| Monosaccharides | Simplest carbohydrates with one sugar unit | Glucose, Fructose, Galactose |
| Disaccharides | Composed of two monosaccharide units linked together | Sucrose (Glucose + Fructose), Lactose (Glucose + Galactose), Maltose (Glucose + Glucose) |
| Oligosaccharides | Contain a small number (3 to 10) of monosaccharide units linked together | Components of glycoproteins and glycolipids |
| Polysaccharides | Large, complex carbohydrates composed of numerous monosaccharide units | Starch (in plants), Glycogen (in animals), Cellulose (in plant cell walls), Chitin (in exoskeletons and fungal cell walls) |
| Hexoses | Monosaccharides with six carbon atoms | Glucose, Fructose, Galactose |
| Pentoses | Monosaccharides with five carbon atoms | Ribose, Deoxyribose (found in nucleic acids) |
| Trioses | Monosaccharides with three carbon atoms | Glyceraldehyde |