Multiple Choice Identify the choice that best completes the statement or answers the question. |
| 1. | Many microscopic organisms or entities have been identified as pathogens, including all of the following except: a. | protozoa. | b. | viruses. | c. | fungi. | d. | bacteria. | e. | None of the above, all may be pathogenic. |
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| 2. | Which of the following statements about bacteria is false? a. | A small percentage of bacteria are pathogenic. | b. | Some bacteria can photosynthesize. | c. | Bacteria are important decomposers. | d. | Bacteria are not cellular and are sometimes not classified as life forms. | e. | Bacteria convert atmospheric nitrogen into ammonia and then nitrates that can be used by plants. |
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| 3. | Viruses were first identified: a. | because they caused an infection and formed colonies on nutrient agar plates. | b. | because they were seen in the light microscope. | c. | because they caused an infection and were small enough to pass through filters that trapped bacteria. | d. | because they were smaller than bacteria and had all the properties of living organisms. | e. | because they caused an infection and were seen in the electron microscope. |
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| 4. | The protein coat of a virus is called the: a. | capsule. | b. | capsid. | c. | exospore. | d. | phage. | e. | pilus. |
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| 5. | Viruses that attack bacteria are called: a. | phages. | b. | bacteriods | c. | prions. | d. | virons. | e. | viroids. |
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| | Figure 23-01 Use the figure below to answer the corresponding questions. |
| 6. | The structure of the virus in Figure 23-01 that is common to all viruses is: a. | 2. | b. | 3. | c. | 4. | d. | 5. | e. | All of the above. |
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| 7. | In Figure 23-01, the function of the structure labeled 3 is: a. | attachment to a host cell. | b. | locomotion. | c. | mate recognition. | d. | replication. | e. | to take over host cell mechanisms. |
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| 8. | Viruses are classified by: a. | the sequence of their DNA. | b. | structural similarities. | c. | the sequence of their rRNA genes. | d. | the traditional Linnaean binomial nomenclature system. | e. | an international committee. |
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| 9. | Viruses: a. | are very tiny cells on the order of 500 nm. | b. | contain both RNA and DNA. | c. | cannot independently perform metabolic activities. | d. | have a standard morphology that includes a capsid, tail, and tail fibers. | e. | All of the above. |
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| 10. | Viruses: a. | are usually species-specific. | b. | may have multiple origins. | c. | are probably related to mobile genetic elements. | d. | may have escaped from cells. | e. | All of the above. |
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| 11. | Phages are being considered for: a. | vectors in gene therapy experiments. | b. | antibiotics in bacterial infections. | c. | gene transfer vectors in animal cells. | d. | being equivalent to the first living organisms. | e. | All of the above. |
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| 12. | Temperate viruses: a. | always destroy their host immediately. | b. | are considered virulent. | c. | do not always destroy their host. | d. | do not undergo a lysogenic cycle. | e. | undergo a lytic cycle. |
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| 13. | Virulent (lytic) phages: a. | infect viruses. | b. | destroy bacteria. | c. | infect, but do not destroy bacteria. | d. | infect virions. | e. | infect prions. |
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| 14. | The five stages of a lytic infection are attachment, penetration, _____________, assembly, and release. a. | lysis | b. | prophage | c. | lysogenesis | d. | transduction | e. | replication |
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| 15. | A prophage: a. | is phage DNA that is integrated into viral DNA. | b. | is phage DNA that is integrated into bacterial DNA. | c. | replicates only when the eukaryotic cell it infects replicates. | d. | is an underdeveloped lytic virus. | e. | is a bacterial cell about to lyse. |
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| 16. | The bacterium that causes botulism disease is harmless until it: a. | is infected by lytic bacteria. | b. | is infected by certain retroviruses. | c. | contains a certain prophage DNA. | d. | is irradiated by UV radiation. | e. | is infected by prions. |
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| 17. | ____________ conversion occurs when a bacterium carrying viral genes takes on new, atypical characteristics. a. | Transducing | b. | Lysogenic | c. | Prophage | d. | Lytic | e. | Reverse |
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| 18. | The specificity of viruses to different types of cells is due to _____________ sites on the host cell. a. | prophage | b. | receptor | c. | transduction | d. | penetration | e. | transcription |
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| 19. | Retroviruses differ from other RNA viruses by: a. | having reverse transcriptase instead of RNA-dependent RNA polymerase. | b. | the shape of their capsid. | c. | the way they infect their host cells. | d. | the sugar coating on their capsids. | e. | lytically destroying their hosts. |
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| 20. | Which of the following diseases is not caused by a virus? a. | rabies | b. | polio | c. | warts in humans | d. | chickenpox | e. | Lyme disease |
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| 21. | Which of the following identifies a group of DNA viruses? a. | retroviruses | b. | herpesviruses | c. | paramyxoviruses | d. | filovirus | e. | picornaviruses |
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| 22. | Viral proteins can damage host cells by: a. | increasing the rate of fermentation within the host. | b. | producing endotoxins. | c. | causing a decline in coordination and increased irritability. | d. | preventing transcription of viral nucleic acids. | e. | overwhelming the host cell with a large number of viruses. |
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| 23. | Viral infections in humans spread via the circulatory system. Viral infections in plants spread from cell to cell via: a. | endocytosis. | b. | plasmodesmata. | c. | infected seeds. | d. | pili. | e. | transformation. |
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| 24. | Human viruses can enter human cells by fusion with the cell membrane or by: a. | diffusion into the cell. | b. | passage through specific protein channels. | c. | coating themselves with lipids that cloak their entrance into the cell. | d. | endocytosis. | e. | hitchhiking onto protein signals entering the cell. |
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| 25. | Viroids cause a variety of plant diseases and are composed only of: a. | strands of RNA. | b. | strands of DNA. | c. | protein coats. | d. | peptidoglycan. | e. | a capsid. |
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| 26. | Mad cow disease is an example of an infection caused by a: a. | bacterium. | b. | bacteriophage. | c. | retrovirus. | d. | viroid. | e. | prion. |
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| 27. | _____________ is credited with the discovery of prions as a new biological principle of infection. a. | Stanley Prusiner | b. | Anton van Leeuwenhoek | c. | Dmitrii Ivanowsky | d. | Stanley Brenner | e. | Carl Woese |
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| 28. | A symptom of a transmissible spongiform encephalopathy (TSE) is: a. | degeneration of the digestive tract. | b. | progressive immune deficiency. | c. | degeneration of the brain and central nervous system. | d. | inflammation of the reproductive organs. | e. | influenza-like symptoms. |
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| 29. | The volume of a typical bacterium is about ____________ the volume of a typical eukaryotic cell. a. | equal to | b. | a half | c. | a tenth | d. | a hundredth | e. | a thousandth |
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| 30. | A chain of round bacteria would be called: a. | spirilla. | b. | diplococci. | c. | bacilli. | d. | streptococci. | e. | streptobacilli. |
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| 31. | Rod-shaped bacteria are called: a. | streptococci. | b. | bacilli. | c. | diplococci. | d. | vibrio. | e. | spirochete. |
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| | Figure 23-02 Use the figure below to answer the corresponding questions. |
| 32. | The structure in Figure 23-02 labeled C is: a. | a ribosome. | b. | the plasma membrane. | c. | the capsule. | d. | the cell wall. | e. | the flagellum. |
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| 33. | What is the function of the structure labeled A in Figure 23-02? a. | to adhere to surfaces or other bacteria | b. | to prevent phagocytosis | c. | support and protection in hypotonic conditions | d. | transmission of DNA between bacteria | e. | locomotion |
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| 34. | Even though bacteria lack membrane-bound organelles, such as chloroplasts and mitochondria, they can still perform the functions of these organelles by localizing certain metabolic enzymes on: a. | the nuclear membranes. | b. | the endoplasmic reticulum. | c. | the plasma membrane. | d. | ribosomes. | e. | the cell wall. |
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| 35. | Most bacterial cells keep from bursting in a hypotonic environment by: a. | an efficient water pump. | b. | a tough cell membrane. | c. | pumping large quantities of salts into the cell. | d. | a rigid cell wall. | e. | a stiff capsule. |
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| 36. | Gram-positive bacteria would stain __________ in a gram stain because of a thick layer of __________ in their cell walls. a. | green; peptidoglycan | b. | purple; peptidoglycan | c. | green; cellulose | d. | purple; polysaccharides | e. | red; polysaccharides |
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| 37. | The walls of Eubacteria contain peptidoglycan, which is: a. | lipids crosslinked with sugars. | b. | sugars crosslinked with proteins. | c. | a protein. | d. | a lipid. | e. | a polysaccharide. |
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| 38. | Penicillin works most effectively against gram-positive bacteria because: a. | penicillin affects cell membranes. | b. | they have a thick peptidoglycan cell wall and penicillin affects the synthesis of peptidoglycans. | c. | they have special protein channels that allow penicillin to enter the cell and halt the cell cycle. | d. | they are smaller than gram-negative bacteria and, thus, easily take up penicillin by diffusion. | e. | they contain prophages that negatively interact with penicillin. |
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| 39. | Some bacteria avoid a host’s immune system by means of: a. | efficient use of their flagella. | b. | ameboid motion. | c. | their capsule. | d. | changing their cell wall structure. | e. | eliminating the use of a membrane. |
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| 40. | Bacteria: a. | are incapable of locomotion. | b. | move by means of pili | c. | move by means of cilia. | d. | move by means of a rotating flagella. | e. | move by means of a whiplike flagella. |
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| 41. | Small circles of DNA called ______________ exist in addition to the bacterial chromosome. a. | capsids | b. | plasmids | c. | chromatids | d. | pili | e. | centromeres |
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| 42. | Small hairlike structures on the surface of bacteria are called: a. | capsids. | b. | pili. | c. | chromatids. | d. | plasmids. | e. | virons. |
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| 43. | Plasmids of bacteria often have genes involved in: a. | reproduction. | b. | motility. | c. | viral resistance. | d. | antibiotic resistance. | e. | photosynthesis. |
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| 44. | Pili are involved in adhesion of bacterial cells to a substrate or host, or in transmission of __________ between bacteria. a. | ribosomes | b. | cytoplasm | c. | vectors | d. | RNA | e. | DNA |
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| 45. | Prokaryotes have their genetic information stored in: a. | several small, circular pieces of DNA. | b. | a single, small, circular piece of DNA. | c. | a large, linear piece of DNA. | d. | several small, linear pieces of DNA. | e. | a large, circular piece of DNA. |
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| 46. | _______________ is a form of genetic exchange in bacteria that involves contact between two cells. a. | Transformation | b. | Transduction | c. | Conjugation | d. | Binary fission | e. | Budding |
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| 47. | _____________ are dormant structures formed by bacteria in response to adverse environmental conditions. a. | Capsids | b. | Endospores | c. | Exotoxins | d. | Endotoxins | e. | Heterocysts |
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| 48. | Most bacteria are: a. | photoheterotrophs. | b. | chemoheterotrophs. | c. | autotrophs. | d. | heterotrophs. | e. | chemoautotrophs. |
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| 49. | A bacterium that gains nourishment from dead organisms is referred to as: a. | an autotroph. | b. | a parasite. | c. | a saprotroph. | d. | a chemoautotroph. | e. | a pathogen. |
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| 50. | A(an) ___________________ bacterium would not be able to survive in the presence of oxygen. a. | facultative aerobic | b. | facultative anaerobic | c. | facultative autotrophic | d. | obligate aerobic | e. | obligate anaerobic |
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| 51. | The most common mode of reproduction in bacteria is: a. | binary fission. | b. | transformation. | c. | transduction. | d. | conjugation. | e. | mitosis. |
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| 52. | The first indication that Archae were different from the Eubacteria came from differences noted in their: a. | cell wall. | b. | preferred habitats. | c. | 16 S rRNA sequence. | d. | protein synthesis machinery. | e. | resistance to antibiotics. |
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| 53. | The Archaea differ from the Eubacteria and eukaryotes by having different ____________ in their cell membranes, but they are similar to eukaryotes in their ____________ process. a. | sugars; replication | b. | sugars; transcription | c. | lipids; replication | d. | lipids; transcription | e. | proteins; transcription |
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| | Figure 23-03 Use the figure below to answer the corresponding questions. |
| 54. | Which of the following groups from Figure 23-03 represents gram-negative bacteria? a. | Spirochetes | b. | Protists | c. | Methanogens | d. | Halophiles | e. | None of the above. |
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| 55. | Which of the following groups from Figure 23-03 is a member of the Eubacteria domain? a. | Fungi | b. | Halophiles | c. | Chlamydias | d. | Protists | e. | More than one of the above. |
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| 56. | About how many different species of bacteria have been classified? a. | 200 | b. | 2,000 | c. | 4,000 | d. | 20,000 | e. | 40,000 |
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| 57. | The most significant difference between the Archaea and the Eubacteria is: a. | lack of a nuclear envelope in the Archaea. | b. | the absence of the 70S ribosomes in the Eubacteria. | c. | the presence of a single filament flagellum in the Eubacteria. | d. | the absence of peptidoglycans in the cell walls of the Archaea. | e. | All of the above. |
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| 58. | One difference between the Archaea and the Eukarya is: a. | the lack of a nuclear envelope in the Archaea. | b. | the absence of the 70S ribosomes in the Archaea. | c. | the presence of membrane-bound organelles in the Archaea. | d. | the presence of peptidoglycans in the cell walls of the Archaea. | e. | the presence of simple RNA polymerase in the Archaea. |
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| 59. | One unique characteristic associated with some of the extreme halophilic Archaea is: a. | that they are found at deep-sea vents on the sea floor. | b. | that they are a source of most known antibiotics. | c. | that they have photosynthetic ability involving a purple bacteriorhodopsin pigment. | d. | that they fix atmospheric nitrogen that is then used by plants. | e. | that most form symbiotic associations. |
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| 60. | _____________ Archae are typically found in abnormally hot environments. a. | Extreme halophile | b. | Extreme thermophile | c. | Pyrrhanogen | d. | Metanogen | e. | Any of the above. |
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| 61. | Most prokaryotes belong to the: a. | Fungi. | b. | Archaea. | c. | Protista. | d. | Eubacteria. | e. | Viroids. |
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| 62. | Bacterial ____________ cause systemic symptoms such as fever, whereas bacterial ____________ cause more specific maladies. a. | phages; prophages | b. | prophages; phages | c. | endotoxins; exotoxins | d. | exotoxins; endotoxins | e. | exotoxins; phages |
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| 63. | The bacterial reproductive parasite Wolbachia is known to: a. | eradicate males from a population. | b. | convert males into females. | c. | cause infected females to lay eggs that develop without fertilization. | d. | reduce the number of males in a population. | e. | All the above. |
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| 64. | The symbiotic bacteria found in the root nodules of legumes: a. | supply the plant with the nitrogen it needs in the form of nitrates. | b. | are motile, soil-dwelling bacteria. | c. | belong to the genus Rhizobium. | d. | are gram-negative Eubacteria. | e. | All of the above. |
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| 65. | Koch’s postulates include all the following except: a. | when a sample of a pure culture is injected into a healthy host causes the same disease. | b. | a sample of the microorganism from a diseased host can be grown in pure culture. | c. | the microorganism can be recovered from an experimentally infected host. | d. | the microorganism must be visible in the electron microscope. | e. | the pathogen must be present in every individual with the disease. |
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| 66. | The first bacteria that was clearly identified as the cause of an infectious disease was: a. | Legionella pneumophila, which causes Legionnaires’ disease. | b. | Chamydia sp., which causes pelvic inflammatory disease in women. | c. | Clostridium botulinum, which causes botulism. | d. | Vibrio cholerae, which causes cholera. | e. | Bacillus anthracis, which causes anthrax. |
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Short Answer |
| 67. | Compare and contrast a virus and a bacterium. |
| 68. | List the characteristics of the following groups and identify examples for each: Archaea, Eubacteria, and Eukarya. |
| 69. | Compare and contrast the metabolic diversity of bacteria in one of the two groups below. A. | Obligate anaerobes, facultative anaerobes, and aerobes | B. | Autotrophic and heterotrophic bacteria | | |
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| 70. | Identify and briefly discuss two ecological roles filled by bacteria. |
Essay |
| 71. | Describe the theory that attempts to explain the species specificity of viruses to their hosts. |
| 72. | Discuss the distinction between gram-negative and gram-positive bacteria. In the laboratory, how is this determined? What are differences between these two groups of bacteria? |
| 73. | Describe endotoxins and exotoxins. What effects do they each have on infected persons? |