glycolysis
When was the last time you enjoyed yogurt on your breakfast cereal, or had a tetanus shot? These experiences may appear unconnected, but both relate to bacteria which do not use oxygen to make ATP. In fact, tetanus bacteria cannot survive if oxygen is present. However, Lactobacillus acidophilus bacteria which make yogurt and Clostridium tetani bacteria which cause tetanus or lockjaw share with nearly all organisms the first stage of cellular respiration, glycolysis Figure below . Because glycolysis is universal, whereas aerobic oxygen-requiring cellular respiration is not, most biologists consider it to be the most fundamental and primitive pathway for making ATP.