Obligate anaerobes carry out fermentation or anaerobic respiration and cannot survive in the presence of O2.
Yeast and many bacteria are facultative anaerobes, meaning that they can survive using either fermentation or cellular respiration.
In a facultative anaerobe, pyruvate is a fork in the metabolic road that leads to two alternative catabolic routes.
Fermentation and aerobic respiration are anaerobic and aerobic alternatives, respectively, for producing ATP from sugars.
ATP generated by cellular respiration is due to oxidative phosphorylation.
Without electronegative oxygen to pull electrons down the transport chain, oxidative phosphorylation stops.
Respiration and Photosynthesis Essay ..