<P> Sucrase is an enzyme that breaks down the disaccharide sucrose, commonly known as table sugar, cane sugar, or beet sugar . Sucrose digestion yields the sugars fructose and glucose which are readily absorbed by the small intestine . </P> <P> DNA and RNA are broken down into mononucleotides by the nucleases deoxyribonuclease and ribonuclease (DNase and RNase) from the pancreas . </P> <P> Some nutrients are complex molecules (for example vitamin B) which would be destroyed if they were broken down into their functional groups . To digest vitamin B non-destructively, haptocorrin in saliva strongly binds and protects the B molecules from stomach acid as they enter the stomach and are cleaved from their protein complexes . </P> <P> After the B - haptocorrin complexes pass from the stomach via the pylorus to the duodenum, pancreatic proteases cleave haptocorrin from the B molecules which rebind to intrinsic factor (IF). These B - IF complexes travel to the ileum portion of the small intestine where cubilin receptors enable assimilation and circulation of B - IF complexes in the blood . </P>

Which component of the gi system completes food digestion