Microaerophiles that grow best with a high concentration of carbon dioxide in addition to a low level of oxygen are called:

a. Aerotolerant

b. Capnophiles

c. Facultative anaerobes

d. Fastidious

Label each of these thioglycolate tubes to indicate the oxygen requirements of the microbes growing in them.

Which genus is the most common anaerobic human pathogen?

a. Bacteroides

b. Spirochetes

c. Chlamydia

d. Methanopyrus

Which of the following terms best describes an organism that cannot exist in the presence of oxygen?

a. Obligate aerobe

b. Facultative aerobe

c. Obligate anaerobe

d. Facultative anaerobe

Organisms that require oxygen for metabolism are referred to as…

Organisms that are indifferent to the presence of oxygen are…

The enzyme(s) that deal with toxic oxygen-containing molecules is/are

_____________ microbes use oxygen in metabolism, while _____________ do not.