Texas Southern University - BIOL 347

Chapter 17

Host-Microbe Interactions

Matching Questions

1)Which of the following best matches the description:

1. able to produce disease in a host with impaired defenses                 avirulent  
2. disease-causing organism      colonization    
3. microbe lacks the ability to cause disease                  opportunist  
4. establish microbial growth on a body surface            pathogen    

True / False Questions

2. The most successful parasites are the ones that live in harmony with their hosts.

3. A human fetus has no resident microbial population.

4. Infection always leads to disease.

5. A disease is an infection that impairs the normal state of health.

6. Obligate intracellular parasites may be grown in special synthetic media.

7. During incubation and convalescence a person may still spread infectious organisms.

8. The infectious dose of most pathogens is about equal.

9. A strong attachment of a microorganism to a host cell automatically leads to disease.

10. High concentrations of some bacteria are necessary for successful invasion because only at high density are their virulence genes expressed.

11. Only Gram-positive bacteria produce exotoxins.

Essay Questions

12. What reason could there be for some people to doubt that HIV is the causative agent of AIDS?