Question 1

Briefly describe three classic modes of action of bacterial toxins.

Accepted Answer

Some microbes damage the host membrane b

Question 2

A chef cut his finger accidentally while making salad. The next morning he felt pain and warmth and had a little swelling and redness on that finger (signs of inflammation). By night, he was just fine. Which of the following pertains to the chef?

Accepted Answer

A)  He had an overt microbial disease. 
B)  He had an infection. 
C)  The inflammation was a response to the cut not a microbe. 
D)  Microbial toxins, not the vegetative cells, induced inflammation. 
E)  The cut introduced ectoparasites that could not survive. 
A)  He had an overt microbial disease. 
B)  He had an infection. 
C)  The inflammation was a response to the cut not a microbe. 
D)  Microbial toxins, not the vegetative cells, induced inflammation. 
E)  The cut introduced ectoparasites that could not survive.

Question 3

Describe the deregulation of adenylate cyclase activity by cholera toxin.

Accepted Answer

G-alpha protein is ADP-ribosylated by ch

Question 4

What characteristics of a pathogen distinguish it from a commensal, in terms of its ability to infect and replicate within a eukaryotic host?

Accepted Answer

Commensals are essentially relegated to

Question 5

Which of the following does NOT result from the release of endotoxin from Gram-negative bacteria?

Accepted Answer

A)  fever 
B)  activation of the alternate complement pathway 
C)  vasodilation 
D)  hypertension 
E)  shock 
A)  fever 
B)  activation of the alternate complement pathway 
C)  vasodilation 
D)  hypertension 
E)  shock

Question 6

Which of the following diseases is transmitted by the mosquito, Aedes aegypti?

Accepted Answer

A)  yellow fever 
B)  Ebola 
C)  epidemic typhus 
D)  listeriosis 
E)  SARS 
A)  yellow fever 
B)  Ebola 
C)  epidemic typhus 
D)  listeriosis 
E)  SARS

Question 7

Antigenic shifts and phase variants are important virulence assets for which bacteria?

Accepted Answer

A)  E. coli and Vibrio cholera. 
B)  Clostridium tetani and Bacillus anthracis 
C)  Neisseria gonorrhoeae and Salmonella spp. 
D)  Streptococcus pneumonia and Staphylococcus aureus 
E)  Helicobacter pylori and Enterobacter cloacae 
A)  E. coli and Vibrio cholera. 
B)  Clostridium tetani and Bacillus anthracis 
C)  Neisseria gonorrhoeae and Salmonella spp. 
D)  Streptococcus pneumonia and Staphylococcus aureus 
E)  Helicobacter pylori and Enterobacter cloacae

Question 8

Synthesis of flagella and pili filaments in Gram negatives share which of the following in common?

Accepted Answer

A)  Protein export systems are used to deliver subunits to the outside. 
B)  Chaperons are not needed for protein transport. 
C)  There is no periplasmic stopover. 
D)  Flagellar and pili proteins are added to the base of the structure. 
E)  Flagellar and pili proteins are added to the tip of the structure. 
A)  Protein export systems are used to deliver subunits to the outside. 
B)  Chaperons are not needed for protein transport. 
C)  There is no periplasmic stopover. 
D)  Flagellar and pili proteins are added to the base of the structure. 
E)  Flagellar and pili proteins are added to the tip of the structure.

Question 9

Commensals do not need virulence factors to survive on their host because:

Accepted Answer

A)  they are well adapted for their specific niche 
B)  they do not breach the host barriers and immune system 
C)  they are recognized as self by the host 
D)  two of the above are correct 
E)  all of the above 
A)  they are well adapted for their specific niche 
B)  they do not breach the host barriers and immune system 
C)  they are recognized as self by the host 
D)  two of the above are correct 
E)  all of the above

Question 10

Protein A helps Staphylococcus aureus avoid :

Accepted Answer

A)  complement 
B)  apoptosis 
C)  phagocytosis 
D)  cytotoxic T cells 
E)  phagosome-lysosome fusion 
A)  complement 
B)  apoptosis 
C)  phagocytosis 
D)  cytotoxic T cells 
E)  phagosome-lysosome fusion

Question 11

Superantigens:

Accepted Answer

A)  bore holes on eukaryotic cell membranes 
B)  inhibit phagocytosis 
C)  prevent degranulation of macrophages 
D)  are antipyrogenic 
E)  activate immune cells without being processed 
A)  bore holes on eukaryotic cell membranes 
B)  inhibit phagocytosis 
C)  prevent degranulation of macrophages 
D)  are antipyrogenic 
E)  activate immune cells without being processed

Question 12

Type III and type I pili:

Accepted Answer

A)  are similar to type IV in mode of secretion 
B)  are both mannose-resistant pili 
C)  assembly involves secA general secretory pathway 
D)  are encoded by pathogenicity island 
E)  exclusively used for pathogenesis 
A)  are similar to type IV in mode of secretion 
B)  are both mannose-resistant pili 
C)  assembly involves secA general secretory pathway 
D)  are encoded by pathogenicity island 
E)  exclusively used for pathogenesis

Question 13

Tropheryma whipplei is the causative agent for Whipple's disease. It could not be cultured until recently when the genomic data showed:

Accepted Answer

A)  it was auxotrophic for some amino acids 
B)  that it was an obligate intracellular pathogen 
C)  it needed a helper virus to grow 
D)  that it needed high levels of iron 
E)  that it is a virus that needed cell culture 
A)  it was auxotrophic for some amino acids 
B)  that it was an obligate intracellular pathogen 
C)  it needed a helper virus to grow 
D)  that it needed high levels of iron 
E)  that it is a virus that needed cell culture

Question 14

Which of the following produces a toxin that disrupts protein synthesis?

Accepted Answer

A)  Clostridium perfringens 
B)  Corynebacterium diphtheriae 
C)  Escherichia coli 
D)  Staphylococcus aureus 
E)  Bacillus anthracis 
A)  Clostridium perfringens 
B)  Corynebacterium diphtheriae 
C)  Escherichia coli 
D)  Staphylococcus aureus 
E)  Bacillus anthracis

Question 15

Describe why a blood agar plate can be used to detect the a-hemolytic activity of Staphylococcus aureus.

Accepted Answer

The alpha toxin is secreted by

Question 16

The toxin gene in Corynebacterium diphtheriae is located on __________.

Accepted Answer

A)  plasmid 
B)  mobile genes called transposons 
C)  bacterial chromosomes 
D)  lysogenic phage genomes 
E)  all of the above 
A)  plasmid 
B)  mobile genes called transposons 
C)  bacterial chromosomes 
D)  lysogenic phage genomes 
E)  all of the above

Question 17

Which of the following statements is NOT correct about a patient who died from endotoxin pathologies?

Accepted Answer

A)  Disseminated intravascular coagulation may have contributed to death. 
B)  The MRSA superbug is a likely suspect. 
C)  The patient may have died from hypotension. 
D)  The patient may not have run a fever if AIDS was present. 
E)  The lipid A in the endotoxin is responsible for the virulence. 
A)  Disseminated intravascular coagulation may have contributed to death. 
B)  The MRSA superbug is a likely suspect. 
C)  The patient may have died from hypotension. 
D)  The patient may not have run a fever if AIDS was present. 
E)  The lipid A in the endotoxin is responsible for the virulence.

Question 18

There is no host cell receptor for the enteropathogenic E. coli (EPEC) intimin adhesion. Describe how this pathogen successfully colonizes human intestines.

Accepted Answer

The pathogen uses the type III

Question 19

State several of the characteristics of pathogenicity islands that suggest they are remnants of transposition.

Accepted Answer

Pathogenicity islands commonly contain a

Question 20

What do the anthrax, E. coli, cholera, and Bordetella toxins have in common?

Accepted Answer

A)  inhibit of protein synthesis 
B)  possess ADP ribisytransferase activity 
C)  cause diarrhea 
D)  disrupt cell membrane 
E)  trigger apoptosis 
A)  inhibit of protein synthesis 
B)  possess ADP ribisytransferase activity 
C)  cause diarrhea 
D)  disrupt cell membrane 
E)  trigger apoptosis

Exam 25: Microbial Pathogenesis

Briefly describe three classic modes of action of bacterial toxins.

A chef cut his finger accidentally while making salad. The next morning he felt pain and warmth and had a little swelling and redness on that finger (signs of inflammation). By night, he was just fine. Which of the following pertains to the chef?

Describe the deregulation of adenylate cyclase activity by cholera toxin.

What characteristics of a pathogen distinguish it from a commensal, in terms of its ability to infect and replicate within a eukaryotic host?

Which of the following does NOT result from the release of endotoxin from Gram-negative bacteria?

Which of the following diseases is transmitted by the mosquito, Aedes aegypti?

Antigenic shifts and phase variants are important virulence assets for which bacteria?

Synthesis of flagella and pili filaments in Gram negatives share which of the following in common?

Commensals do not need virulence factors to survive on their host because:

Protein A helps Staphylococcus aureus avoid :

Superantigens:

Type III and type I pili:

Tropheryma whipplei is the causative agent for Whipple's disease. It could not be cultured until recently when the genomic data showed:

Which of the following produces a toxin that disrupts protein synthesis?

Describe why a blood agar plate can be used to detect the a-hemolytic activity of Staphylococcus aureus.

The toxin gene in Corynebacterium diphtheriae is located on __________.

Which of the following statements is NOT correct about a patient who died from endotoxin pathologies?

There is no host cell receptor for the enteropathogenic E. coli (EPEC) intimin adhesion. Describe how this pathogen successfully colonizes human intestines.

State several of the characteristics of pathogenicity islands that suggest they are remnants of transposition.

What do the anthrax, E. coli, cholera, and Bordetella toxins have in common?

Microbial Life: Origin and Discovery

Observing the Microbial Cell

Cell Structure and Function

Bacterial Culture, Growth, and Development

Environmental Influences and Control of Microbial Growth

Virus Structure and Function

Genomes and Chromosomes

Transcription, Translation, and Bioinformatics

Gene Transfer, Mutations, and Genome Evolution

Molecular Regulation

Viral Molecular Biology

Molecular Techniques and Biotechnology

Energetics and Catabolism

Respiration, Lithotrophy, and Photolysis

Biosynthesis

Food and Industrial Microbiology

Origins and Evolution

Bacterial Diversity

Archaeal Diversity

Eukaryotic Diversity

Microbial Ecology

Microbes and the Global Environment

Human Microbiota and Nonspecific Host Defenses

The Adaptive Immune Response

Microbial Diseases

Antimicrobial Chemotherapy

Clinical Microbiology and Epidemiology

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