Carbohydrates are made up of monosaccharides linked together into polysaccharide chains by a type of covalent bond known as a glycosidic bond. These glycosidic bonds are formed in a dehydration synthesis reaction.
These glycosidic bonds are formed in a dehydration synthesis reaction. It is when one sugar gives up a hydrogen atom from a hydroxyl group and the other sugar gives up the entire hydroxyl group. As H2O is formed an oxygen atom is left between two covalent bonds linking the two sugars.