Question 1

Which of the following statements about staphylococcal enterotoxin is FALSE?

Accepted Answer

A)   It is a superantigen.
B)   It is produced by Staphylococcus aureus growing in the hostʹs intestines.
C)   It causes vomiting.
D)   It causes diarrhea.
E)   It is an exotoxin. B

Question 2

The Limulus amoebocyte assay is used to detect minute amounts of endotoxin in drugs and medical devices.

Accepted Answer

A) True 
 B)False

Question 3

All of the following contribute to a pathogenʹs invasiveness EXCEPT

Accepted Answer

A)   capsules.
B)   toxins.
C)   hyaluronidase.
D)   coagulases.
E)   cell wall components.

Question 4

All of the following bacteria release endotoxin EXCEPT

Accepted Answer

A)   Proteus vulgaris.
B)   Clostridium botulinum.
C)   Salmonella typhi.
D)   Neisseria meningitidis.
E)   Haemophilus influenzae.

Question 5

Which of the following is NOT a cytopathic effect of viruses?

Accepted Answer

A)   host cells fusing to form multinucleated syncytia
B)   inclusion bodies forming in the cytoplasm or nucleus
C)   toxin production
D)   increased cell growth
E)   cell death

Question 6

Which of the following mechanisms is used by gram -negative bacteria to cross the blood-brain barrier?

Accepted Answer

A)   producing toxins
B)   inducing endocytosis
C)   producing fimbriae
D)   antigenic variation
E)   inducing TNF

Question 7

Compare and contrast endotoxins and exotoxins. Why are exotoxins more potent than endotoxins?

Accepted Answer

Endotoxins and exotoxins are both types ...

Question 8

In general, the LD50 for exotoxins is much greater than the LD50 for endotoxins.

Accepted Answer

A) True 
 B)False

Question 9

Cytopathic effects, such as inclusion bodies and syncytium formation, are the visible signs of viral infections.

Accepted Answer

A) True 
 B)False

Question 10

Antibiotics can kill gram-negative bacteria, but symptoms of fever and low blood pressure can persist. Why?

Accepted Answer

Antibiotics can effectively kill gram-ne...

Question 11

Endotoxins are

Accepted Answer

A)   A-B toxins.
B)   associated with gram-positive bacteria.
C)   part of the gram-negative cell wall.
D)   excreted from the cell.
E)   molecules that bind nerve cells.

Question 12

Injectable drugs are tested for endotoxins by

Accepted Answer

A)   culturing bacteria.
B)   the Limulus amoebocyte lysate test.
C)   filtering out the cells.
D)   looking for turbidity.
E)   counting the viable bacteria.

Question 13

Which of the following statements about M protein is FALSE?

Accepted Answer

A)   It is found on Streptococcus pyogenes.
B)   It is heat- and acid-resistant.
C)   It is a protein.
D)   It is found on fimbriae.
E)   It is readily digested by phagocytes.

Question 14

All of the following are used by bacteria to attach to host cells EXCEPT

Accepted Answer

A)   A-B toxins.
B)   M protein.
C)   ligands.
D)   capsules.
E)   fimbriae.

Question 15

The ability of some microbes, such as Trypanosoma or Giardia to alter their surface molecules and evade destruction by the hostʹs antibodies is called

Accepted Answer

A)   cytocidal effect.
B)   antigenic variation.
C)   virulence.
D)   lysogenic conversion.
E)   cytopathic effect.

Question 16

All of the following are methods of avoiding host antibodies EXCEPT

Accepted Answer

A)   membrane-disrupting toxins.
B)   antigenic changes.
C)   inducing endocytosis.
D)   IgA proteases.
E)   invasins. A

Question 17

Ergot and aflatoxin are toxins sometimes found in grains contaminated with fungi.

Accepted Answer

A) True 
 B)False

Question 18

Which of the following does NOT contribute to the symptoms of a fungal disease?

Accepted Answer

A)   capsules
B)   metabolic products
C)   cell walls
D)   allergic response of the host
E)   toxins

Question 19

Nonpathogenic Vibrio cholerae can acquire the cholera toxin gene by

Accepted Answer

A)   infecting a pathogenic Vibrio cholerae.
B)   transduction.
C)   transformation.
D)   conjugation.
E)   phagocytosis. B

Question 20

Cytopathic effects are changes in host cells due to

Accepted Answer

A)   viral infections.
B)   helminthic infections.
C)   protozoan infections.
D)   fungal infections.
E)   bacterial infections.

Exam 15: Microbial Mechanisms of Pathogenicity

Which of the following statements about staphylococcal enterotoxin is FALSE?

Correct AnswerverifiedB

The Limulus amoebocyte assay is used to detect minute amounts of endotoxin in drugs and medical devices.

Correct AnswerverifiedShow Answer

All of the following contribute to a pathogenʹs invasiveness EXCEPT

Correct AnswerverifiedShow Answer

All of the following bacteria release endotoxin EXCEPT

Correct AnswerverifiedShow Answer

Which of the following is NOT a cytopathic effect of viruses?

Correct AnswerverifiedShow Answer

Which of the following mechanisms is used by gram -negative bacteria to cross the blood-brain barrier?

Correct AnswerverifiedShow Answer

Compare and contrast endotoxins and exotoxins. Why are exotoxins more potent than endotoxins?

Correct AnswerAnswered by ExamLex AIEndotoxins and exotoxins are both types ...View AnswerShow Answer

In general, the LD50 for exotoxins is much greater than the LD50 for endotoxins.

Correct AnswerverifiedShow Answer

Cytopathic effects, such as inclusion bodies and syncytium formation, are the visible signs of viral infections.

Correct AnswerverifiedShow Answer

Antibiotics can kill gram-negative bacteria, but symptoms of fever and low blood pressure can persist. Why?

Correct AnswerAnswered by ExamLex AIAntibiotics can effectively kill gram-ne...View AnswerShow Answer

Endotoxins are

Correct AnswerverifiedShow Answer

Injectable drugs are tested for endotoxins by

Correct AnswerverifiedShow Answer

Which of the following statements about M protein is FALSE?

Correct AnswerverifiedShow Answer

All of the following are used by bacteria to attach to host cells EXCEPT

Correct AnswerverifiedShow Answer

The ability of some microbes, such as Trypanosoma or Giardia to alter their surface molecules and evade destruction by the hostʹs antibodies is called

Correct AnswerverifiedShow Answer

All of the following are methods of avoiding host antibodies EXCEPT

Correct AnswerverifiedA

Ergot and aflatoxin are toxins sometimes found in grains contaminated with fungi.

Correct AnswerverifiedShow Answer

Which of the following does NOT contribute to the symptoms of a fungal disease?

Correct AnswerverifiedShow Answer

Nonpathogenic Vibrio cholerae can acquire the cholera toxin gene by

Correct AnswerverifiedB

Cytopathic effects are changes in host cells due to

Correct AnswerverifiedShow Answer

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B

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Answered by ExamLex AI
Endotoxins and exotoxins are both types ...
View Answer

Correct Answer
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Correct Answer
Answered by ExamLex AI
Antibiotics can effectively kill gram-ne...
View Answer

Correct Answer
verified

Correct Answer
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A

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B

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