As their name implies, they are a hydrated form of carbon. The production of carbohydrates during photosynthesis and oxidation of carbohydrates to produce energy constitute the major energy cycle in the biosphere. We will further explore these metabolic pathways involving glucose later in this last third of the course.
Carbohydrates are compounds such as glucose, ribose, deoxyribose, starch and cellulose.
Above is shown the chemical structure of glucose, which is a monosaccharide. The chemical structures of some representative sugars. The sugar from sugar cane is sucrose, a disaccharide made of glucose and fructose. Fructose is what makes table sugar sweet. An oligosaccharide consists of from 2 to several monosaccharides.