Glucose is a simple sugar with the molecular formula C6H12O6. Common names for glucose include blood sugars, dextrose, corn sugar, d-Glucose, grape sugar.

Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using energy from sunlight, where it is used to make cellulose in cell walls, the most abundant carbohydrate in the world.

In energy metabolism, glucose is the most important source of energy in all organisms. Glucose for metabolism is stored as a polymer, in plants mainly as starch and amylopectin, and in animals as glycogen. Glucose circulates in the blood of animals as blood sugar.

The name glucose is derived from Ancient Greek γλεῦκος (gleûkos, "wine, must"), from γλυκύς (glykýs, "sweet"). The suffix "-ose" is a chemical classifier, denoting a sugar.

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