What is the chemical relationship between galactose and glucose?

Galactose and glucose are considered isomers of each other because they share the same molecular formula, C6H12O6, but differ in the arrangement of their atoms. This means that while they have the same number of carbon, hydrogen, and oxygen atoms, the specific structure of these molecules is different, leading to varying properties and functions in biological systems.

For instance, glucose is a primary energy source for cells, while galactose is typically found in dairy products and must be converted into glucose by the liver before it can be utilized for energy. This structural variation is what characterizes them as isomers, which are compounds that have the same chemical formula but different structural formulas and, as a result, different chemical properties.

The concept of being identical sugars is incorrect because, as mentioned, their structural differences lead to different functions. While they can indeed form disaccharides when coupled with each other or other sugars, this does not define the direct relationship between the two. Similarly, the classification of both as plant sugars is misleading since galactose is not predominantly found in plants; it's mostly associated with lactose in milk. Therefore, the relationship between galactose and glucose is best described by the fact that they are isomers of