Integrative Topics II---Digestion and Cellular Metabolism After meals, our body digest the food to break down polymer to monomer. What kind of covalent bonds the digestive system has to break? What is the monomer for carbohydrate, fat and proteins? Where are they absorbed after digestion? Is digestion intracellular or extracellular? Once inside the cells, cells will extract energy from these monomer via metabolism. How do cells break down glucose to retrieve energy (ATP)? What about amino acid and fatty acid-----Where do they join this metabolism? Where glycolysis, Krebs cycle and e transport chain occur? What are the beginning and end products of each reaction? How is energy carried besides ATP?