In hydrolysis, a large molecule is broken down into smaller components, with the addition of a molecule of water. The digestion of foods is an example of hydrolysis. An example is a disaccharide like sucrose, being broken down into glucose and fructose, both monosaccharides. There is a bond called a glycoside bond which is in the center of the two monosaccharide units. By adding water, this bond breaks and the larger sugar becomes two simple sugars, or monosaccharides. Of course, enzymes aid in facilitating this process. Dehydration synthesis is like the opposite of hydrolysis. In this case, by removing a molecule of water, two small molecules can connect to form a larger one. An example is when two amino acids join together to form a dipeptide. A peptide bond forms after a reaction between the carboxyl group of one amino acid and the amino group of the next amino acid. The carbon from one amino acid connects to the nitrogen from the other amino acid and a peptide bond is the result, with the removal of a H atom from one amino acid and an OH from the other. These combine to form water, hence the term--dehydration synthesis. In a synthesis reaction, two smaller molecules combine to form a larger molecule. Dehydration synthesis is responsible for storing excess glucose molecules as a much larger polysaccharide like starch or glycogen.