Glycolysis of glucose: in this process, six carbon glucose is broken down into two molecules of three carbon pyruvate. Since bonds are broken in this process, energy is released and then captured in two molecules of atp. This process occurs in the cytoplasm of the cells and does not require oxygen, making it an anaerobic reaction (does not require oxygen). Breakdown of pyruvate: this step occurs in the inner part of the mitochondria. Pyruvate catabolism depends on if there is oxygen or not. In aerobic conditions, there is enough oxygen present and acetyl coa is formed with the presence of coenzyme a. This aerobic process also leads to the loss of some electrons, which are captured by the electron transporter nadh+h+, and some carbon dioxide is also released in this process. In anaerobic conditions, there is not enough oxygen present and pyruvate is oxidized into lactate.