Glucose is a carbohydrate. It is a simple sugar that serves as a primary source of energy for living organisms. Carbohydrates are one of the four major classes of biomolecules, which also include proteins, lipids, and nucleic acids.
Glucose is a monosaccharide, meaning it is the simplest form of carbohydrate and cannot be broken down into smaller sugar units. It plays a crucial role in cellular respiration, where it is metabolized to produce ATP, the energy currency of the cell.
In summary, glucose is classified as a carbohydrate, not a protein, lipid, or nucleic acid.