Question 1

Dissemination of a pathogen is when:

Accepted Answer

A)  a pathogen penetrates and grows in tissues.
B)  a pathogen multiplies intracellularly.
C)  a pathogen circumvents host antibodies by shifting key cell-surface antigens.
D)  infection with a pathogen spreads from the initial infection site to distant sites such as organs and tissues.E) A) and B)
F) B) and C)

Question 2

Diabetics may sometimes be infected with their own resident flora.This type of infection is called:

Accepted Answer

A)  an opportunistic infection.
B)  a carrier state.
C)  symbiosis.
D)  a parasitic infection.E) All of the above
F) C) and D)

Question 3

Factors that determine the pathogenicity and increase the virulence of organisms include all the following except an organism's ability to:

Accepted Answer

A)  avoid phagocytosis.
B)  produce exotoxins and extracellular enzymes.
C)  produce infection when host conditions change.
D)  survive intracellularly when phagocytized.E) A) and D)
F) A) and B)

Question 4

Mechanisms used by the skin to prevent infection and protect the underlying tissue from invasion by potential pathogens include all the following except:

Accepted Answer

A)  desquamation of the epithelium.
B)  excretion of lysozyme by sweat glands.
C)  antibiotics that inhibit many microorganisms.
D)  mechanical separation of microorganisms from the tissues.E) C) and D)
F) B) and C)

Question 5

One of the most effective defenses bacteria have against phagocytosis is:

Accepted Answer

A)  enzymes.
B)  the capsule.
C)  plasmids.
D)  lipopolysaccharide layer.E) None of the above
F) C) and D)

Question 6

The human body is constantly challenged by pathogens in the environment.It is not infected by every pathogen it encounters because the microbial flora:

Accepted Answer

A)  engulf the pathogenic bacteria.
B)  produce conditions at the microenvironmental level that block colonization.
C)  prime our immune system.
D)  activate and support the action of antigen-presenting cells, cytokines, and cell-mediated immunity.E) All of the above
F) None of the above

Question 7

Healthy skin secretes what substances to help prevent colonization by transient and possibly pathogenic organisms?

Accepted Answer

A)  Long-chain fatty acids
B)  Sebaceous glands
C)  Carbohydrates
D)  AntibodiesE) A) and B)
F) B) and C)

Question 8

After perforation of the colon, surgeons must guard against infection in the _____ because of leakage of the contents of the colon.

Accepted Answer

A)  peritoneal cavity
B)  urinary bladder
C)  vaginal flora
D)  renal veinE) B) and D)
F) A) and D)

Question 9

The classic example of a bite-wound infection is:

Accepted Answer

A)  rabies.
B)  S.aureus.
C)  plague.
D)  Ebola.E) A) and B)
F) B) and D)

Question 10

All the following are potentially pathogenic organisms found in the nasopharynx of healthy individuals except:

Accepted Answer

A)  Haemophilus influenzae.
B)  Streptococcus pneumoniae.
C)  Streptococcus mutans.
D)  Neisseria meningitidis.E) None of the above
F) B) and C)

Question 11

What is the name of a leukocidin that is lethal to leukocytes and produced by staphylococci?

Accepted Answer

A)  Panton-Valentine
B)  Lancefield
C)  Hemolysin
D)  AdhesinsE) A) and D)
F) A) and B) A

Question 12

Changes in what host structures can result in lower virulence of a microorganism?

Accepted Answer

A)  Pili
B)  Adhesin receptors
C)  Surface polysaccharides
D)  PhagocytesE) B) and D)
F) B) and C) B

Question 13

During the childbearing years, the normal flora of the vagina maintain a low pH, thus encouraging colonization with all the following types of organisms except:

Accepted Answer

A)  lactobacilli.
B)  gram-negative rods.
C)  anaerobic gram-negative bacilli.
D)  gram-positive cocci.E) None of the above
F) All of the above

Question 14

Organisms that participate in a biologic relationship where both benefit from one another are called:

Accepted Answer

A)  parasites.
B)  symbionts.
C)  hosts.
D)  flora.E) A) and B)
F) A) and D) B

Question 15

A physician notices that several patients are infected with Clostridium difficile, but only a few of the patients are symptomatic for disease.The reason for this discrepancy is:

Accepted Answer

A)  only those strains of the organism carrying the extrachromosomal DNA coding for the toxin gene will produce toxin and cause the individuals to be symptomatic.
B)  only those strains of the organism carrying DNA coding for the toxin within its main DNA molecule will produce toxin and cause the individuals to be symptomatic.
C)  the exotoxin produced contains only the nontoxic portion.
D)  the exotoxin must be produced in conjunction with extracellular enzymes to cause problems.E) None of the above
F) B) and C)

Question 16

What virus causes immune suppression in the host by targeting and destroying the host's CD4+ T cells?

Accepted Answer

A)  HIV
B)  Hepatitis B
C)  Epstein-Barr
D)  CytomegalovirusE) A) and B)
F) None of the above

Question 17

Because infections can be encountered via the air, _____ can cause transmission of some pathogens.

Accepted Answer

A)  cuts
B)  eyes
C)  coughing
D)  eatingE) All of the above
F) None of the above

Question 18

What type of bacteria is able to live in the colon with little to no oxygen and is the predominant organism?

Accepted Answer

A)  Anaerobes
B)  Facultative anaerobes
C)  Facultative gram-negative rods
D)  Gram-positive cocciE) B) and C)
F) C) and D)

Question 19

What mechanism allows strict anaerobes to grow in the cervices and areas between the teeth when plaque is present?

Accepted Answer

A)  A low oxidation-reduction potential occurs at the tooth surface under the plaque.
B)  The bacteria secrete sugar to nourish the strict anaerobes.
C)  The normal flora secrete antibiotics to kill all the other bacteria and allow the strict anaerobes to thrive.
D)  The plaque-causing bacteria secrete an alkaline fluid and change the pH around the tooth.E) All of the above
F) A) and C)

Question 20

The stomach can be considered a first line of defense against microbial infections because:

Accepted Answer

A)  most microorganisms are susceptible to the antibiotics and alkaline pH present in the stomach.
B)  most microorganisms are killed by the liver enzymes that are emptied into the stomach during a meal.
C)  the stomach produces proteases, which attacks the lipopolysaccharide cell wall of the organisms.
D)  most microorganisms are susceptible to the acid pH of the stomach.E) None of the above
F) A) and B)

Exam 2: Host-Parasite Interaction

Dissemination of a pathogen is when:

Correct AnswerverifiedShow Answer

Diabetics may sometimes be infected with their own resident flora.This type of infection is called:

Correct AnswerverifiedShow Answer

Factors that determine the pathogenicity and increase the virulence of organisms include all the following except an organism's ability to:

Correct AnswerverifiedShow Answer

Mechanisms used by the skin to prevent infection and protect the underlying tissue from invasion by potential pathogens include all the following except:

Correct AnswerverifiedShow Answer

One of the most effective defenses bacteria have against phagocytosis is:

Correct AnswerverifiedShow Answer

The human body is constantly challenged by pathogens in the environment.It is not infected by every pathogen it encounters because the microbial flora:

Correct AnswerverifiedShow Answer

Healthy skin secretes what substances to help prevent colonization by transient and possibly pathogenic organisms?

Correct AnswerverifiedShow Answer

After perforation of the colon, surgeons must guard against infection in the _____ because of leakage of the contents of the colon.

Correct AnswerverifiedShow Answer

The classic example of a bite-wound infection is:

Correct AnswerverifiedShow Answer

All the following are potentially pathogenic organisms found in the nasopharynx of healthy individuals except:

Correct AnswerverifiedShow Answer

What is the name of a leukocidin that is lethal to leukocytes and produced by staphylococci?

Correct AnswerverifiedA

Changes in what host structures can result in lower virulence of a microorganism?

Correct AnswerverifiedB

During the childbearing years, the normal flora of the vagina maintain a low pH, thus encouraging colonization with all the following types of organisms except:

Correct AnswerverifiedShow Answer

Organisms that participate in a biologic relationship where both benefit from one another are called:

Correct AnswerverifiedB

A physician notices that several patients are infected with Clostridium difficile, but only a few of the patients are symptomatic for disease.The reason for this discrepancy is:

Correct AnswerverifiedShow Answer

What virus causes immune suppression in the host by targeting and destroying the host's CD4+ T cells?

Correct AnswerverifiedShow Answer

Because infections can be encountered via the air, _____ can cause transmission of some pathogens.

Correct AnswerverifiedShow Answer

What type of bacteria is able to live in the colon with little to no oxygen and is the predominant organism?

Correct AnswerverifiedShow Answer

What mechanism allows strict anaerobes to grow in the cervices and areas between the teeth when plaque is present?

Correct AnswerverifiedShow Answer

The stomach can be considered a first line of defense against microbial infections because:

Correct AnswerverifiedShow Answer

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