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Koch's Postulates quiz #1

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  • Which of the following is NOT a verified exception to Koch's postulates?
    A microbe that can be grown in pure culture is NOT a verified exception; verified exceptions include microbes that cannot be cultured outside host cells (e.g., obligate intracellular pathogens), asymptomatic infections, and ethical limitations in testing.
  • In which of the following situations would Koch's postulates be utilized?
    Koch's postulates would be utilized when determining whether a specific microbe is the cause of a particular disease.
  • Order the four steps of Koch's postulates as they would normally be applied.
    1) The microbe must be present in every case of the disease; 2) The microbe must be isolated and grown in pure culture; 3) The same disease must occur when the pure culture is introduced into a susceptible host; 4) The microbe must be isolated from the experimentally infected host.
  • When would Koch's postulates be utilized?
    Koch's postulates are used when scientists need to establish a causal relationship between a microbe and a specific disease.
  • Koch's postulates are criteria used to establish that:
    A specific microbe is the cause of a particular disease.
  • Which bacterium did Robert Koch identify as the cause of anthrax using his postulates?
    Robert Koch identified Bacillus anthracis as the cause of anthrax using his postulates.
  • Why can't all pathogenic microbes be grown in pure culture according to Koch's postulates?
    Some pathogenic microbes, such as obligate intracellular pathogens, require host cells to grow and cannot be cultured on standard laboratory media.
  • What is a pure culture in the context of Koch's postulates?
    A pure culture is a laboratory culture that contains only one single species of microbe, isolated from the diseased host.
  • How can variability in immune responses among individuals limit the application of Koch's postulates?
    Variability in immune responses can result in some infected individuals not showing symptoms, making it difficult to link the microbe to the disease in every case.
  • What ethical issue can arise when applying the fourth of Koch's postulates to human diseases?
    Testing on humans or animals to isolate the microbe from experimentally infected hosts raises ethical and safety concerns, limiting the reliability of results.