5. The figure depicts the structural formulas of glucose, galactose, and fructose. (a) Circle the functional groups that classify the sugars either an aldose or a ketose, and identify each sugar as one or the other. (b) The chemical formula of these compounds is the same, although the structural formula is different. What are such compounds called?

a) The functional groups that classify the sugars as either an aldose or a ketose are:

- Glucose: Aldose
- Galactose: Aldose
- Fructose: Ketose

b) Compounds with the same chemical formula but different structural formula are called isomers.