Lecture 1 review questions Flashcards
In the scientific names below, which designates the STRAIN?
Escherichia coli B12
Bacillus subtilis
E. coli
Escherichia
B. subtilis
B12
Who has a cell wall? Who does not?
Algae
Fungi
Protozoa
Has: algae, fungi
Doesn’t have: protozoa
True or false: Bacteria that look alike are probably members of the same species. Why?
This is false. Recall that there are only a few shapes in the bacterial world: spherical (round), cylindrical (rod-shaped), or spiral. Completely unrelated bacteria may have the same shape—for example, two different, unrelated species of Bacillus may look very similar.
Which of the following are limitations of Koch’s postulates?
Check All That Apply
A. The suspected pathogen infects animals but not humans.
B. The suspected pathogen cannot be cultured in the laboratory.
C. There is not a suitable experimental host for the suspected pathogen.
D. The suspected pathogen produces disease both in humans and a suitable test animal.
E. The disease is polymicrobial, caused by more than one pathogen.
A,D,E
This is a limitation of Koch’s postulates. If the suspected pathogen cannot be isolated and grown in the laboratory in pure culture, then there will not be a source of pure pathogen to inoculate a test animal.
This is a limitation of Koch’s postulates are not applicable in all situations. With some diseases, particularly viral diseases, there may not be a suitable test animal that can be inoculated, because many viruses exhibit very narrow host ranges. Also, for ethical reasons, humans are not typically used for this sort of experimentation.