Microorganisms and Disease
Cholera toxin is an A-B type toxin in which the B portions bind to a receptor on a host cell and the A portion enters the cell to cause

ADP ribosylation of guanylate cyclase that stimulates production of cGMP
cleavage of rRNA that results in disruption of ribosome function
ADP ribosylation of a G protein that locks it into an active form that stimulates adenylate cyclase to make cAMP
ADP ribosylation of adenylate cyclase that stops production of cAMP

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Microorganisms and Disease
The influenza vaccine is administered each year because

it is a polysaccharide vaccine that does not confer long-term protection
the vaccine is sufficiently toxic to make it necessary to administer only a small amount at any one time
None of these
mutations in the viral hemagglutinin may allow the virus to evade the immune response elicited by previous vaccines

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Microorganisms and Disease
Which of the following is common in the disease caused by Coryne-bacterium diphtheriae and Bacillus anthracis?

Diphtheria toxin and edema toxin are ADP ribosylating toxins
Both organisms are gram-positive spore formers
Both organisms cause skin and respiratory tract infections
The most serious disease symptoms are the direct result of toxin action

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Microorganisms and Disease
A major difference between EHEC and EPEC is

EHEC secretes a Shiga-like toxin and EPEC does not
EHEC possesses a type III secretion system and EPEC does not
EPEC passes through the placenta to infect the fetus and EHEC does not
EPEC rearranges host cell actin and EHEC does not

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