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MD1240E General microbiology and bacteriology Final Exam Version 1 Closed Question MCQ – 0.4 point, Total: 20 point; True / False – 0.25 point, Total: 10 point; Fill gaps – 0.4 point, Total: 10 point. Total score – 40 point Closed questions 1. A bacterial structure involved in adherence is: (A) Capsule; (B) Lipopolysaccharide; (C) Common pili; (D) O-specific side chain; (E) Teichoic acid 2. Bacteria that synthesize organic compounds from inorganic compounds are: (A) Heterotrophs; (B) Obligate anaerobes; (C) Aerobes; (D) Facultative anaerobes; (E) Autotrophs 3. What is the most prevalent Enterobacteriaceae found in bloodstream infection? A) Escherichia; B) Yersinia; C) Shigella; D) All of the above; 4. A-B subunit structure as it relates to bacterial pathogenesis refers to the structure of: (A)Bacterial exotoxins; (B)Gram-negative bacteria endotoxin; (C)Nucleic acid inhibitor antibiotics; (D)Penicillin-binding proteins; (E)Resistance transfer factors 5. A phage that is not inactivated by proteases is called a: (A) Prophage; (B) Virulent phage; (C) Temperate phage; (D) Filamentous phage 6. Which enterobacteriaceae are lactose fermenters? A) klebsiella, shigella, yersinia; B) salmonella, shigella, yersinia; C) eschericia, klebsiella, enterobacter; D) Salmonella, shigella, citrobacter 7. Lysogenic phage conversion involves: (A)The transformation of a virulent phage to a lysogenic phage; (B)A change in bacterial phenotype due to the presence of a prophage; (C)The conversion of a prophage to a temperate phage; (D)The incorporation of a prophage into the bacterial chromosome 8. Bacteriophage containing host-cell DNA is involved in which of the following processes? (A)Transformation; (B)Conjugation; (C)Transduction; (D)Transcription; (E)Recombination 9. The exchange of allelic forms of genes is involved in which of the following processes? (A)Transformation; (B)Conjugation; (C)Transduction; (D)Transcription; (E)Recombination 10. Bacteria lacking superoxide dismutase are: (A)Heterotrophs; (B)Obligate anaerobes; (C)Aerobes; (D)Facultative anaerobes; (E)Autotrophs 11. Which microscope is used to see ultrastructure details of viruses? A) fluorescence microscope; B) phase-contrast microscope; C) darkfield microscope; D) Transmission electron microscope 12. A virus measures 180 nm in diameter. What is its length in μm? A) 180 μm; B) 18μm; C) 0.18μm; D) 0.018μm 13. Which of the following statements is INCORRECT regarding prokaryotic cells? A) Their DNA is not enclosed within a membrane; B) They lack membrane-enclosed organelles; C) They typically have a circular chromosome; D) They reproduce by binary fission; E) They lack a plasma membrane.

14. According to the binomial nomenclature, in the name “Staphylococcus aureus” Staphylococcus is the A) class; B) genus; C) species; D) family 15. In Figure 2, which diagram shows a gram-negative cell wall? A) a; B) b; C) both a and b; D) neither a nor b; E) The answer cannot be determined based on the information provided.

16. The 70S procaryotic ribosomes consist of? A) Two 40S subunits; B) a 50S and a 30S subunit; C) a 40S and a 30S subunit; D) a 50S and a 20S subunit. 17. What term is defined as a certain segment of DNA that contains the necessary code to make a protein or RNA molecule? A)Genome; B)Chromosome; C)Gene; D) Nucleotide; E)Plasmid 18. What is the purpose of bacterial endospores? A)Allow the bacterium to make hundreds of "seeds" to spread on the wind; B)Help the bacterium to differentiate into faster growing stages of bacteria; C)Allow the bacterium to survive the absence of oxygen; D)Allow the bacterium to survive extended periods of heat or dryness. 19. If two organisms have similar rRNA sequences, you can conclude that they A) live in the same place; B) evolved from a common ancestor; C)will have different G-C ratios; D) will both ferment lactose; E) mated with each other. 20. Bacteria divide by a process known as what? A)Budding ; B)Snapping division; C)Binary fission; D) Zygote fusion; E)Endospore formation 21. Bacterial growth phase where cellular division seems to have decreased or ceases for a period of time: A) The Lag Phase; B) The Log Phase; C) The Stationary Phase; D) The Death Phase 22. What did Francis Griffith's experiments with Streptococcus pneumoniae and laboratory mice demonstrate? A)Plasmids were present in bacteria; B)Bacteria could be transformed by the DNA of other bacteria; C)Bacteria could be infected with viruses; D)Encapsulated bacteria are more virulent than nonencapsulated strains; E)Eucaryotes could be transfected with bacterial DNA 23. What term is defined as an interrelationship between two or more free-living organisms that is beneficial to both ? A) Synergism ; B) Mutualism; C) Commensalism; D) Parasitism; E) Antagonism 24. The term obligate anaerobe refers to an organism that: A) doesn't use oxygen but tolerates it; B) is killed by oxygen; C) uses oxygen when present or grows without oxygen when oxygen is absent; D) prefers to grow without oxygen

25. Extremophiles are most commonly what type of microorganism? A)Algae ; B) Protozoa; C) Yeasts; D) Archeae: E) Molds 26. Acineotbacter baumanii colonized the bile duct of a patient following his liver transplant surgery. This is an example of a? A) communicable disease; B) latent infection; C) nosocomial infection; D) sporadic disease; E) None of the answers is correct 27. Following infections can be caused by Staphylococcus aureus EXCEPT A)Staphylococcal enterotoxicosis; B) Toxic shock syndrome; C) Folliculitis; D) Scarlet fever; E) Osteomylitis 28. The mode of action of tetracycline is to A) inhibit cell wall synthesis; B) inhibit nucleic acid synthesis; C) injure the plasma membrane; D) inhibit protein synthesis. 29. Which of the following is the leading cause of childbirth ( puerperal ) fever ? A)Streptococcus pyogenes; B) Pseudomonas aeruginosa; C)Eshcrichia coli; D) Staphylococcus aureus; E)Clostridium perfringens 30. Which of the following antibiotics has a beta-lactam ring? A) Cephalosporin; B)Tetracycline; C)Chloramphenicol; D)Ciprofloxacin 31. Which of the following is the largest taxonomic group among bacteria? A)Actinobacteria; B)Firmicutes; C) Proteobacteria; D)Spirochetales; E) Non –proteobacteria 32. What is the name of the causative agent of the Pneumonic and Bubonic Plague? A) Yersinia enterocolitica; B)Yersinia pseudotuberculosis; C)Yersinia pesitis; D)Yersinia intermedia 33. Bacteria whose optimal growth occurs between pH 0 and 5.5 are called? A)Alkalophiles; B) Neutrophiles; C)Acidophiles 34. What is the major virulence factor of Streptococcus pneumoniae? A)M protein; B)Pyogenic exotoxins; C) capsule; D) DNAse; E) Hyaluronidase 35. What is the primary habitat for many Bacillus species? A)Humans and other large primates; B) Dust; C) Water; D) Herbivores; E) Soil 36. How do the endospores causing cutaneous anthrax enter the body? A)Through breathing; B)By consuming contaminated foods; C)Through small cuts or abrasions in the skin; D)Through sexual activity; E)Through insect vectors 37. Which of the following genera is anaerobic gram-negative rod shape bacteria ? A) Escherichia; B) Staphylococcus; C) Bacteroides; D) Treponema; E) Neisseria 38. What major life-threatening effect does botulin toxin have on the body? A)It causes excitation of neurons; B)It stimulates the removal of fluid from the tissues; C)It stimulates increased intestinal motility; D)It paralyzes the muscles of the respiratory tract; E)It prevents gastrointestinal motility. 39. What is the virulence factor in Mycobacterium tuberculosis that prevents the organisms' destruction by lysosomes within macrophages? A)Cord factor; B)Exotoxin; C) M protein: D) Capsule; E) Endotoxin 40. Saliva and lacrimal fluids contain this enzyme that destroys bacteria. A) reverse transcriptase; B) pepsin; C)amylase; D)trypsin; E)lysozyme

41. Which of the following antibiotics interfere with cell wall synthesis?

A) sulphonamides; B) macrolides; C) cephalosporins; D) tetracyclines; E) quinolones 42. In a microscopy sample preparation the heat fixation is used for: A) Washing away excessive bacterial cells; B) better visualization of morphological shapes of bacteria; C) Better penetration of stain; D) coagulation of the bacterial proteins and fixation to the glass surface 43. How are the streptococci differentiated from the staphylococci when viewed microscopically following the Gram stain procedure? A) Staphylococci are Gram positive, while streptococci are Gram negative; B)Staphylococci are Gram positive and grow in grape-like clusters, while streptococci are also Gram positive, but grow in chains; C)Staphylococci are Gram positive cocci, while streptococci are Gram positive bacilli; D)Staphylococci are Gram negative bacilli, while streptococci are Gram negative cocci; E)They cannot be differentiated microscopically 44. Which of the following procedures has bactericidal effect? A) Membrane filtration; B) Ionizing radiation;C) Freeze-drying;D) Deep freezing 45. Pasteurization involves the: A) exposure of food to high temperatures for short periods to destroy harmful microorganisms; B) exposure of food to heat to inactivate enzymes that cause undesirable effects in foods during storage; C) fortification of foods with vitamins A and D; D) use of irradiation to destroy certain pathogens in foods. 46. The McFarland standards represent a specific degree of turbidity. What is the degree of turbidity used for? A)To visually standardize the growth of bacterial cultures; B)To visually standardize the pH of bacterial cultures; C)To visually standardize the level of antimicrobial resistance; D)To visually standardize the growth factors available to the bacterial cultures. 47. Which test is used to differentiate α-hemolytic S. viridans from α-hemolytic S. pneumoniae? A) Bacitracin test; B) Novibiocin test; C) Optochin test; D) Penicillin test 48. What sugar is fermented by the coliforms that is NOT fermented by most enteric pathogens? A)Fructose; B) Glucose; C) Lactose; D) Sucrose 49. What is the purpose of filling the bottom tray of the API strip holder with water? A)To dissolve reagents; B)To provide a humidified chamber for the biochemical tests; C)The bottom tray of the API strip holder does not need to be filled with water; D)None of the above 50. Which of the following species is coagulase –positive? A)S. epidermidis; B)S. capitis; C) S. saprophyticus; D)S. aureus True/False 51. Two names of microorganisms – genus and a specific epithet( species) both are capitalized A)True B) False 52. Spontaneous generation theory means that living things come from nonliving things A)True B) False 53. The theory of biogenesis refers to the development of life forms from preexisting life forms A) True B) False

54. The process of pasteurization is named after the German scientist Robert Koch . A) True B) False 55. The highest level in the taxonomic hierarchy is "Kingdom." A) True B) False 56. The chromosomes of both procaryotes and eucaryotes are subdivided into genes. A) True B) False 57. Synergistic chemotherapeutic effect of two drugs given simultaneously is greater than the effect of either given alone A) True B)False 58. Most normal flora of the skin are gram negative rod-shaped bacteria A)True B)False 59. Trypticase soy broth or TSB is a liquid media A)True B)False 60. Mycobacterium leprae cannot be cultured in the laboratory on artificial media. A)True B)False 61. Alkalophile is a microorganism that requires high levels of sodium chloride for growth. A)True B)False 62. A mannitol salt agar is designed for the isolation of Streptococcus spp. A) True B) False 63. Immersion Oil is used to clean the lenses of a microscope. A)True B)False 64. Bacterial endospores are easily stained with a Gram stain. A)True B) False 65. The most common cause of traveler's diarrhea is enterotoxigenic E.col A) True B) False 66. Typhoid fever differs from salmonellosis in that the incubation period for typhoid fever is much longer A)True B) False 67. Helicobacter pylori can grow in the stomach because it invades epithelial cells A)True B) False 68. The causative agent of Rocky Mountain spotted fever is an obligate intracellular parasite. A)True B) False 69. Salmonella, Shigella, Yersinia, and Serratia are all endospore –forming Gram-negative rods A)True B) False 70. Borrelia is classified as a spirochete because it possesses an axial filament A)True B) False 71. All gram-negative bacteria are classified as proteobacteria A)True B) False

72. Staphylococcus and Streptococcus can be easily differentiated in a laboratory by their ability to grow at the high salt concentration A)True B) False 73. Beta Lactam antibiotics are inhibiting the protein synthesis in the bacterial cell A) True B) False 74. A commensal bacterium does not receive any benefit from its host A)True B) False 75. The main reservoirs for the Francisella tularensis are rabbits and rodents A)True B) False 76. If a microbial drug prevents microbes from growing, it’s action is termed bactericidal

A)True

B) False

77. Brucellosis is spread to humans by human contact with Cerebrospinal fluid A) True B) False 78. The golden age of antibiotics began in 1928 with Sir Alexander Fleming's discovery of an antibacterial compound he called Salvarsan A) True B) False 79. Penicillin and its relatives specifically target bacterial cell walls, so they are selectively toxic A) True B) False 80. The use of phenol (carbolic acid) as a wound disinfectant was first practiced by Lister. A) True B) False 81. Germ theory of disease—the idea, that infectious diseases are caused by microorganisms, or germs, was developed by Josef Lister A) True B) False 82. The lowest level in the taxonomic hierarchy is Species. A) True B) False 83. If we discover a unicellular organism that lacks a nucleus and peptidoglycan we have to attribute this organism to the Archea A) True B) False 84. For a particular disease at a specific time period, morbidity rates should always be equal or greater than mortality rates. A) True B) False 85. Testing the effectiveness of a new drug for tuberculosis would be best performed on animals as an experimental study. A) True B) False 86. Diseases that are referred to as Emerging infectious diseasess have only been discovered in the past fifty years. A) True B) False 87. Normal microbiota on the operating room staff can contribute to postoperative infections A) True B) False 88. Urinary tract infections are the most common forms of nosocomial infections. A) True B) False

89. Both normal and transient flora can become opportunistic pathogens. A) True B) False 90. Reservoirs of infections are always animate objects. A) True B) False Fill gap 91. A complete hemolysis is known as beta hemolysis . This is characteristic for many pathogenic bacteria such as streptococcus pyogene aureus. 92. In the CAMP test the strain of β-hemolytic hemolytic effect of Group B streptococci

lysin

is used to increase the

chromosome, while eukaryoticchromosomes

93. Most bacteria have a circular are linear and can occur in pairs.

94. The disease that affects a large number of people in the world in a short time is called pandemic . The example of such disease in 2009 was swine Flu. 95. The laboratory technician has isolated a gram-positive rod. To identify the microbe she should perform next investigation to see if the microbe is Spore forming and can grow in aerobically conditions. 96. Burkholderia cepacia are non-fermenting gram- negative rods , often causing infection in patients with cystic fybrosis, while Burkholderia mallei is predominantly the pathogen of glanders ; 97. Tuberculosis, measles and the common cold are spread by airborne While malaria is spread by VECTOR transmission. 98. The nosocomial infections occur in hospitals disinfectant resistant bacteria. 99. The disease symptoms are changes felt by a observed by the DOCTOR .

patients and are often caused by

PATIENT

, while signs are changes

100. The most important characteristic of the autoclaving is that this method can kill bacterial Virulence factor , but it has limitation: it cannot be used for heatRESISTANT materials. 101. If we know the sequence of nucleotides within a gene, we can determine with the most accuracy the primary structure of the protein . 102. An enzyme that makes covalent bonds between nucleotide sequences in DNA is DNA ligase , and an enzyme that copies DNA to make a molecule of RNA is RNA polymerase . 103. Endotoxins are associated with CELL WALL .

GRAM NEGATIVE

bacteria and are part of bacterial

104. Botulism is caused by ingestion of a bacterial exotoxin which by chemical nature is a proteinaceous , therefore, it can be prevented by boiling food prior to consumption. 105. Staphylococcal enterotoxin is an and vomiting .

endotoxin

and causes symptoms such as

diarrhea

106. The virulence of an microorganism are determined by numbers of microorganisms that gain access to a host, evasion of host defences, and produce toxin . 107. Natural and semisynthetic penicillins are similar to cephalosporins in that all these antibiotics contain Beta lactam ring. 108. The antibiotic tetracycline binds to the 30s subunit of the ribosomeand interferes with the attachment of the tRNA to mRNA-ribosome complex. 109.The acid-fast stainis used to identify members of the genus in red color in a completed acid-fast stain. 110. The mordant in the Gram staining is mordant is to prevent the release of stain

mycobacterium .Acid-fast cells appear

iodine from the cells.

.The purpose of a

111. The pH of the adult vagina is acidic due to the conversion of glycogen to lactic acid by bacteria. 112. group a streptococcus (GAS) responsible for pharyngitis.

is the most common and most important bacteria

113. A 1-year old girl was hospitalized with fever, lethargy, and rash. Gram-negative, oxidase-positive diplococci were cultured from her cerebrospinal fluid. Her symptoms were caused by . 114.

coagulase test is used to differentiate Staphylococcus aureus from other Staphylococci.

115. A substance produced by a pathogenic agent that enables it to gain entry into the host, avoid host defenses, or obtain nutrients is called a(n) virulence factor....