Guida verificata passo dopo passo
05:09
03:05
03:40Which of the following does not represent the same mechanism for avoiding host defenses as the others?
a. Rabies virus attaches to the receptor for the neurotransmitter acetylcholine.
b. Salmonella attaches to the receptor for epidermal growth factor.
c. Lymphocryptovirus (mononucleosis) virus binds to the host receptor for complement protein.
d. Surface protein genes in N. gonorrhoeae mutate frequently.
e. none of the above
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.
A drug that binds to mannose on human cells would prevent
a. the entrance of Vibrio enterotoxin.
b. the attachment of pathogenic E. coli.
c. the action of botulinum toxin.
d. streptococcal pneumonia.
e. the action of diphtheria toxin.
Describe the factors contributing to the pathogenicity of fungi, protozoa, and helminths.
The earliest smallpox vaccines were infected tissue rubbed into the skin of a healthy
person. The recipient of such a vaccine usually developed a mild case of smallpox, recovered, and was immune thereafter. What is the most likely reason this vaccine did not kill more people?
a. Skin is the wrong portal of entry for smallpox.
b. The vaccine consisted of a mild form of the virus.
c. Smallpox is normally transmitted by skin-to-skin contact.
d. Smallpox is a virus.
e. The virus mutated.
How can viruses and protozoa avoid being killed by the host’s immune response?
