Stomach the small intestine, where the extraction of nutrients begins. Depending on the quantity and contents of the meal, the stomach will digest the food into chyme within anywhere between forty minutes and a few hours. The average human stomach can comfortably hold about a litre of food. Gastric juice in the stomach also contains pepsinogen. Hydrochloric acid activates this inactive form of enzyme into the active form, pepsin. Pepsin breaks down proteins into polypeptides. Although the absorption in the human digestive system is mainly a function of the small intestine, some absorption of certain small molecules nevertheless does occur in
Xeno nucleic acid theory of XNA utilization is its incorporation into medicine as a disease-fighting agent. Some enzymes and antibodies that are currently administered for various disease treatments are broken down too quickly in the stomach or bloodstream. Because XNA is foreign and because it is believed that humans have not yet evolved the enzymes to break them down, XNAs may be able to serve as a more durable counterpart to the DNA and RNA-based treatment methodologies that are currently in use. Experiments with XNA have already allowed for the replacement and enlargement of this genetic alphabet, and XNAs have shown complementarity with