Question 1

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

Question 2

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

Question 3

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. 
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 4

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

Accepted Answer

A) True 
 B)False

Question 5

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

Question 6

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

Question 7

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

Accepted Answer

A) True 
 B)False

Question 8

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

Question 9

All of the following contribute to a pathogenʹs invasiveness EXCEPT

Accepted Answer

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

Question 10

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

Accepted Answer

A) True 
 B)False

Question 11

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 
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 12

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. 
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 13

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

Question 14

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

Accepted Answer

A) True 
 B)False

Question 15

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

Question 16

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

Question 17

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 18

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. 
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 19

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

Question 20

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

Accepted Answer

Endotoxins and exotoxins are both types

Exam 15: Microbial Mechanisms of Pathogenicity

All of the following are methods of avoiding host antibodies EXCEPT

Nonpathogenic Vibrio cholerae can acquire the cholera toxin gene by

Which of the following statements about staphylococcal enterotoxin is FALSE?

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

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

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

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

Cytopathic effects are changes in host cells due to

All of the following contribute to a pathogenʹs invasiveness EXCEPT

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

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

Endotoxins are

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

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

All of the following bacteria release endotoxin EXCEPT

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

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

Which of the following statements about M protein is FALSE?

Injectable drugs are tested for endotoxins by

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

The Microbial World and You

Chemical Principles

Observing Microorganisms Through a Microscope

Functional Anatomy of Prokaryotic and Eukaryotic Cells

Microbial Metabolism

Microbial Growth

The Control of Microbial Growth

Microbial Genetics

Biotechnology and Dna Technology

Classification of Microorganisms

The Prokaryotes: Domains Bacteria and Archaea

The Eukaryotes: Fungi, Algae, Protozoa, and Helminths

Viruses, Viroids, and Prions

Principles of Disease and Epidemiology

Innate Immunity: Nonspecific Defenses of the Host

Adaptive Immunity: Specific Defenses of the Host

Practical Applications of Immunology

Disorders Associated With the Immune System

Antimicrobial Drugs

Microbial Diseases of the Skin and Eyes

Microbial Diseases of the Nervous System

Microbial Diseases of the Cardiovascular and Lymphatic Systems

Microbial Diseases of the Respiratory System

Microbial Diseases of the Digestive System

Microbial Disease of the Urinary and Reproductive Systems

Environmental Microbiology

Applied and Industrial Microbiology

Filters