Bacterial pathogen Z has proteins on its surface which bind to receptors on the host cell's surface. After it is bound, the host cell engulfs the bacterium. This means that the proteins on the surface of bacterium Z are:

Which of the following statements is false?

a. E. coli never causes disease

b. E. coli provides vitamin K for its host

c. E. coli often exists in a mutualistic relationship with humans

d. A disease-causing strain of E. coli causes bloody diarrhea

The ID₅₀ for Campylobacter sp. is 500 cells; the ID₅₀ for Cryptosporidium sp. is 100 cells. Which of the following statements is false?

a. Both microbes are pathogens.

b. Both microbes produce infections in 50% of the inoculated hosts.

c. Campylobacter is more virulent than Cryptosporidium.

d. Campylobacter and Cryptosporidium are equally virulent; they cause infections in the same number of test animals.

e. Cryptosporidium infections are acquired more easily than Campylobacter infections.

Which of the following statements is true?

a. The primary goal of a pathogen is to kill its host.

b. Evolution selects for the most virulent pathogens.

c. A successful pathogen doesn't kill its host before it is transmitted.

d. A successful pathogen never kills its host.

Which of the following genera is the most infectious?

If C. tetani is relatively sensitive to penicillin, why doesn’t penicillin cure tetanus?

Compare and contrast cat-scratch disease and toxoplasmosis.

Why is C. perfringens likely to grow in gangrenous wounds?