Question

An organism that grows on the plate in the anaerobic jar and the plate incubated in the presence of atmospheric oxygen (O₂) would be classified into which of the following categories? (Check all that apply.)

Group of answer choices

a) Strict aerobe

b) Facultative anaerobe

c) Aerotolerant anaerobe

d) Strict anaerobe

e) Microaerophile

Answer 1

A strict aerobe (obligate aerobe ) cannot grow in the absence of oxygen whereas a strict (obligate ) anaerobe can not survive under atmospheric oxygen levels as oxygen would be toxic for such organisms. Microaerophiles need oxygen at very low levels to survive but higher levels of oxygen are toxic for them as well. Facultative anaerobes switch to anaerobic fermentation in the absence of oxygen but prefer atmospheric conditions since aerobic metabolism provides more energy in terms of ATP yield. An aerotolerant anaerobes metabolism is always anaerobic, however, it is not affected by the presence of oxygen.

So, Facultative anaerobes and aerotolerant anaerobes would be able to thrive both in the presence and absence of oxygen at atmospheric levels.