First, a hamburger is chewed in the oral cavity, where the carbohydrates are hydrolysed by alfa-amilasa. In the stomach proteins are decomposed by pepsin in the acid medium. Futher, nucleic acids, some carbohydrates and especially lipids are digested by enteropeptidases, nuceases, lipases and other enzymes, which are produced in the pancreas and the small intestine. After that, on the microvilluses of the small intestine generated monomers (aminoacids, glucose etc.) are transported actively or passively through the intestine cells' memranes for the following methabolic pathways (glycolysis, Krebs cycle, lipogenesis etc.). There is a lipids emulsification in the duodenum by bile. From the intestine cells biomonomers are transported to the bloodstream besides the lipids, which are transformed into the chylomicrons and go to other organs with a lymph flowing. Water and some microelements are absorbed in the large intestine, whereas dejection is also formed.