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.

Detailed explanation-3: -Obligate aerobes survive and grow with oxygen. Obligate anaerobes cannot survive in an oxygen-containing environment; the presence of oxygen leads to cell death. Facultative anaerobes can toggle between aerobic metabolism can switch to anaerobic metabolism.

Detailed explanation-4: -Obligate anaerobes are found in oxygen-free environments such as the intestinal tracts of animals, the deep ocean, still waters, landfills, in deep sediments of soil.

Detailed explanation-5: -Obligate anaerobes typically live in oxygen-free places, such as in the gut of an animal or in the mud. These sensitive organisms can only tolerate oxygen concentrations of <0.5% to 8%. Obligate anaerobes metabolize energy using a process not coupled with the consumption of oxygen.