The Brain (right) uses glucose as an energy source. (wikimedia.org)
Glucose is an important because it is a large component of sugar. During the age of Exploration, sugar was one of the many things that caused and supported the slave trade. The harvesting, and processing of sugar from the sugar cane was a labor intensive process that required many slaves to work in the plantations of the Caribbean and Latin America.
Glucose is the most common of the monosaccharides, or simple sugars. The structure of Glucose is a straight chain in which Oxygen, Hydrogen, and hydroxide molecules are bonded to carbon molecules. The Human Body, in particular, the Brain, uses glucose for energy. Neurons are dependent on a second to second supply of glucose from the bloodstream for their energy as they do not have any energy reserves. If blood glucose levels fall below 50% of the normal level, symptoms of brain dysfunction occur, and if it falls below 25% of the normal level then a coma may result. Furthermore, your glucose levels have an affect on when you are hungry and when your not. When glucose levels within the body fall, then you feel hungry. Likewise, if the glucose levels are high, then you feel full.