A review of why digestion is needed was used to start the class. The chemical composition of carbohydrates was presented along with the nutrients which are carbohydrates. The structure and definition of a polysaccharide as well as a monosaccharide was sketched. The need to convert polysaccharides into monosaccharides in order for absorption into the blood stream and absorption into the cells was discussed. The hydrolysis of starch was outlined, showing the conversion into di and tri saccharides. The chemcical composition of saliva was presented, and that of the enzyme amylase. The action of amylase as a catalyst was explained, as speeding up the chemical reaction of polysaccharide into monosaccharide. The pH of the mouth was looked up, stressing that the enzyme worked best in neutral or slightly basic media.