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MCB4403 Exam #4 Study Guide.
Pathogenicity - Answers✔the ability to cause disease
Pathogen - Answers✔An organism that causes disease
Virulence - Answers✔the degree of pathogenicity
Virulence factors - Answers✔traits of a microbe that promote pathogenicity
Pathology - Answers✔the study of disease
Etiology - Answers✔The study of the cause of disease
Pathogenesis - Answers✔the development of disease
Infection - Answers✔the growing and multiplying of pathogens in the host
Disease - Answers✔an abnormal state in which the body is not functioning normally.
T/F: Infection always leads to disease - Answers✔False. Most infections are removed by the
immune system.
________ have the ability to penetrate host defenses. - Answers✔Primary pathogens
_________ cause disease only in compromised hosts. - Answers✔Opportunistic pathogens
What does "ID50" stand for? - Answers✔Infectious dose of 50% of the test population
What ID50 value would be the most virulent? - Answers✔The smaller value, because it requires
a lower to dose to infect the same amount of people.
What does "LD50" stand for? - Answers✔Lethal dose of a toxin for 50% of the test population
What LD50 value would be most virulent? - Answers✔The smaller value, because it requires a
lower to dose to kill the same amount of people.
_______ are considered a _______ of infection because they may have inapparent infections or
latent disease. - Answers✔Carriers; reservoir
A pathogen of _________ origin is one that mutated from an animal. - Answers✔zoonotic
Give an example of a human reservoir of infection pathogen - Answers✔STDs
1
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Give an example of an animal reservoir of infection pathogen - Answers✔rabies, lyme disease
Give an example of a nonliving reservoir of infection pathogen - Answers✔botulism, tetanus,
anthrax
What would be a common nonliving reservoir of infection? - Answers✔Soil
What are the three portals of entry? (that's what she said) - Answers✔skin, mucous membrane,
parenteral route
What is meant by the parenteral route of infection? - Answers✔entering the blood stream
through injection such as needles, mosquitos, and ticks
Vehicle transmission is through _______ - Answers✔an inanimate reservoir, for example, food
or water.
Vector disease transmission occurs from _______ - Answers✔an animal host to human host
Mechanical vector disease transmission occurs when _____ - Answers✔an arthropods carries
pathogens on their feet, such as flies carrying typhoid fever.
Biological vector disease transmission occurs when _______ - Answers✔the pathogen
reproduces within the vector, for example, lyme disease in ticks.
_______ contact transmission requires close associate between the infected host and susceptible
host (ex. touching). - Answers✔Direct
_______ contact transmission requires contact with fomites (ex. a cup). - Answers✔Indirect
_______ contact transmission is airborne (ex. coughing). - Answers✔Droplet
In ______ disease, symptoms develop rapidly. - Answers✔acute
In ______ disease, symptoms develop slowly. - Answers✔chronic
In ______ disease, symptoms develop between acute and chronic. - Answers✔subacute
In ______ disease, the disease displays no symptoms for a period of inactivity. - Answers✔latent
Give an example of a latent virus - Answers✔Herpesvirus
To cause disease, all pathogens must: - Answers✔1. enter a host
2. find their unique niche
3. evade immune defenses
4. multiply and eventually be transmitted to a new susceptible host
2
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Pathogens can be distinguished from their avirulent counterparts by the presence of their
_________ that help accomplish these goals. - Answers✔virulence factors.
What are Falkow's "Molecular Koch Postulates"? - Answers✔1. The phenotype must match the
pathogenic strains of a species
2. Specific inactivation of a suspected virulence factor should lead to a measurable loss in
virulence
3. Reversion or replacement of the mutated gene should restore pathogenicity
Virulence genes may be found on ____________________ in the chromosome, on plasmids, or
even on phage genomes. - Answers✔pathogenicity islands
Pathogenicity islands contain clusters of virulence genes that were originally inherited through
____________________ - Answers✔horizontal transmission
Pathogenicity islands are often flanked by ______ or ______ genes and have a _______ content
that differs from the rest of the genome. - Answers✔phage; plasmid; GC
The first step of infection is ___________. - Answers✔attachment/adhesion
Bacteria attach to a host cell with _____ or _______ - Answers✔pili; adhesins
Adhesins are - Answers✔surface proteins that bind to a host cell
Viruses attach to their hosts through their ________ - Answers✔capsid or envelope proteins
Bacteria can attach to surfaces in bulk, forming a _________ - Answers✔biofilm
How biofilms participate in chronic infections? - Answers✔They enable a persistent adherence
and resistance to the host and antimicrobial agents.
A ______ is a substance that contributes to pathogenicity - Answers✔toxin
A _______ is an inactivated toxin used in vaccines - Answers✔toxoid
An ________ is an antibody against a specific toxin - Answers✔antitoxin
What are the two main types of bacterial toxins? - Answers✔exotoxins and endotoxins
Exotoxins are _______ produces by bacteria to _______ host cells and unlock their _______ -
Answers✔proteins; kill; nutrients
Endotoxins are part of the ______ of Gram-_______ bacteria that ________ the host's immune
systems to harmful levels. - Answers✔LPS; negative; hyperactivate
Membrane-disrupting toxins can be either _______ (lyse RED blood cells) or _______ (lyse
WHITE blood cells) - Answers✔hemolysins; leukocidins
3
MCB4403 Exam #4 Study Guide.
Pathogenicity - Answers✔the ability to cause disease
Pathogen - Answers✔An organism that causes disease
Virulence - Answers✔the degree of pathogenicity
Virulence factors - Answers✔traits of a microbe that promote pathogenicity
Pathology - Answers✔the study of disease
Etiology - Answers✔The study of the cause of disease
Pathogenesis - Answers✔the development of disease
Infection - Answers✔the growing and multiplying of pathogens in the host
Disease - Answers✔an abnormal state in which the body is not functioning normally.
T/F: Infection always leads to disease - Answers✔False. Most infections are removed by the
immune system.
________ have the ability to penetrate host defenses. - Answers✔Primary pathogens
_________ cause disease only in compromised hosts. - Answers✔Opportunistic pathogens
What does "ID50" stand for? - Answers✔Infectious dose of 50% of the test population
What ID50 value would be the most virulent? - Answers✔The smaller value, because it requires
a lower to dose to infect the same amount of people.
What does "LD50" stand for? - Answers✔Lethal dose of a toxin for 50% of the test population
What LD50 value would be most virulent? - Answers✔The smaller value, because it requires a
lower to dose to kill the same amount of people.
_______ are considered a _______ of infection because they may have inapparent infections or
latent disease. - Answers✔Carriers; reservoir
A pathogen of _________ origin is one that mutated from an animal. - Answers✔zoonotic
Give an example of a human reservoir of infection pathogen - Answers✔STDs
1
, ©FYNDLAY.
Give an example of an animal reservoir of infection pathogen - Answers✔rabies, lyme disease
Give an example of a nonliving reservoir of infection pathogen - Answers✔botulism, tetanus,
anthrax
What would be a common nonliving reservoir of infection? - Answers✔Soil
What are the three portals of entry? (that's what she said) - Answers✔skin, mucous membrane,
parenteral route
What is meant by the parenteral route of infection? - Answers✔entering the blood stream
through injection such as needles, mosquitos, and ticks
Vehicle transmission is through _______ - Answers✔an inanimate reservoir, for example, food
or water.
Vector disease transmission occurs from _______ - Answers✔an animal host to human host
Mechanical vector disease transmission occurs when _____ - Answers✔an arthropods carries
pathogens on their feet, such as flies carrying typhoid fever.
Biological vector disease transmission occurs when _______ - Answers✔the pathogen
reproduces within the vector, for example, lyme disease in ticks.
_______ contact transmission requires close associate between the infected host and susceptible
host (ex. touching). - Answers✔Direct
_______ contact transmission requires contact with fomites (ex. a cup). - Answers✔Indirect
_______ contact transmission is airborne (ex. coughing). - Answers✔Droplet
In ______ disease, symptoms develop rapidly. - Answers✔acute
In ______ disease, symptoms develop slowly. - Answers✔chronic
In ______ disease, symptoms develop between acute and chronic. - Answers✔subacute
In ______ disease, the disease displays no symptoms for a period of inactivity. - Answers✔latent
Give an example of a latent virus - Answers✔Herpesvirus
To cause disease, all pathogens must: - Answers✔1. enter a host
2. find their unique niche
3. evade immune defenses
4. multiply and eventually be transmitted to a new susceptible host
2
, ©FYNDLAY.
Pathogens can be distinguished from their avirulent counterparts by the presence of their
_________ that help accomplish these goals. - Answers✔virulence factors.
What are Falkow's "Molecular Koch Postulates"? - Answers✔1. The phenotype must match the
pathogenic strains of a species
2. Specific inactivation of a suspected virulence factor should lead to a measurable loss in
virulence
3. Reversion or replacement of the mutated gene should restore pathogenicity
Virulence genes may be found on ____________________ in the chromosome, on plasmids, or
even on phage genomes. - Answers✔pathogenicity islands
Pathogenicity islands contain clusters of virulence genes that were originally inherited through
____________________ - Answers✔horizontal transmission
Pathogenicity islands are often flanked by ______ or ______ genes and have a _______ content
that differs from the rest of the genome. - Answers✔phage; plasmid; GC
The first step of infection is ___________. - Answers✔attachment/adhesion
Bacteria attach to a host cell with _____ or _______ - Answers✔pili; adhesins
Adhesins are - Answers✔surface proteins that bind to a host cell
Viruses attach to their hosts through their ________ - Answers✔capsid or envelope proteins
Bacteria can attach to surfaces in bulk, forming a _________ - Answers✔biofilm
How biofilms participate in chronic infections? - Answers✔They enable a persistent adherence
and resistance to the host and antimicrobial agents.
A ______ is a substance that contributes to pathogenicity - Answers✔toxin
A _______ is an inactivated toxin used in vaccines - Answers✔toxoid
An ________ is an antibody against a specific toxin - Answers✔antitoxin
What are the two main types of bacterial toxins? - Answers✔exotoxins and endotoxins
Exotoxins are _______ produces by bacteria to _______ host cells and unlock their _______ -
Answers✔proteins; kill; nutrients
Endotoxins are part of the ______ of Gram-_______ bacteria that ________ the host's immune
systems to harmful levels. - Answers✔LPS; negative; hyperactivate
Membrane-disrupting toxins can be either _______ (lyse RED blood cells) or _______ (lyse
WHITE blood cells) - Answers✔hemolysins; leukocidins
3
