Final answer:
The described molecule is glucose, a six-carbon monosaccharide with a hydrogen and oxygen bonded to the first and last carbons; it is an aldose sugar, unlike fructose, which is a ketose, or ribose, which has five carbons.
Step-by-step explanation:
The description given in the student's question corresponds to a monosaccharide structure, with carbon atoms bonded to hydrogen and oxygen atoms. In identifying the sugar by the described structure it corresponds to glucose - an aldose sugar with six carbons, where the first and last on the chain are each bonded to a hydrogen atom on top and one side and an oxygen atom on the other. The description mentions oxygen being bonded to the second carbon which suggests a ketose sugar, but combining this with the earlier and later description, we can determine that glucose is the most likely correct answer. Glucose is an important monosaccharide with a six-membered ring structure in its cyclic form, differing from fructose, which forms a five-membered ring, and galactose, which has a different arrangement of hydroxyl groups. Ribose, on the other hand, is not a hexose sugar, as it has only five carbon atoms.