There are a few common ways in which glucose could be oxidized. The first is oxidation to an aldonic acid in which the aldehyde group of glucose is oxidized to a carboxylic acid. This occurs in basic solution in the presence of an oxidizing agent and is commonly used as a test of whether a sugar is an aldose or a ketose.
Carbon 6 of glucose can be oxidized from an alcohol to a carboxylic acid via an enzyme catalyzed reaction. This reaction produces D-glucuronic acid, an important component of the polysacchardies in the extracellular matrix.
Periodic acid can also oxidize many carbohydrates including glucose. Periodic acid induces a breakage in carbon-carbon bonds where the adjacent carbons both have hydroxyl groups. In the reaction, the hydroxyls are oxidized to carbonyl groups.
[edit: thanks for noticing the typo, Borek]