EVERYDAY SCIENCE

Detailed explanation-1: -Obligate anaerobes, which live only in the absence of oxygen, do not possess the defenses that make aerobic life possible and therefore cannot survive in air. The excited singlet oxygen molecule is very reactive. Therefore, superoxide must be removed for the cells to survive in the presence of oxygen.

Detailed explanation-2: -Obligate anaerobes cannot tolerate oxygen because they utilize metabolic schemes built around enzymes that react with oxidants. The reliance upon low-potential flavoproteins for anaerobic respiration probably causes substantial superoxide and hydrogen peroxide to be produced when anaerobes are exposed to air.

Detailed explanation-3: -Examples of obligately anaerobic bacterial genera include Actinomyces, Bacteroides, Clostridium, Fusobacterium, Peptostreptococcus, Porphyromonas, Prevotella, Propionibacterium, and Veillonella.

Detailed explanation-4: -Obligate anaerobes are typically bacteria, and live in a variety of places naturally. Many obligate anaerobes live in the human body, in places like the mouth and gastrointestinal tract where oxygen levels are very low.