Monosaccharides can be divided into two groups based on the aldehyde or ketone group.
1. Aldose: Monosaccharides containing aldehyde groups are called aldoses. Such as glucose, erythrose, ribose, mannose etc. Dr. Siddiq Publications
2. Ketose: Monosaccharides containing ketone group are called ketose. Such as fructose, erythrulose, ribulose, dihydroxyacetone etc.