In which form does glucose predominantly exist?

Glucose predominantly exists as a hexose because it is a six-carbon sugar (C6H12O6). The classification of carbohydrates is often based on the number of carbon atoms they contain. In this classification system, a triose has three carbons, a pentose has five, and a hexose has six. Since glucose has six carbons, it falls into the hexose category. Hexoses, including glucose, play critical roles in metabolism and are vital sources of energy for living organisms due to their ability to undergo glycolysis and other metabolic pathways. Understanding the structure and classification of sugars is essential for grasping how they function in biological systems, which is a fundamental concept in biochemistry and biology relevant to the MCAT.