Answer:
They have a double-bonded oxygen in different locations.
Step-by-step explanation:
Glucose and fructose are simplest sugar. They cannot be simplified further so, they are both monosaccharides. They have the same chemical composition but a different molecular, structure. Glucose is an aldo-sugar, its carbon attached to hydrogen through a single bond and oxygen by a double bond. Whereas fructose is a keto-sugar in which only oxygen atom attached to carbon by a single bond