BioSc221/325 Exam 4 WS2000 Name ______________________________Multiple choice. (1 point each) Choose the one best answer to each of the following questions.1. _C_Which of the following areas of the body do not have a resident microbial flora?A. upper respiratory tractB. eyesC. bladderD. ear2. _D_ Which statement(s) is/are true?A. Gram positive organisms dominate the microflora.B. Propionibacterium acnes is a normal resident of the skin.C. Lipophilic yeasts are sometimes normal residents of the skin.D. All of the above3. _D_ Which of the following phenomena is/are associated with the metabolic and biochemical activities of the intestinalmicroflora?A. Vitamin synthesisB. Production of aminesC. Production of organic acidsD. All of the above.4. _C_ Which of the following organisms is most likely to be implicated in dental caries?A. Staphylococcus aureusB. Staphylococcus epidermidisC. Streptococcus sobrinusD. Escherichia coli5. _B_ Which statement is true about an exotoxin?A. It is mostly produced by gram negative bacteria.B. Its LD50 may be as low as the picogram level.C. It is composed primarily of carbohydrate.D. It is LPS associated.6. _B_ Gingivitis is a(n)A. early form of bone loss.B. inflammation of the soft tissue.C. periodontal disease.D. all of the above.7. _A_ Which of the following is an enterotoxin?A. Cholera toxinB. Diphtheria toxinC. Plague toxinD. LPS of Salmonella8. _B_ Which exotoxin binds to inhibitory neurons, blocking the release of glycine, and resulting in twitching paralysis?A. Diphtheria toxinB. Tetanus toxinC. Botulinum toxinD. Cholera toxin9. _A_ Which of the following is/are associated with bacterial invasion?A. CollagenaseB. PhospholipaseC. HemolysinD. All of the above10. _D_ The toxin of Clostridium tetani is classified as a(n)A. EndotoxinB. CytotoxinC. EnterotoxinD. Neurotoxin11. _B_ The substance in the LPS for gram negative bacteria that is responsible for the effects of the toxin isA. The core polysaccharideB. Lipid AC. The O-polysaccharideD. the dideoxysugars12. _A_ Antibacterial substances found in the mouth includeA. LysozymeB. LysozomeC. LipaseD. All of the above13. _A_ Hemolysins are lytic agents thatA. lyse red blood cellsB. lyse white blood cellsC. lyse bacterial cellsD. destroy viruses14. _A_ Which of the following virulence factors are important for pathogenicity in Streptococcus pneumoniae?A. capsuleB. exotoxin PC. hemolysinD. all of the above15. _C_ The most common of all nosocomial infections are found in theA. bloodB. reproductive tractC. urinary tractD. respiratory tract16. _C_ MacConkey's agar and EMB agar areA. selective but not differentialB. differential but not selectiveC. both selective and differentialD. neither selective nor differential17. _A_ Which of the following tests would allow the specific identification of a single microbe under the microscope?A. fluorescent antibody (FA)B. radioimmunoassay (RIA)C. enzyme-linked immunosorbent assay (ELISA)D. agglutination.18. _B_ In which type of medium will an indicator dye be found?A. selective but not differentialB. differential but not selectiveC. both selective and differentialD. neither selective nor differential19. _C_ Transmission of an infectious disease is most likely during theA. incubation periodB. prodromal periodC. acute periodD. decline period20. _B_ Diseases that naturally occur in animals and accidentally in humans are calledA. nosocomial infectionsB. zoonosisC. vector infectionsD. muduranes21. _A_ An inanimate object that transmits infectious agents between hosts is most appropriately called aA. fomiteB. carrierC. vectorD. reservoir22. _C_ A tick transmitting Rickettsia rickettsii to a human is an example of a(n)A. endemic vectorB. opportunistic pathogenC. biological vectorD. mechanical vector23. _A_ According to recent statistical studies in the US, a person is most apt to acquire a serious infectionA. in a hospitalB. at homeC. At schoolD. While travelling24. _C_ The federal agency responsible for disease surveillance in the US is theA. USDAB. FDAC. CDCD. EPA25. _A_ Which of the following diseases would not normally be spread by a common source?A. measlesB. typhoid feverC. dysenteryD. cholera26. _D_ Which of the following is/are considered direct contact infections?A. syphilisB. gonorrheaC. AIDSD. all of the aboveShort answer. (1 or 2 points each)(1) The relative ability of a pathogen to cause disease of greater or lesser severity is that pathogen's __Virulence__.(1) When the virulence of a pathogen is decreased of even completely lost, the pathogen is said to be __Attenuated__ .(1) A polymer coat consisting of a dense, well-defined layer closely surrounding the cell is known as the __Capsule__.(1) A large number of bacteria in the bloodstream results in a condition known as __Bacteremia__.(1) Describe one of the properties of microorganisms that grow well on the skin.Salt tolerant, Acid tolerant, etc(1) Why are hospital patients more susceptible than "normal" individuals to infectious agents?They are often immunocompromised.(1) Why does Lactobacillus inhabit the stomach?Lactobacilli are acid tolerant.(2) What are the four possible outcomes resulting from the initial contact with a microbe?Colonization. Infection, Loss, Alergy(1) What is an infectious dose?The number of bacteria that will produce disease in 50% of the hosts receiving that dose.(2) Describe the stages of infection and what is happening in each stage.Incubation period - bacteria are attaching and multiplying in the hostProdromium - bacteria have reached sufficient number to illicit the first signs and symptoms of illness.Period of Invasion (Height of infection)(Fastidium) - bacteria are exerting their maximal effect on the hostConvalescent period - the host begins to recover, signs and symptoms subside, bacterial number decreases, antibodytiter continues to increase(1) Why do Gram-positive Bacteria not produce endotoxins?They don't have an outer membrane containing Lipid A.(1) Why are the endotoxins generally not as potent as the exotoxins?Endotoxins elicit a general response whereas exotoxins target a specific cell or tissue type.(2) Describe two of the three types of fever.Continuous - fever remains high (not fluctuating more than 1 degree) for a 24 hour period.Intermittent - fever is constant for 24 hours but fluctuates by more than 1 degree during that period.Recurrent - fever subsides within 24 hours but returns(1) How might preexisting infections compromise an otherwise healthy