| Term | Definition |
| Carbohydrate | macromolecule which is the main energy source of living things |
| monosaccharide | the monomer of carbohydrates or simple sugars |
| isomers | compounds with the same chemical composition but with a different shape |
| glucose | monosaccharide which is the main enegy source of the cell |
| fructose | monosaccharide which is found in honey and fruits, the sweetest monosaccharide |
| galactose | monosaccharide found in the milk of mothers |
| disaccharide | molecule made up of two monosaccharides |
| polysaccharide | a complex molecule made up of three or more monosaccharide |
| glycogen | the molecule found in the liver of animals which is a polymer made up of glucose |
| starch | in plants glucose molecules are linked to form this polymer |
| cellulose | is a polysaccharidewhich is found in plants and cannot be digested |