Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

50 Cards in this Set

  • Front
  • Back
What are the three main categories of exotoxin?
cytolytic toxins
What are the two types of toxin?
What do cytolytic toxins do? Give an example.
attack cell components causing lysis. Staphylococcus aureus hemolysin lyses red blood cells.
What do neurotoxins do? Give an example.
interfere with nerve cell function. tetanus toxin.
What do enterotoxins do? Give an example.
affect cells lining intestinal tract. eg cholera toxin
Define exotoxin
a secreted protein made by Gram-positive and negative bacteria
Are exotoxins immunogenic?
Are exotoxins heat labile (sensitive)?
What is the most common endotoxin produced by Gram(-) bacteria?
What is the most common endotoxin produced by Gram(+) bacteria?
lipoteichoic acid
Define endotoxin
non-protein toxin molecule
Are endotoxins immunogenic?
not really
___toxins are proteins excreted by bacteria, and are generally heat labile
___toxins are LPS-lipoprotein complexes released on cell lysis as part of the outer membrane of Gram(-) bacteria
___toxins are extremely heat stable
___toxins act specifically
cytotoxins, enterotoxins, and neurotoxins are all ___toxins
___toxins are highly toxic, often fatal, whereas ___toxins are weak and rarely fatal
exo, endo
___toxins are relatively poor immunogens, whereas ___toxins are very good immunogens and stimulate productionf of neutralizing antibodies
endo, exo
toxoids cannot be made from ___toxins
treatment of ___toxins with formaldehyde or heat yields a toxoid
___toxins do not produce fever in host
___toxins often produce fever in host
Vibrio cholerae uses a ___toxin to damage its host
Describe the Vibrio cholerae morphology
Gram(-) curved rod
single, polar flagellum
Where can Vibrio cholerae survive?
fresh or brackish water
small intestine of humans
What is Vibrio cholerae host range?
only humans
Vibrio cholerae strains are serotyped based on thier ___ antigen
LPS O antigen
Two serogroups known as __ and __ are responsible for cholera outbreaks
O1 and O139
Vibrio cholerae has three major virulence factors. What are they?
cholera toxin
Tcp pili
How is cholera spread?
fecal contamination of water and food
Cholera occurs usually in ___
What are the cholera symptoms?
Massive diarrhea (rice water stool containing 10^8 vibrios), resulting in electrolye loss, dehydration, anuria, acidosis, and shock
Describe the structure of cholera toxin
multimeric protein complex composed of five identical binding (B) subunits and an A (enzymatic) subunit
one of the B subunits of CT binds to a ___ receptor, causing the ___ to be cleaved
glycolipid. A subunit
After cleavage, the A1 portion of the A subunit enters into ___
the cytosol of the intestinal epithelial cell
___ activates the host cell's adenylate cyclase enzyme, which does what?
A1. It converts ATP into cAMP.
What does cAMP do?
stimulates the secretion of large amounts of Cl ions from cell into lumen of intestine
The loss of chlorine ions from intestinal epithelial cells results in what?
An electrical gradient that pulls sodium, potassium and other ions from cells, causing new electrolyes to be pulled from blood
What is the overall effect of cholera toxin on cells?
It turns them into pumps for water and electrolytes
How is cholera spread?
fecal-oral route
Is Vibrio cholerae acid sensitive?
Why is a large dose of Vibrio cholerae required to produce disease?
A lot of the Vibrio cholerae die because of gastric acidity
Vibrio cholerae are well adapted to survive in what part of the GI tract?
small intestine
How does Vibrio cholerae withstant propulsive gut activity?
by swimming
Vibrio cholerae lacking TCP pili are still pathogenic (T/F)
What does Vibrio cholerae TCP pili do?
causes bacteria to aggregate
facilitates adherence to the intestinal mucosa
What is the treatment for cholera?
rapid replacement of fluids and electrolytes through Gatorade-like solution
Describe the current cholera vaccine. What serogroups is it effective against?
CVD 103-HgR is an oral, live, attenuated cholera vaccine effective only against O1 serogroup
Recurrent infections of cholera are rare (T/F). Why?
T. Antibodies are developed during first infection.