D. iodine* Difficulty: Moderate ASM Standard: 32 22. Which of the following is not involved in preparing a bacterial slide for Gram staining? A. allowing the sample to dry on the slide B. fixing the specimen to the slide C. placing a smear on the slide D. preparing a wet mount* Difficulty: Moderate ASM Standard: 32 23. Which of the following most specifically refers to stains with positively charged chromophores? A. acid-fast dyes B. acidic dyes C. basic dyes* D. positive dyes Difficulty: Moderate ASM Standard: 32 24. Which of the following most specifically refers to a stain that dyes a specimen rather than the background? A. counterstain
B. mordant C. negative stain D. positive stain* Difficulty: Moderate ASM Standard: 32 25. Which of the following describes the difference between the Ziehl-Neelsen and Kinyoun acid-fast staining techniques? A. The Ziehl-Neelsen technique uses a counterstain and the Kinyoun technique does not. B. The Ziehl-Neelsen technique uses an acidic dye and the Kinyoun technique does not. C. The Ziehl-Neelsen technique uses heat and the Kinyoun technique does not.* D. The Ziehl-Neelsen technique uses two dyes and the Kinyoun technique does not. Difficulty: Moderate ASM Standard: 32 26. Which of the following described the difference between gram-positive and gram-negative cells that causes them to stain differently after Gram staining? A. Gram-positive cells have a mycolic acid layer in their cell walls that holds in stain, whereas gram-negative cells lack this layer. B. Gram-positive cells have capsules and gram-negative cells have S layers. C. Gram-positive cells have thicker cell membranes than gram-negative cells. D. Gram-positive cells have thicker peptidoglycan layers in their cell walls than do gramnegative cells.* Difficulty: Moderate ASM Standard: 7, 32, 34, 36 27. Which of the following would not potentially cause a gram-positive cell to appear gramnegative after Gram staining? A. counterstaining with crystal violet instead of safranin* B. exposing the cells to ethanol for too long C. using older bacterial cultures D. using safranin as a primary stain Difficulty: Moderate ASM Standard: 32, 34, 36 28. Which of the following does not cause the probe to move up and down above the specimen in atomic force microscopy? A. chemical bonding B. electrostatic forces C. van der Waals forces D. variations in current*
Difficulty: Difficult ASM Standard: 32 29. Quantum tunneling of electrons is important in the mechanism underlying which microscope type? A. AFM B. SEM C. STM* D. TEM Difficulty: Moderate ASM Standard: 32 30. Which of the following is the chemical in some bacterial cells’ walls that makes themresist decolorization after acid-fast staining? A. acetic acid B. mycolic acid* C. peptidoglycan D. phospholipid Difficulty: Moderate ASM Standard: 32 31. Gram staining is useful for bacterial identification. Which of the following is another way it is most useful? A. Knowing Gram staining results allows a researcher to know which organisms abacterium can infect. B. Knowing Gram staining results allows a researcher to select the appropriate growth medium for optimal bacterial growth. C. Knowing Gram staining results is helpful in choosing an effective antibiotic.* D. Knowing Gram staining results is helpful in understanding a bacterium’s metabolic requirements. Difficulty: Difficult ASM Standard: 7, 23 32. Which of the following is not true regarding capsule staining? A. Capsules are typically stained using basic dyes.* B. Capsule staining does not require heat fixation in advance. C. Capsule staining requires careful selection of a stain that can stain the capsule itself. D. Capsule staining typically involves negative staining. Difficulty: Difficult ASM Standard: 7, 23 33. Because endospores are difficult to stain, which of the following is generally needed?
A. Heat must be used to make the endospore take up stain. B. Mycolic acid must be added to encourage the endospore to take up stain. C. Negative staining must be used to stain endospores because they do not absorb stain.* D. The cells must be cooled to make the endospore more brittle prior to staining. Difficulty: Difficult ASM Standard: 7, 32 34. When endospores are stained using the Schaeffer-Fulton method, which of the following correctly describes how they appear after staining? A. The endospore appears green within a pink cell, because only the endospore retained the primary stain.* B. The entire cell appears green because the endospore surrounds all the vegetative material. B. The entire cell appears pink because the endospore surrounds all the vegetative material. C. The entire cell appears pink except for a clear area representing the endospore. Difficulty: Moderate ASM Standard: 6, 7, 32 35. Specimens for TEM are prepared by doing which of the following? A. dehydrating the specimen in ethanol and then coating it in a material that will repel electrons B. sputter coating with a substance such as gold to repel electrons C. using an ultramicrotome to cut very thin sections from samples embedded in plastic resin* D. using chemical fixation, followed by standard staining techniques such as the Gram stain Difficulty: Difficult ASM Standard: 32 True/False 36. In fluorescence, emitted photons have the same amount of energy as absorbed photons. Answer: False Difficulty: Easy ASM Standard: N/A 37. A microscope with very high magnification and low resolution would allow you toclearly see small structures. Answer: False Difficulty: Easy ASM Standard: 6 38. The difference between a simple microscope and a compound microscope is that the latter only has one lens.
Answer: False Difficulty: Easy ASM Standard: N/A 39. Flagella staining is very useful for diagnostic purposes in medical settings. Answer: False Difficulty: Moderate ASM Standard: 7, 32 40. The transmission electron microscope and scanning electron microscope produce very similar images, but the former can be show three-dimensional external structures. Answer: False Difficulty: Moderate ASM Standard: 6, 32 41. Differential interference contrast microscopy produces three-dimensional images of specimens. Answer: True Difficulty: Moderate ASM Standard: 32 42. During specimen preparation for transmission electron microscopy, the specimensare dehydrated in alcohol and embedded in plastic resin. Answer: True Difficulty: Difficult ASM Standard: 32 43. In atomic force microscopy, the movement of the probe tip is determined using Hooke’slaw of elasticity. Answer: True Difficulty: Difficult ASM Standard: 32 Matching 44. Match each term with the best definition. A. amplitude i. electromagnetic radiation within certain parameters B. frequency ii. the height of a wave peak or depth of a wave trough C. visible light iii. the rate of vibration of a wave D. wavelength iv. the distance between two wave peaks
Answers: A. ii., B. iii., C. i., D. iv. Difficulty: Easy ASM Standard: N/A 45. Match each term with the best definition. A. absorbance i. Light waves change direction when they enter a new medium. B. diffraction ii. Two waves interact. C. interference iii. A wave travels through something. D. refraction iv. A material captures light energy. E. transmission v. Light bends or scatters as it interacts with objects or openings. Answers: A. iv., B. v., C. ii., D. i., E. iii. Difficulty: Moderate ASM Standard: N/A 46. Match each type of microscope with a common use for that microscope type. A. brightfield i. commonly used clinically; helpful in distinguishing living from dead cells, finding molecules within a cell, and for immunostaining B. darkfield ii. widely used and easily available; used for examining common protists, bacteria, and tissues; stains are often needed C. fluorescence iii. uses an annular stop, refraction, and interference to produce relatively high-resolution images without stains D. phase contrast iv. used to examine an image produced with light that hits a specimen indirectly owing to the use of an opaque light stop; often used to view living microorganisms without stains E. two-photon v. often used to penetrate thick specimens, such as biofilms, with long-wavelength light Answers: A. ii., B. iv., C. i., D. iii., E. v. Difficulty: Difficult ASM Standard: 32 47. Match each type of microscopy with the best description. A. atomic force microscopy i. measures changes in current as a probe is moved at a constant height over a specimen B. scanning electron ii. measures variations in the height of a probe moving microscopy over the specimen; height variations occur to maintain a constant current C. scanning tunneling iii. yields images from electrons produced by an electron microscopy beam hitting the surface of a sputter-coated specimen D. transmission electron iv. produces images from electrons that pass through a microscopy very thin specimen, allowing internal structures to be visualized Answers: A. ii., B. iii., C. i., D. iv. Difficulty: Moderate
ASM Standard: 32 48. Match the staining procedure with the chemicals used. A. acid-fast stain i. crystal violet, iodine, ethanol, safranin B. capsule stain ii. tannic acid or potassium alum, pararosaniline or basic fuchsin C. endospore stain iii. carbolfuchsin, acid alcohol, and methylene blue D. flagella stain iv. malachite green, safranin E. Gram stain v. India ink or nigrosin, sometimes with positive staining Answers: A. iii., B. v., C. iv., D. ii., E. i. Difficulty: Moderate ASM Standard: 32 49. The choices describe possible scenarios and outcomes from Gram staining with standard stains (e.g., crystal violet and safranin). Match the scenario with the most likely outcome. A. A gram-negative cell is stained, but i. The cell will probably appear pink, which will the ethanol step is skipped. not correctly indicate its cell wall structure. B. A gram-positive cell with a severely ii. The cell will appear pink. damaged cell wall is stained. C. A healthy gram-negative cell is iii. The cell will appear purple/violet. stained. D. A healthy gram-positive cell is iv. The cell will probably appear purple/violet, stained. which will not correctly indicate its cell wall structure. Answers: A. iv., B. i., C. ii., D. iii. Difficulty: Difficult ASM Standard: 6, 32 Fill in the Blank 50. Compared with air, water has a(n) Answer: higher
refractive index.
Difficulty: Easy ASM Standard: N/A 51. The electron microscope produces high-resolution images of three-dimensional surface structures of sputter-coated specimens. Answer: scanning Difficulty: Moderate ASM Standard: 32 52. Robert Hooke published compound microscopes. Answer: Micrographia
, in which he described his observations of cork via
Difficulty: Easy ASM Standard: N/A 53.
microscopy uses an opaque stop, is useful for viewing living organisms without using stains, and produces images with a dark background. Answer: Darkfield Difficulty: Moderate ASM Standard: 32
54. Acid-fast bacteria have Answer: mycolic acids
in their cell walls that retain carbolfuschin stain.
Difficulty: Moderate ASM Standard: 6, 7, 32 55. In acid-fast staining, cells that are not acid-fast usually appear Answer: blue
.
Difficulty: Moderate ASM Standard: 32 56. During preparation of specimens for scanning electron microscopy, specimens areoften sputter coated with or a similar material. Answer: gold Difficulty: Moderate ASM Standard: 32 57. Negative staining of capsules is commonly done using India ink or Answer: nigrosin
.
Difficulty: Moderate ASM Standard: 6 32 58. An acid-fast staining technique similar to the Ziehl-Neelsen technique is called the technique. Answer: Kinyoun Difficulty: Moderate ASM Standard: 32 59. When an object is relatively small relative to a wavelength of light, diffraction is than if an object is relatively large. Answer: larger
Difficulty: Difficult ASM Standard: 32 Short Answer 60. Why is the resolution of a microscope image important? Sample Answer: A high-resolution image is clear because you can distinguish between points. If the image is low resolution, then it is fuzzy and individual structures are more difficult to see. Difficulty: Easy ASM Standard: 32 61. Who is believed to have developed the first microscopes that allowed microbes to be viewed? Sample Answer: Antonie van Leeuwenhoek is believed to have developed the first microscopes that allowed microscopes to be viewed. Difficulty: Easy ASM Standard: N/A 62. What is the name of the lens that focuses light from a microscope light source onto the specimen on the stage? Sample Answer: The lens that focuses light on the slide is called the condenser. Difficulty: Easy ASM Standard: N/A 63. Would you use immersion oil at high magnification or low magnification? Sample Answer: Immersion oil is used to view specimens at high magnification with a light microscope and only with objective lenses that are designed for oil immersion. Difficulty: Easy ASM Standard: 32 64. What is the difference between fluorescence and phosphorescence? Sample Answer: In both fluorescence and phosphorescence, a material absorbs energy from light and then emits it again at a lower energy level. However, there is a delay between light absorbance and the emission of lower energy photons in phosphorescence that does not occur in fluorescence. Difficulty: Difficult ASM Standard: N/A 65. Which lens will produce an image with greater resolution: one with a higher numerical aperture or one with a lower numerical aperture? Why?
Sample Answer: A higher numerical aperture produces an image with greater resolution, because more light can be gathered by the lens. Difficulty: Moderate ASM Standard: 32 66. How does immersion oil improve the resolution of a microscope image? Sample Answer: Immersion oil has a similar refractive index to glass. When light passes from the specimen into air, it is refracted and some is lost rather than passing through the objective. When there is oil between the specimen and the objective lens, more light enters the objective lens rather than being lost, and the image resolution is greater. Difficulty: Moderate ASM Standard: N/A 67. For what type of microscopy is an opaque light stop used, and what is its function? Sample Answer: In darkfield microscopy, an opaque stop is placed between the light source (illuminator) and the condenser lens. The stop blocks light from the illuminator from hitting the specimen directly. This means light does not hit the specimen directly and only refracted or reflected light reaches the objective, producing a bright specimen on a dark background. Difficulty: Moderate ASM Standard: N/A 68. Why is it sometimes advantageous to avoid using stains when viewing microorganisms? Sample Answer: Most stains or the process of staining can kill the specimen. It is often advantageous to view microorganisms without stains when one wishes to observe them alive (e.g., to observe their motility). Difficulty: Moderate ASM Standard: N/A 69. What is another name for differential interference contrast microscopy? Sample Answer: Differential interference contrast microscopy is also called Nomarski optics. Difficulty: Moderate ASM Standard: N/A 70. What are some common fluorochromes used in fluorescence microscopy? Sample Answer: Some common fluorochromes are Texas red, FITC, DAPI, and acridine orange. Difficulty: Moderate ASM Standard: 32 71. In immunofluorescence, what are secondary antibodies used for?
Sample Answer: Secondary antibodies bind to primary antibodies, which bind to a an antigen (i.e., a protein, sometimes as part of a pathogen) in indirect immunofluorescence assays. Difficulty: Moderate ASM Standard: 32 72. Why is it important to embed specimens in plastic resin during their preparation for TEM? Sample Answer: TEM specimens must be very thin for internal structures to be visible. An ultramicrotome is used to cut thin sections for this purpose. By embedding the specimens in plastic before cutting them, it is easier to prevent them from being damaged and compressed while being cut. Ethanol is used to help the plastic resin penetrate the cell. Difficulty: Difficult ASM Standard: 32 73. Why can electron microscopes achieve higher resolutions than light microscopes? Sample Answer: Resolution is higher when there are shorter wavelengths. The beams of electrons used by electron microscopes have shorter wavelengths than the light waves used by light microscopes. Difficulty: Difficult ASM Standard: 32 74. Why do microscopes have rheostats? What is adjusted by adjusting a microscope’s rheostat? Sample Answer: A microscope rheostat is used to adjust the amount of light on the specimen. This is important to have the optimal amount of light to view the specimen. Having too much or too little light makes the specimen difficult to see clearly. Difficulty: Difficult ASM Standard: 32 Brief Essay Essay Question Rubric RATING Failing Criteria for evaluati on
Answer does not provide an argument. Answer contains inaccuracies. Writing is poor and contains numerous grammatical
Below Average Answer fails to provide examples to support an argument. Writing is poor and grammatical errors are common. Answer is
Competent
Advanced
Answer provides an argument with one or two examples that support it. Writing is acceptable for the college level but may contain one or
Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.
mistakes and misspellings.
somewhat incoherent.
two grammatical mistakes or misspellings.
Answer is well organized and free of grammatical errors and misspellings.
0 1 2 3 POINT VALUE Assume rating/grading scale for the question ranges from 0 to 3 points. 75. Explain how direct and indirect immunofluorescence assays differ, including an explanation of why indirect immunofluorescence is more commonly used. Answer: Student answers will vary but should include the following. Direct immunofluorescence involves the use of an antibody that is attached to a fluorochrome. When the antibody binds to an antigen, the fluorochrome is visible under the fluorescence microscope and allows the location of the antigen to be visualized. In indirect immunofluorescence, a primary antibody lacking a fluorochrome binds to an antibody. Then, a secondary antibody containing a fluorochrome binds to the primary antibody. Because more than one secondary antibody may bind to a primary antibody, indirect immunofluorescence increases sensitivity and can make it easier to visualize the specimen. This is an important reason to choose indirect immunofluorescence even though direct immunofluorescence requires fewer steps. Difficulty: Moderate ASM Standard: 32, 36 76. You prepare a slide of a bacterial sample by placing bacteria on a slide and examining it under a brightfield microscope. However, it is difficult to see the bacteria because the contrast is low. What are at least two ways you could increase the contrast? Answer: Student answers will vary but should include the following. There are several ways you could increase the contrast. You could add a stain, choosing one that would likely stain the structures or cells of interest. You could also use a different form of microscopy, such as darkfield or phase contrast. Another option is to adjust the amount of light on the slide using the diaphragm and/or rheostat. Other options are also possible. Difficulty: Moderate ASM Standard: 32 77. Explain some advantages of two-photon microscopy, and explain why this typeof microscopy is not more commonly used. Answer: Student answers will vary but should include the following. Two-photon microscopy is especially valuable for penetrating thicker materials, such as biofilms. It also uses lower-energy light that is less damaging to living tissues than some other forms of microscopy. This means it can be used to obtain high-resolution images of living organisms and tissues. However, the technology is still not widely used because it is very expensive. Difficulty:
Moderate ASM Standard: 32 78. There is some debate over who invented the microscope. Explain why this debate exists and what factors help some individuals get more credit for their roles than others. Answer: Student answers will vary but should include components of the following. Multiple people worked on early microscopes, including Galileo. Antonie van Leeuwenhoek and Robert Hooke receive considerable credit for their microscopes and observations. However, it is possible that Hans Janssen and Zaccharias Janssen should receive more credit. There is considerable uncertainty about their exact work. A major reason for this is that Leeuwenhoek and Hooke published their work. Because the Janssens did not, much less is known about their work. Difficulty: Difficult ASM Standard: 31 79. Many microbes live in biofilm communities and understanding these communities is important for a variety of reasons. For example, understanding biofilm formation within wounds and medical devices is important for improving patient outcomes. What are ways that light microscopy, confocal microscopy, fluorescence microscopy, electron microscopy, and two-photon microscopy can be used to study biofilms? Answer: Student answers will vary but should include components of the following. Although light microscopes are easily available, biofilm architecture is difficult to examine under light microscopy because biofilms are too thick to easily examine throughout their structure with light microscopes without cutting and disrupting the biofilm. Confocal microscopy can be helpful in providing three-dimensional images of thicker structures, such as biofilms, but still have lower resolution than two-photon microscopes. Additionally, fluorescent stains can be used with confocal microscopy to enhance visibility with these three-dimensional images. Even without the depth of confocal microscopy, fluorescence microscopy is helpful in identifying the locations of specific molecules or cells. Electron microscopy allows high magnifications, but the specimens are distorted and can’t be viewed alive. Two-photon microscopes are especially useful because thick biofilm specimens can be viewed without distortion, but these microscopes are too expensive for general use. Difficulty: Difficult ASM Standard: 32 This file is copyright 2017, Rice University. All rights reserved.
Page 35 of 17
Chapter 3: The Cell * = Correct answer Multiple Choice 1. The idea that life could appear from nonliving materials was called which of the following? A. the cell theory B. the cellular genesis theory C. the theory of biogenesis D. the theory of spontaneous generation* Difficulty: Easy ASM Standard: N/A 2. The first known use of epidemiology to trace the source of a disease outbreak was the identification of contaminated water as the cause of cholera transmission in London. Which of the following was the physician who accomplished this? A. Joseph Lister B. John Needham C. Ignaz Semmelweis D. John Snow* Difficulty: Easy ASM Standard: N/A 3. Which of the following is a series of steps for determining the causative agent of a particular disease? A. Koch’s postulates* B. Lister’s checklists C. Pasteur’s principles D. Semmelweis’ guidelines Difficulty: Easy ASM Standard: 23 4. Which scientist performed an elegant series of experiments that finally and definitively disproved the theory of spontaneous generation? A. John Needham B. Louis Pasteur* C. Francesco Redi D. Jan Baptista van Helmont Difficulty: Easy Page 36A of S M17Standard:
N/A
5. Prokaryotes are classified into which domain(s)? A. Domain Archaea only B. Domain Bacteria only C. Domains Archaea and Bacteria only* D. Domains Bacteria and Eukarya only Difficulty: Moderate ASM Standard: N/A 6. Which term refers to a curved rod? A. bacillus B. coccus C. spirillum D. vibrio* Difficulty: Easy ASM Standard: N/A 7. When a bacterial cell with a cell wall is placed in salt water with a higher-solute concentration than the cell cytoplasm, the cell will undergo which of the following? A. crenation B. crenolysis C. lysis D. plasmolysis* Difficulty: Moderate ASM Standard: 8, 22 8. The bacterial chromosome located in which of the following? A. the capsule B. the nucleoid region* C. the nucleus D. the thylakoids Difficulty: Easy ASM Standard: N/A 9. Which scientist thought spontaneous generation had occurred in flasks of broth after the broth had been boiled? A. John Needham* B. Louis Pasteur C. Francesco Redi D. Jan Baptista van Helmont Difficulty: Moderate ASM Standard: N/A Page 37 of 17
10. Which of the following is not evidence for the endosymbiotic theory? A. Chloroplasts and mitochondria contain ribosomes that resemble prokaryotic ribosomes. B. Chloroplasts and mitochondria contain their own DNA that resembles prokaryotic DNA. C. Chloroplasts and mitochondria have structures that resemble prokaryotic cell walls.* D. Chloroplasts and mitochondria reproduce using binary fission, like prokaryotic cells. Difficulty: Moderate ASM Standard: 1 11. Which physician realized that doctors were causing maternal deaths by failing to wash their hands while assisting during childbirth? A. Girolamo Fracastoro B. Joseph Lister C. Louis Pasteur D. Ignaz Semmelweis* Difficulty: Easy ASM Standard: 23 12. How did Joseph Lister dramatically improve surgical outcomes? A. by developing new antibiotics B. by developing new ways to circulate air within surgical facilities C. by using phenol as an antiseptic and disinfectant during surgery* D. by using vaccination against communicable diseases Difficulty: Easy ASM Standard: 14, 23 13. Sporulation generally occurs under which of the following circumstances? A. when conditions are unfavorable or there are insufficient nutrients* B. when microbes are exposed to a new, favorable environment C. when microbes are under little stress and can become dormant D. when resources become highly abundant Difficulty: Moderate ASM Standard: 8, 22 14. Which of the following is not a difference between endospores and vegetative cells? A. Vegetative cells are metabolically active, whereas endospores are dormant. B. Vegetative cells are more resilient due to their metabolic activities, whereas endospores are more sensitive to change.* C. Vegetative cells normally have enzyme activity, whereas endospores do not show enzymatic activity.
Page 38 of 17
D. Vegetative cells stain easily using normal staining protocols, whereas endospores are difficult to stain without special endospore stains. Difficulty: Moderate ASM Standard: 8 15. Immediately following asymmetric cell division during sporulation, which of the following structures contains the DNA and goes on to develop into an endospore? A. cortex B. forespore* C. hindspore D. spore coat Difficulty: Moderate ASM Standard: 8 16. Which of the following gives the correct order of the stages of sporulation? A. Cortex formation, formation of a double layer of membrane, DNA replication, spore release B. DNA replication, formation of a double layer of membrane, cortex formation, spore release* C. DNA replication, spore release, cortex formation, formation of a double layerof membrane D. Formation of a double layer of membrane, DNA replication, spore release, cortex formation Difficulty: Moderate ASM Standard: 8 17. Which of the following is not a clinically significant, spore-forming bacterium? A. Bacillus anthracis B. Clostridium botulinum C. Clostridium difficile D. Escherichia coli* Difficulty: Moderate ASM Standard: 8 18. All cells have which of the following? A. capsule B. cell membrane* C. cell wall D. nucleus Difficulty: Moderate ASM Standard: 8 Page 39 of 17
19. Which term refers to proteins that extend across the plasma membrane from one side to the other? A. glycoproteins B. lipoproteins C. peripheral proteins D. transmembrane proteins* Difficulty: Moderate ASM Standard: N/A 20. In which types of organisms are phospholipids with branched chains common? A. archaea* B. bacteria C. eukaryotes D. all of the above Difficulty: Moderate ASM Standard: N/A 21. The lipopolysaccharide molecule is an important component of the cell membranes of which organisms? A. archaeans B. eukaryotes C. gram-negative bacteria* D. gram-positive bacteria Difficulty: Moderate ASM Standard: 8, 23 22. Capsules and slime layers are examples of which type of structure? A. cell walls B. glycocalyces* C. peptidoglycan layers D. S-layers Difficulty: Moderate ASM Standard: 8 23. Bacteria use flagella to move purposefully toward or away from a chemical by which of the following? A. having alternating runs and tumbles of equal lengths B. increasing the length of runs and decreasing the length of tumbles* C. increasing the length of tumbles and decreasing the length of runs D. using only runs
Page 40 of 17
Difficulty: Moderate ASM Standard: 8, 22 24. Which of the following is not a typical difference between eukaryotes and prokaryotes? A. Eukaryotes have ester-linked phospholipids, whereas prokaryotes have ether-linked or ester-linked phospholipids. B. Eukaryotic cell walls lack peptidoglycan in their cell walls (if present), whereas many prokaryotes use peptidoglycan in their cell walls. C. Eukaryotic cells have histones for DNA organization, whereas prokaryotic cellshave histone-like proteins or nucleoid-associated proteins involved in DNA organization. D. Eukaryotic cells typically have circular chromosomes, whereas prokaryotic cells typically have linear chromosomes.* Difficulty: Moderate ASM Standard: N/A 25. In eukaryotic cells, the function of the nucleolus is which of the following? A. It is where all the nuclear DNA is located. B. It is where cellular respiration takes place. C. It is where ribosomal RNA is synthesized and ribosome assembly begins.* D. It is where transcription and translation of all gene products take place. Difficulty: Moderate ASM Standard: 9 26. Microfilaments are composed of which structure? A. actin* B. desmin C. keratin D. tubulin Difficulty: Moderate ASM Standard: N/A 27. Which of the following are not types of inclusions in bacterial cells? A. carboxysomes B. magnetosomes C. thylakoids* D. volutin granules Difficulty: Difficult ASM Standard: 8 28. Which of the following is not true of archaeal membranes? A. They are sometimes monolayers. B. They have branched phospholipids. Page 41 of 17
C. They have ether linkages instead of ester linkages. D. They have peptidoglycan linkages attaching their membranes to their cell walls.* Difficulty: Difficult ASM Standard: N/A 29. Which cell would best be able to survive in a hypotonic environment? A. a gram-positive bacterium in a medium containing penicillin B. a gram-positive bacterium in a medium without antibiotics* C. an animal red blood cell D. an archaeal cell lacking a cell wall Difficulty: Difficult ASM Standard: 8, 22 30. For a peritrichously flagellated bacterium, which of the following results in a run? A. alternating beating of flagella B. alternating whip-like movements of flagella C. clockwise flagellar rotation D. counterclockwise flagellar rotation* Difficulty: Difficult ASM Standard: 8 31. Which of the following is true of ribosomes? A. All prokaryotic ribosomes are 70S and eukaryotic cytoplasmic ribosomes are 80S. B. Bacterial ribosomes are 70S, whereas archaeal and eukaryotic cytoplasmic ribosomes are 80S. C. Organelle ribosomes and prokaryotic ribosomes are 70S, whereas eukaryotic cytoplasmic ribosomes are 80S.* D. Prokaryotic ribosomes are 80S, but eukaryotic cytoplasmic ribosomes are variable in size. Difficulty: Difficult ASM Standard: 1 32. Which of the following is not part of the endomembrane system? A. lysosomes B. mitochondria* C. the Golgi apparatus D. the rough endoplasmic reticulum Difficulty: Difficult ASM Standard: N/A 33. Which of the following are anchored into the plasma membrane by a basal body composed of nine triplets of microtubules? Page 42 of 17
A. eukaryotic cilia only B. eukaryotic flagella only C. eukaryotic cilia and flagella only* D. prokaryotic flagella only Difficulty: Difficult ASM Standard: 8 34. Which best describes the function of cristae? A. They aid in the proper trafficking of vesicles around eukaryotic cells. B. They are compartments for digestive enzyme storage in eukaryotic cells. C. They increase the surface area for reactions associated with cellular respiration.* D. They provide a location for the light reactions of photosynthesis in plant cells. Difficulty: Moderate ASM Standard: 8 True/False 35. One of the first recorded proponents of spontaneous generation was Aristotle. Answer: True Difficulty: Easy ASM Standard: N/A 36. All bacterial cells can form endospores. Answer: False Difficulty: Easy ASM Standard: 8 37. Some bacterial inclusions are surrounded by a phospholipid monolayer membrane. Answer: True Difficulty: Moderate ASM Standard: 8 38. The S-layer can function as a cell wall in some archaeans. Answer: True Difficulty: Moderate ASM Standard: 8 39. Prokaryotic and eukaryotic flagella have the same structure. Answer: False
Page 43 of 17
Difficulty: Moderate ASM Standard: 8, 9 40. Mitochondria contain their own DNA but chloroplasts do not. Answer: False Difficulty: Moderate ASM Standard: 1 41. Specialized organelles called hydrogenosomes are used by some eukaryotes to produce hydrogen anaerobically. Answer: True Difficulty: Difficult ASM Standard: 9 42. The extracellular matrix of animal cells generally consists mostly of phospholipids. Answer: False Difficulty: Difficult ASM Standard: N/A Matching 43. Match each term for bacterial cell arrangement with the correct illustration.
Answers: A. iii., B. v., C. ii., D. iv., E. i. Difficulty: Easy ASM Standard: N/A 44. Match each type of solution with its best description. A. hypertonic i. a solution with a lower solute concentration than that inside the cell B. hypotonic ii. a solution with a concentration equivalent to that inside of the cell C. isotonic iii. a solution with a higher solute concentration than that inside the Page 44 of 17
cell Answers: A. iii., B. i., C. ii. Difficulty: Moderate ASM Standard: 20 45. Match each organelle with its best description. A. chloroplast i. is acidic; contains digestive enzymes B. Golgi apparatus ii. synthesizes proteins C. lysosome iii. has its own DNA; is site of cellular respiration D. mitochondrion iv. has its own DNA; is site of photosynthesis E. rough endoplasmic reticulum v. modifies materials and packages them into vesicles Answers: A. iv., B. v., C. i., D. iii, E. ii. Difficulty: Moderate ASM Standard: N/A 46. Match each organelle with its best description. A. nucleus i. used for lipid synthesis and detoxification B. peroxisome ii. used to transport materials C. smooth endoplasmic reticulum iii. contains DNA D. vesicle iv. produces and degrades hydrogen peroxide; involved in lipid biosynthesis Answers: A. iii., B. iv., C. i., D. ii. Difficulty: Moderate ASM Standard: N/A 47. Match each cytoskeletal component with its best description. A. intermediate filaments i. contain tubulin; found in cilia and flagella; move materials and organelles in the cell B. microfilaments ii. composed of a variety of materials; important in nuclear lamina, joining cells, and other functions C. microtubules iii. contain actin and work with motor proteins; used for amoeboid motion, cell motility, cell division, and muscle contraction in animals Answers: A. ii., B. iii., C. i. Difficulty: Moderate ASM Standard: 9 48. Match each cell’s characteristics with the correct domain or domains. Some domains may be used more than once. A. have 70S ribosomes as the major i. Archaea ribosome type (no 80S ribosomes) B. have ether linkages in phospholipids ii. Bacteria C. have histones or histone-like proteins iii. Eukarya Page 45 of 17
D. have peptidoglycan cell walls E. have sterols in the cell membrane Answers: A. i. and ii, B. i., C. i. and iii., D. ii., E. iii. Difficulty: Difficult ASM Standard: 8, 9 Fill in the Blank 49. The is the outermost portion of an endospore. Answer: exosporium Difficulty: Easy ASM Standard: 8 50. The plasma membrane is a(n) Answer: phospholipid
bilayer.
Difficulty: Easy ASM Standard: N/A 51. Microtubules are filaments composed of Answer: Tubulin
dimers.
Difficulty: Easy ASM Standard: N/A 52. The theory that states chloroplasts and mitochondria arose from prokaryotes that lived within other cells is the theory. Answer: endosymbiotic Difficulty: Moderate ASM Standard: 1 53. The model is the model currently used to explain the structure of the plasma membrane. Answer: fluid mosaic Difficulty: Moderate ASM Standard: N/A 54. The general term for molecules that bind to structures such as receptors, including the molecules that bind to receptors in cell-mediated endocytosis, is . Answer: ligand Difficulty: Moderate ASM Standard: N/A Page 46 of 17
55. Most cell membranes are phospholipid bilayers, but archaeans sometimes have phospholipid . Answer: monolayers Difficulty: Moderate ASM Standard: 8 56. The first known epidemiological study found that the disease from wells in London. Answer: cholera
was being spread
Difficulty: Moderate ASM Standard: 23 57. Some large molecules, viruses, and bacteria enter eukaryotic cells using endocytosis. Answer: receptor-mediated Difficulty: Moderate ASM Standard: N/A 58. If a protozoan cell (with no cell wall) is placed into distilled water (with all solutes removed), water would flow the cell and the cell would . Answer: into, lyse Difficulty: Difficult ASM Standard: 22 59.
is a form of transport used by bacteria, but not by eukaryotic cells, to move materials across the cell membrane and into the cell. Answer: Group translocation Difficulty: Difficult ASM Standard: 22
Short Answer 60. What two terms describe molecules that consist of protein and carbohydrate? Sample Answer: A protein with a sugar component is called a glycoprotein or proteoglycan, depending on its specific structure. Difficulty: Easy ASM Standard: N/A
Page 47 of 17
61. What type of organisms sometimes have a plasma membrane that is a monolayer? Sample Answer: Some archaeans have a plasma membrane that is amonolayer. Difficulty: Easy ASM Standard: 8 62. What is an extracellular matrix and what functions can it perform? Sample Answer: Cells that lack a cell wall, such as animal cells, often have an extracellular matrix of carbohydrate and protein (proteoglycans). This helps provide structure and stability, among other functions. Difficulty: Easy ASM Standard: N/A 63. What is a hydrogenosome? Sample Answer: Hydrogenosomes are organelles found in some anaerobic eukaryotes. They resemble mitochondria, are used to produce hydrogen anaerobically, and typically do not have DNA or ribosomes. Difficulty: Easy ASM Standard: N/A 64. What is the difference between phagocytosis and pinocytosis? Sample Answer: Phagocytosis is a type of endocytosis in which large particles are engulfed. In contrast, small molecules or liquids are taken up through pinocytosis. Difficulty: Moderate ASM Standard: N/A 65. Both prokaryotes and eukaryotes have ribosomes, but some antibiotics specifically target prokaryotic ribosomes. How is it possible to use these antibiotics to treat human diseases and how do they affect eukaryotic cells? Sample Answer: All medications can potentially have harmful effects, but it is possible to target prokaryotic ribosomes without targeting eukaryotic cytoplasmic ribosomes, because they are different. Prokaryotes have 70S ribosomes and eukaryotes have 80S cytoplasmic ribosomes. However, eukaryotic organelle ribosomes are 70S ribosomes and these can potentially be harmed by these antibiotics, resulting in negative side effects. Difficulty: Moderate ASM Standard: 7, 14, 23 66. Why is the plasma membrane considered a fluid mosaic? Sample Answer: The phospholipids in the plasma membrane are considered fluid in that they can move within the membrane. Proteins are embedded in the membrane in a mosaic and are also often capable of movement although they may be anchored in place.
Page 48 of 17
Difficulty: Moderate ASM Standard: N/A 67. What is the difference between facilitated transport and active transport? Sample Answer: Facilitated transport and active transport both use proteins as carriers or channels to transport materials across the cell membrane. However, facilitated transport moves materials down their concentration gradient without requiring energy, whereas active transport moves materials up their concentration gradient (i.e., from low to high concentration), which requires energy to power the process. Difficulty: Moderate ASM Standard: 22 68. How do the components of bacterial cell walls differ from the components of archaeal cell walls? Sample Answer: Bacterial cell walls commonly contain peptidoglycan, whereas archaeal cell walls do not. There is more diversity in archaeal cell wall composition. Archaeal cell walls may contain pseudopeptidoglycan, glycopeptide, polysaccharide, or protein. Difficulty: Moderate ASM Standard: 8 69. How do eukaryotic cell wall components differ from bacterial cell wall components? Sample Answer: The major component of bacterial cell walls is peptidoglycan. Many eukaryotes lack cell walls. In eukaryotes that have cell walls, the major components are cellulose, chitin, silica, agar, calcium carbonate, or carrageenan. Difficulty: Moderate ASM Standard: 9 70. Prokaryotes do not have chloroplasts, but some are photosynthetic. What structures do cyanobacteria use for photosynthesis? Sample Answer: Cyanobacteria use sections of their plasma membrane, where it is folded into thylakoids, for photosynthesis. Difficulty: Moderate ASM Standard: 8 71. How do prokaryotic flagella differ from eukaryotic flagella? Sample Answer: Prokaryotic flagella are rigid and made up of different material (i.e., flagellin or the archaeal equivalent [students may use the term “archaellin,” but it is not in the text]). Eukaryotic flagella are more flexible and consist of tubulin, with microtubules that are arranged in pairs in a 9+2 array. In contrast, prokaryotic flagella consist of stiff spiral filaments. The movement of the flagella differs: Prokaryotes have a propeller-like motionand eukaryotes have a whiplike motion. Difficulty: Moderate Page 49 of 17
ASM Standard: 8 72. Lysosomes are used for digestion in eukaryotes.What is an advantage of having a specialized structure for this purpose? Sample Answer: Lysosomes are acidic and contain digestive enzymes. By having these in a compartment, it prevents the lysosomal contents from damaging other parts of the cell. Difficulty: Moderate ASM Standard: 9 73. Giardia lamblia is a protist that causes gastrointestinal disease in humans. It hasmitosomes, which appear to be reduced mitochondria. It also has reduced endoplasmic reticulum and Golgi apparati. Why do you think this species is able to survive with reduced cellular components? Sample Answer: Giardia lamblia is a parasite, so it can rely on its host for many functions. Because it can obtain these functions from its host, it no longer needs the machinery to make them itself. Difficulty: Difficult ASM Standard: 9 74. Penicillin inhibits cell wall synthesis in bacteria. Under certain conditions, bacteria can survive without a cell wall. Why is penicillin often effective in killing pathogenic bacteriaby inhibiting cell wall synthesis? Under what conditions would bacteria be able to survive penicillin treatment? Sample Answer: Penicillin damages growing cell walls by inhibiting cell wall synthesis. Once the cell wall is damaged, the bacterial cell can survive in an isotonic solution. However, bacteria often live in hypotonic environments, so water would flow into cells lacking cell walls and the cells would burst. Bacteria could survive penicillin treatment if they were in an isotonic solution. (Students may also mention that bacteria could survive better if they were not actively growing and synthesizing penicillin). Difficulty: Difficult ASM Standard: 7, 14, 23 Brief Essay Essay Question Rubric RATING Failing Criteria for evaluati on
Answer does not provide an argument. Answer contains inaccuracies. Writing is
Page 50 of 17
Below Average Answer fails to provide examples to support an argument. Writing is poor and
Competent
Advanced
Answer provides an argument with one or two examples that support it. Writing is
Answer clearly provides an argument with two or more excellent examples that support it;
poor and contains numerous grammatical mistakes and misspellings.
grammatical errors are common. Answer is somewhat incoherent.
acceptable for the college level but may contain one or two grammatical mistakes or misspellings.
student makes the argument clearly and eloquently. Answer is well organized and free of grammatical errors and misspellings.
0 1 2 3 POINT VALUE Assume rating/grading scale for the question ranges from 0 to 3 points. 75. Mitochondria are unable to survive outside of eukaryotic cells. If they originated from ancestral prokaryotes, as proposed by the endosymbiotic theory, then why can’t they survive independently? Answer: Student answers will vary but should include components of the following. Over time, mitochondria and their host cells evolved to be dependent on each other. For example, many mitochondrial genes transferred to the cell nucleus. This means that the mitochondrion does not have all its genes; therefore, it cannot perform all its functions if it is removed from the eukaryotic cell. Difficulty: Moderate ASM Standard: 1 76. Explain what happens during sporulation. Answer: Student answers will vary but should include the following. When conditions become unfavorable, some bacterial cells can form endospores. First, they copy their DNA and a membrane forms around it. A septum divides the cell, forming a forespore that will form the core of the endospore. A cortex containing calcium and dipicolinic acid is formed surrounding the forespore. As a protein spore coat forms, the outer cell develops into an exosporium, which is released from the parent cell. (This is summarized in Figure 3.20). Difficulty: Moderate ASM Standard: 8 77. In osmosis, water moves across a semipermeable membrane in response to a concentration gradient. For example, osmosis could occur if a cell were placed into a solution of concentrated NaCl. Why don’t the sodium and chloride ions cross the membrane instead of just water? Answer: Student answers will vary but should include the following. The cell membrane has a hydrophobic layer at the middle of its phospholipid bilayer. Charged ions cannot easilypass through this layer, even if they are very small. Because the sodium and chloride ions are charged, they do not pass through the membrane unless transported through a protein.
Page 51 of 17
Instead, water moves through the membrane through osmosis in response to the concentration difference.
Difficulty: Difficult ASM Standard: 22 78. You discover a new species of microbe and begin to study its characteristics. It lacks any mitochondria but has some membranous internal structures. It lacks a cell wall; however, it has a nucleus with a very small quantity of DNA. What do you think is the best classification for this organism? How can it function? Answer: Student answers will vary but should include components of the following. This species must be eukaryotic because it has a nucleus. It is probably parasitic and able to use resources from its host, allowing it to survive without its own mitochondria, with fewer genes, and with reduced organelles. Difficulty: Difficult ASM Standard: 9, 22, 28
This file is copyright 2017, Rice University. All rights reserved.
Chapter 4: Prokaryotic Diversity * = Correct answer Multiple Choice 1. Which is the best example of a population? A. all the microbes living in a particular area B. all the microbes of a particular domain living in a particular area C. all the microbes of a single species living in a particular area* D. all the microbes living within the same host Difficulty: Moderate ASM Standard: 20 2. Microbial ecology is defined as the study of which of the following? A. competitive interactions between microbes B. cooperative interactions between microbes C. interactions between individuals of a single species D. interactions between microbial populations and their environment* Difficulty: Easy ASM Standard: 20 3. Which term best describes the relationship between pathogenic bacteria and humans? A. amensalism B. commensalism C. parasitism* D. predation Difficulty: Moderate ASM Standard: 23 4. Which of the following is not a class within the phylum Proteobacteria? A. Alphaproteobacteria B. Betaproteobacteria C. Deltaproteobacteria D. Omegaproteobacteria* Difficulty: Easy ASM Standard: N/A 5. Which of the following correctly characterizes Epsilonproteobacteria? A. They are atypical (not gram positive or gram negative). B. They are gram negative.* C. They are gram positive.
D. They are gram variable. Difficulty: Easy ASM Standard: 34 6. Which describes bacteria that require low concentrations of oxygen to survive (less than that in the current atmosphere)? A. facultative anaerobes B. microaerophiles* C. obligate aerobes D. obligate anaerobes Difficulty: Easy ASM Standard: 11, 22 7. Cyanobacteria produce which of the following? A. hydrogen sulfide gas B. large quantities of ammonia C. oxygen* D. sulfuric acid Difficulty: Easy ASM Standard: 11, 22 8. Which of the following bacterial groups is thought to be most closely related to the last universal common ancestor? A. Alphaproteobacteria B. cyanobacteria C. deeply branching bacteria* D. green filamentous bacteria Difficulty: Easy ASM Standard: 5 9. Which of the following is a phylum in Domain Archaea? A. Crenarchaeotae* B. Deinococcus C. Mycoplasma D. Thermotogae Difficulty: Easy ASM Standard: 5 10. Which genus contains the nitrogen-fixing bacteria that live in legume nodules? A. Bacillus B. Escherichia
C. Rhizobium* D. Vibrio Difficulty: Moderate ASM Standard: 11, 24 11. Approximately what percentage of prokaryotes are thought to be pathogens? A. <1%* B. 12% C. 26% D. 48% Difficulty: Moderate ASM Standard: 23 12. Two species of bacteria live in near each other and use similar food resources. Which type of biological interaction does this describe? A. a competitive interaction* B. a cooperative interaction C. a mutualistic interaction D. a parasitic interaction Difficulty: Moderate ASM Standard: 23
13. Which of the following is a source of vitamin K for humans? A. Bacteroides thetaiotetraiotamicron digests foods, which release vitamin K. B. Escherichia coli in their digestive tract produces vitamin K.* C. S. epidermidis releases vitamin K from dead cells. D. their diet only Difficulty: Moderate ASM Standard: 23, 24 14. The human microbiome consists of which of the following? A. all microbes present on or in the body* B. pathogenic microbes only C. resident microbes only D. transient microbes only Difficulty: Moderate ASM Standard: 23
15. The most common bacterial genus found in plaque on teeth is which of the following? A. Fusobacterium* B. Haemophilus C. Lactobacillus D. Streptococcus Difficulty: Moderate ASM Standard: 23 16. Who authored A Manual in Determinative Bacteriology, published in 1923? A. David Bergey* B. Robert Koch C. Barry Marshall and Robin Warren D. Louis Pasteur Difficulty: Moderate ASM Standard: N/A 17. Which of the following cannot be classified as either gram positive or gram negative on the basis of the Gram staining protocol? A. Bacillus B. Escherichia C. Mycoplasma* D. Vibrio Difficulty: Moderate ASM Standard: N/A 18. Bordetella pertussis is an example of which group of organisms? A. Cytophaga-Flavobacterium-Bacteroides B. high G+C bacteria C. Proteobacteria* D. spirochetes Difficulty: Moderate ASM Standard: N/A 19. Treponema pallidum, the causative agent of syphilis, is an example of which group of organisms? A. CFB group B. planctomycetes C. proteobacteria D. spirochetes* Difficulty:
Moderate ASM Standard: N/A 20. Which of the following correctly describes the microscopic morphology of Bacteroides? A. gram-negative bacilli* B. gram-negative cocci C. gram-positive bacilli D. gram-positive cocci Difficulty: Moderate ASM Standard: N/A 21. Which best describes the metabolic activities of purple sulfur bacteria? A. They are capable of nitrogen fixation, fixing nitrogen gas into nitrates and ammonia. B. They are heterotrophic and break down organic compounds to obtain energy. C. They use light energy to oxidize hydrogen sulfide, producing sulfur and sulfuric acid.* D. They use light energy to oxidize organic compounds such as sugars. Difficulty: Moderate ASM Standard: 11 22. How do Archaea differ from Bacteria? A. Archaea are found exclusively in extreme habitats. B. Archaea have ether linkages in their cell membranes.* C. Archaea have peptidoglycan cell walls. D. Archaea lack a nucleus. Difficulty: Moderate ASM Standard: 8 23. Which of the following correctly describes the metabolism of methanogens? A. They oxidize CO 2 . B. They oxidize H 2 S. C. They produce CH4 .* D. They produce N 2 gas. Difficulty: Moderate ASM Standard: 11 24. Which best describes Halobacterium salinarum? A. It is a type of methanogen. B. It is abundant in temperate environments. C. It is an example of the deeply branching bacteria.
D. It is one of the oldest archaea.* Difficulty: Moderate ASM Standard: 5 25. Which of the following is the correct classification for the methanogens? A. Archaea* B. low G+C bacteria