Ketoses

The C O group can also exist as a ketone, where the C atom of the C O is joined to two other carbon atoms. These are present in certain sugars with the general name of ‘ketoses’, of which fructose is an example. Note that aldoses and ketoses can be isomers to each other. Fructose can also exist as a ring structure (Figure 4.4). There is a frightening number of combinations of isomers and structural arrangements for these simple sugars but our bodies are very selective in the ones they require for cell building. You can see that, even when considering these simple molecules, the variations of their structures make them very versatile and important for systems
within cells.