Biopharmaceutical Chemistry is the study of biomolecules (such as DNA, proteins and carbohydrates) and their applications as therapeutic medicine. Numerous diseases and medical conditions are caused by the improper function or the absence of a particular biomolecule. For example, some forms of diabetes result from a lack of insulin. The role of the biopharmaceutical chemist is to design and synthesise molecules that can substitute for the missing protein. The replacement molecule is often a modified protein, prepared using chemical and biotechnological methods.