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DAMB 721 Microbiology Final Exam - a 200 Points

DAMB 721 Microbiology Final Exam - a 200 Points

DAMB 721 Final Exam - A 200 points

Your name (Print Clearly):

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I. Multiple Choice: In the blank to the left of each question, place the letter corresponding to the ONE BEST answer.

_____ 1. The HIV surface glycoprotein that binds to the CD4 receptor is:

1?? A. gp 160 B. gp 41 C. gp 120 D. HTLV III _____ 2. The E. coli fur gene: A. is regulated by temperature and pH B. is regulated by iron concentration C. codes for the production of siderophores D. codes for the production of a Shiga-like toxin E. b and c are correct F. b and d are correct G. all but a are correct

_____ 3. The first phagocytic cell to respond to microbial invasion is: A. monocyte B. macrophage C. polymorphonuclear neutrophil D. GALT macrophages E. histiocytes

____ 4. Form of gene transfer in which either a fragment of DNA or a plasmid from the donor bacterium is transferred across the of the recipient bacterium independently of a virus or : A. conjugation B. transduction C. transformation D. locomotion

_____ 5. Gram negative cells: A. when Gram stained, will be red because crystal violet is washed out of the cell with alcohol B. when Gram stained, will be blue because they retain crystal violet C. are the only bacterial cell type with D. are the only bacterial cell type with an outer membrane containing E. a and d are true

______6. In regards to the normal bacterial flora: A. The host would be better off without them. B. In general, they are present at a particular body site for brief periods of time.

2?? C. They actually prime the host immune system. D. By releasing bacteriocins and other antimicrobials they provide a barrier to colonization by exogenous . E. c and d are true F. all but a are correct

______7. A specific example of bacterial tissue tropism as it occurs in the oral cavity A. the viscosus Type 1 and Type 2 adhesins B. the invasins produced by Mycobacteria and spp. C. margination followed by diapedesis D. chemotaxis towards the C5a complement component

_____ 8. Phagocytic leukocytes are chemotactic to these bacterial products: A. fmet-LEU-PHE B. muramyl-dipeptide C. the C5a complement component D. a and b are correct E. a, b, and c are correct

______9. Penicillin is an effective bactericidal antimicrobic because: A. it has a molecular structure similar to para-amino-benzoic acid B. it interferes with DNA synthesis C. a peptidoglycan synthetic mistakes the beta-lactam ring for alanine D. it binds to the 30S ribosomal subunit and inhibits protein synthesis

______10. When using a chemical agent to disinfect instruments that may be coated with pus or sputum, a detergent or other surfactant such as Tween-80 might be added to the chemical agent in order to ensure: A. proper contact time between the instrument and the chemical agent B. that the chemical agent will have direct contact with in sputum or puss C. proper pH of the disinfecting chemical agent D. that the chemical agent will remain in solution in dry climates

3??

______11. The most dangerous pathogens that cause cross-infections in dentistry are those which: A. survive drying for long periods of time and have a long incubation period B. are transmitted by direct contact with lesions C. have a low infective dose D. are shed through desquamation

______12. Dental equipment that is reusable and that penetrates tissue, bone or pulp: A. should be disinfected with a high level B. should be disinfected with a low level disinfectant C. should be sterilized D. should only be cleaned in an ultrasonicator

______13. Barrier protection is recommended: A. for use only when treating patients infected with blood borne pathogens B. for the dentist only; the assistants are not at risk C. to protect the dental staff against aerosols of blood borne pathogens D. to prevent injury if you crash your bike

______14. According to the OSHA Bloodborne Pathogens Standard the owner of a dental office will be required to: A. Maintain medical records on their employees B. Provide Hepatitis B vaccinations free of charge C. Examine employees regarding past exposure to HIV and Hepatitis B D. Train employees regarding their occupational risk for blood borne pathogens E. all of the above F. all but c are correct

_____ 15. Which is not commonly found in dental plaque? A. S. mutans B. S. pyogenes C. S. sanguis D. S. oralis E. S. mitis

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_____ 16. Which of the following is not a member of the mutans streptococci? A. S. gordonii B. S. cricetus C. S. sobrinus D. S. mutans E. S. macacae

_____ 17. Acidoduric defines this property of bacteria: A. prolific acid production B. metabolism of intracellular carbohydrate C. the ability to survive at pH 5.5 and below D. the ability to survive and metabolize at pH 5.5 and below E. the ability to inhibit acid diffusion

____ 18. There is experimental evidence that, as a smooth surface on a tooth progresses to a carious lesion, the ratio of ______to ______will approach 5. A. mutans streptococci to S. salivarius S. mutans to S. gordonii C. S. mutans to S. sanguis A. viscosus to S. sanguis S. mutans to S. salivarius

_____ 19. The water insoluble glucan that is the matrix for dental plaque is produced by S. mutans through: A. fructosyl transferases B. glucosyl transferases that catalyze an α-1,3-bond C. glucosyl transferases that catalyze an α-1,6-bond D. invertase

_____ 20. The viridans streptococcus that is prevalent in dental plaque and in bacteremias of patients with bacterial endocarditis. A. S. gordonii B. S. agalactiae C. S. sanguis D. S. pyogenes

5?? _____ 21. Cervicofacial actinomycosis can result from the contamination of a surgical site or from trauma involving explanted endogenous organisms. What is not characteristic of this lesion? A. granulomatous inflammation B. healing with scarring C. "sulfur granules" D. formation of interconnecting sinus tracts E. fungal infection

______22. The primary virulence mechanism for and the reason no effective vaccine has been developed against diseases caused by Neisseria gonorrhoea is: A. LOS B. oxidase C. the endospore D. the polysaccharide capsule E. antigenic variation

______23. A primary virulence factor which is also the primary antigen in diseases caused by Neisseria meningitidis is: A. LOS B. oxidase C. the endospore D. the polysaccharide capsule E. antigenic variation

______24. Lecithinases (phospholipases) are toxic, membrane destroying . One of these is an important virulence factor for: A. anthrasis B. perfringens C. Corynebacterium diphtheriae D. E. Salmonella typhi

______25. In which of the following diseases does the bacterial agent produce neither an nor an endotoxin? A. B. cholera C. D. typhoid fever E. tuberculosis

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______26. The botulinum, and diphtheria toxins have the following in common: A. they are proteins comprised of two subunits; the largest subunit binds the toxin receptor while the smaller subunit is the toxic component B. they are neurotoxins C. to be activated they must be nicked by a protease and their disulfide bonds must be reduced D. they are released in the presence of a 500 kDa progenitor toxin E. Both A and C are correct

______27. The granulomatous lesion that is characteristic of tuberculosis: A. is produced by a delayed type hypersensitivity

B. is mediated by helper (CD4) T lymphocytes and cytotoxic

(CD8) T lymphocytes C. is a tubercle D. may harbor dormant M. tuberculosis for decades E. All of the above are true.

______28. The form of tuberculosis in which patients are actively shedding M. tuberculosis and therefore are most infectious: A. secondary or active tuberculosis B. primary tuberculosis C. miliary tuberculosis D. latent/dormant tuberculosis E. post healing

______29. The most important factor in the transmission of the diseases caused by Clostridia and Bacillus spp. is: A. their Gram reaction and cell morphology B. the ability to produce protein toxins C. their oxygen requirement D. the ability to produce endospores E. the ability to cause disease in animals

______30. is an etiological factor in dental caries for all of the following reasons except:

7?? A. glucosyltransferases produce glucans B. acidoduric C. acidogenic D. proteases degrade the protein fraction of enamel E. SpaA binds salivary pellicle

______31. Which of the following diseases are caused by spirochetes? A. coccidioidomycosis and blastomycosis B. thrush, athletes foot and ringworm C. lyme disease, syphilis and relapsing fever D. typhus and rocky mountain spotted fever

______32. An oral manifestation of congenital syphilis is: A. Hutchinson's teeth B. oral chancre C. thrush D. gingival stomatitis

______33. An extremely infectious manifestation of primary syphilis is: A. Hutchinson's teeth B. oral chancre C. thrush D. gingival stomatitis

_____ 34. Which of the following is not characteristic of Chlamydia ? A. two-stage life cycle B. ability to grow in vitro in ordinary broth media C. causes blindness D. elementary body is infectious

______35. An oral infection caused by Candida albicans that results from preventing contact of the maxillary mucosa with saliva: A. denture induced stomatitis B. oral thrush C. angular chelitis D. midline glossitis

8?? ______36. What pathogenic fungus is characterized by a large polysaccharide capsule? A. Histoplasma capulatum B. Blastomyces dermatitidis C. Cryptococcus neoformans D. Coccidioides immitis

______37. A dimorphic fungus that produces a lesion that resembles a tubercle: A. Histoplasma capulatum B. Blastomyces dermatitidis C. Cryptococcus neoformans D. Candida albicans

______38. The protein coat that surrounds the viral genome is the: A. matrix protein B. peplomer C. capsid D. envelope

______39. What type of viral infection causes cells to become cancer cells? A. Latent/proviral B. Persistent: chronic/slow C. Transforming/oncogenic D. Acute/lytic

______40. The distribution of microorganisms in the oral ecosystems is dependent on all of the following except: A. the availability of oxygen B. the availability of nutrients C. inhibitory products produced by bacteria D. the proximity of bacteria to the salivary pellicle

______41. Which of the following describes formation of the dental pellicle? A. adherence of crevicular fluid components such as albumin and inorganic phosphates to the enamel surface of the tooth B. calcium and phosphate bridges attach salivary mucins to the enamel surface of the tooth

9?? C. coaggregating pairs of anaerobic Gram negative rods form a climax community on the tooth surface D. Actinomyces viscosus attaches to the tooth surface via type 1 fimbriae and to Streptococcus sanguis via type 2 fimbriae

_____ 42. Which of the following describes secondary colonization of dental plaque? A. adherence of crevicular fluid components such as albumin and inorganic phosphates to the enamel surface of the tooth B. calcium and phosphate bridges attach salivary mucins to the enamel surface of the tooth C. coaggregating pairs of anaerobic Gram negative rods form a climax community on the tooth surface D. Actinomyces viscosus attaches to the tooth surface via type 1 fimbriae and to Streptococcus sanguis via type 2 fimbriae

______43. The presence of these bacteria in an oral ecosystem, indicates that the ecosystem has become anaerobic. A. oral spirochetes B. enteric bacteria C. Actinomyces viscosus and Streptococcus sanguis D. lactic acid bacteria

______44. To be considered etiologic in periodontal disease a bacterium must satisfy Socransky's Postulates. Which of the following statements is not one of Socransky's Postulates? A. Treatment eliminating the bacterium from the periodontal lesion should result in clinical improvement. B. The patient should develop high levels of antibody that is specific to the bacterium. C. The bacterium should be isolated in pure culture from the periodontal lesion. D. The bacterium should be present in high numbers in periodontal lesions and either absent or in low numbers in healthy sites.

______45. Observations of the physiologic interactions (food chain) between the microbiota in the periodontal pocket indicates that Campylobacter rectus furnishes this essential nutrient to the Porphyromonas spp. and Prevotella spp. A. isobutyrate B. protoheme

10?? C. hydrogen D. formate

______46. The specific plaque hypothesis states that: A. periodontal disease results from the build up of plaque over time B. disease results from the elaboration of toxins by the entire plaque flora C. plaque pathogenicity depends on the presence of specific microorganisms that elaborate virulence factors capable of mediating tissue destruction D. all plaque is alike and equally capable of causing disease

______47. To receive the ADA seal of approval a certain product must show that it reduces the total numbers of gram negative, anaerobic rods and spirochetes in plaque. This product is likely being tested to treat which of the following disease: A. periodontitis B. caries C. pulpitis D. periradicular infection

______48. Which virulence factor that is produced by enzymatically digests connective tissue in the periodontium and pulp? A. hemagglutinin B. fimbriae C. collagenase D. IgA protease

______49. Which virulence factor produced by Actinobacillus actinomycetemcomitans allows the bacterium to evade the host immune system by killing white blood cells. A. leukotoxin B. hemagglutinin C. LPS D. capsule

11??

______50. The bacterium that causes 90% of localized juvenile periodontitis is: A. Porphyromonas gingivalis B. Prevotella intermedia C. Actinobacillus actinomycetemcomitans D. Campylobacter rectus

______51. The bacterium that causes 80% of adult periodontitis is: A. Porphyromonas gingivalis B. Prevotella intermedia C. Actinobacillus actinomycetemcomitans D. Campylobacter rectus

______52. The bacteria associated with Adult Necrotizing Ulcerative Gingivitis are: A. Porphyromonas gingivalis and Prevotella intermedia B. Peptococcus and C. spirochetes and Prevotella intermedia D. Prevotella buccae and Capnocytophaga gingivalis

______53. This virulence factor, which is elaborated by most of the important periodontal and endodontic pathogens, can induce tissue destruction and bone resorption through activation of the host's macrophages and monocytes. A. leukotoxin B. hemagglutinin C. LPS D. capsule

______54. The most common means through which bacteria gain access to the dentinal tubules and thereby produce inflammation and infection in the dental pulp is: A. periodontal treatment B. mechanical exposure due to operative procedures C. trauma D. caries

12?? ______55. Under what conditions might an infected pulp be a source of periapical infection or inflammation? A. Bacteria and bacterial toxins in the infected pulp may move out through the lateral canals or the apical foramina. B. Periodontal treatment may denude dentin to dentinal tubules. C. Plaque involved in periodontal disease may cover the entire length of the root and reach the apical vessels. D. Anaerobic bacteria at the base of carious lesions may invade the dentinal tubules. ______56. Which of the following bacteria is known to invade tissue? A. Treponema denticola B. Eubacterium spp. C. Prevotella intermedia D. Peptostreptococcus spp.

______57. The BPB that is most frequently isolated from root canals is: A. Porphyromonas endodontalis B. Eubacterium spp. C. Prevotella intermedia D. Peptostreptococcus spp.

______58. The BPB that is most often isolated from infected pulp with acute apical abscess A. Porphyromonas endodontalis B. Porphyromonas gingivalis C. Prevotella intermedia D. A and B

______59. The BPB that is most often associated with pregnancy gingivitis: A. Porphyromonas endodontalis B. Porphyromonas gingivalis C. Prevotella intermedia D. A and B

______60. Which of the following bacteria are rarely found in endodontic lesions? A. Peptococcus spp. B. Peptostreptococcus spp. C. Propionibacterium spp. D. spirochetes

13??

______61. You suffer a sharps injury in your dental operatory from a needle you have used on a patient that you know is at high risk for hepatitis B. Assuming you want to live a long healthy life and continue in the dental profession, what outcome would you hope to hear regarding your patient's serological status. A. Your patient's serum tests positive for the HBsAg and has low levels of IgM antibody to the HBsAg B. Your patient has extremely high levels of anti-HBs (IgG antibody) in the absence of the HBsAg C. Your patient tests positive for anti-HBc in the absence of anti-HBs D. Your patient tests positive for the HBeAg

_____ 62. The clinical group of HIV patients which may transmit the HIV virus and yet be seronegative for the viral antibody are: A. Group 4, AIDS patients B. Group 3, advanced HIV symptoms C. Group 2, asymptomatic D. Group 1, acute HIV infection

_____ 63. What is not characteristic of retroviruses? A. reverse transcriptase B. oncogenic C. leukemia virus D. integrase is an important viral enzyme E. DNA virus

______64. What virus crosses the placenta and causes congenital birth defects? A. measles B. rubella C. varicella D. cytomegalovirus E. herpes simplex

______65. This is a serious complication of infection with the influenzae virus and causes neurologic and metabolic diseases of children:

14?? A. primary viral pneumoniae B. shingles C. Reye's syndrome D. Subacute sclerosing pan encephalitis (SSPE)

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