Which of the following is a monosaccharide?

Glucose is classified as a monosaccharide because it is the simplest form of sugar, consisting of a single sugar molecule. Monosaccharides are the building blocks of carbohydrates and cannot be hydrolyzed into simpler sugars. Glucose, specifically, has the chemical formula C6H12O6 and plays a crucial role in providing energy for cells in many organisms.

In contrast, starch, sucrose, and cellulose are all polysaccharides or disaccharides. Starch is a complex carbohydrate made up of many glucose units linked together, serving as a storage form of energy in plants. Sucrose, on the other hand, is a disaccharide consisting of one glucose molecule and one fructose molecule, which means it is made up of two monosaccharides bonded together. Cellulose, like starch, is a polysaccharide composed of long chains of glucose but is a structural component in the cell walls of plants.

Understanding the classification of these carbohydrates helps clarify how they function in biological systems and metabolism, with monosaccharides being essential for immediate energy availability.