Glucose is an important fuel released from sugar. Glucose belongs to the carbohydrates. Glucose arises from the digestion of other carbohydrates. The animal needs fuels to function. The fuels are a source of energy. The animal absorbs glucose into the blood and through the blood it then ends up in tissues that can burn glucose. The animal's body ensures that the supply of glucose remains constant. Diabetes occurs when the regulation of glucose balance is disrupted.