how much glucose does the brain use per hour ? why do we get a glycosidic bond whenever a sugar molecule is added to another substance?

4 grams of glucose needed by brain per hour.

    When two glucose molecules come together, the two hydroxyl groups line up along side each other: one combines with a hydrogen atom from the other to form water, in turn forming an oxygen bridge across the two molecules, bonding them and creating a disaccharide- this bond is called a glycosidic bond.