Translations:Adventist Youth Honors Answer Book/Nature/Bacteria/62/en

Bacteria, whether autotrophs or heterotrophs, may be either Aerobic (requiring oxygen as part of their respiration) or anaerobic (either not requiring oxygen, or being unable to grow in the presence of atmospheric oxygen). Bacteria that require oxygen for their metabolic functions are called obligate aerobes, while those that cannot live in the presence of oxygen are called obligate anaerobes. Between them there are different gradations of oxygen tolerance. Microaerophyllic bacteria live best in low-oxygen environments. Facultative anaerobes are capable of living without oxygen, but thrive in the presence of oxygen. And aerotolerant anaerobes are those that live best without oxygen, but are generally unaffected negatively by the presence of oxygen.