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

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

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Microorganisms and Disease
The influenza vaccine is administered each year because

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

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