**3. Changes in metabolism (Figure 2)**

In the presence of oxygen, human cells respire and derive their energy from the complete degradation of food (fats, carbohydrates and amino acids) by specific oxidative processes that fuel oxidative phosphorylation. A lack of oxygen completely changes these metabolic pathways, disrupting glycolysis and inhibiting the degradation pathways of lipids (beta-oxi‐ dation), amino acids and oxidative phosphorylation.
