D-Glucose, short for dextrorotatory glucose is a simple sugar which is very critical for energy in many organisms, including humans. D-Glucose is a monosaccharide, which is a sugar which can not be broken down into simpler molecules. They make up the building blocks of disaccharides and polysaccharides, which are multiple sugars bonded togehter for advanced purposes. D-Glucose is in many polysaccharides such as gylcogen, starch, and cellulose. Monosaccharides, like D-glucose contain at least three carbon atoms by definition, one of which is attached to oxygen, while the other two are attached to hydrogen. However, the specific chemical formula of D-glucose is C6H12O6 which in an empirical formula has the ratio of atoms of 1:2:1. It occurs naturally in many fruits, as well as being produced in the liver and kidneys. It is the primary source of energy for organisms.