Glucose is a carbohydrate, and more specifically, is a monosaccharide, or sugar. It's among the most ubiquitous organic molecules, and is an important component of diet. Table sugar is made up of the sugar sucrose, which consists of one unit of glucose and one unit of a closely related sugar. Starches, like bread and potatoes, are made entirely of chemically-linked glucose molecules. Ingested glucose is absorbed into the bloodstream, and becomes a source of energy for cells. It, like all chemicals, is made up of various elements.
Carbon
Like all organic chemicals, glucose has a carbon backbone. The element carbon is one of the most important to life on Earth as it exists. This is because carbon can form very strong chemical bonds in a wide variety of shapes and patterns, making it not only a stabilizing element within a molecule, but also an element that adds tremendous variety of shape. There are six atoms, or particles, of carbon in glucose, note Drs. Mary Campbell and Shawn Farrell in their book, "Biochemistry." Five of the carbons are arranged into a ring--the ring also contains an atom of another element--and one is found outside the ring.
Oxygen
In addition to carbon, glucose also contains six oxygen atoms. Elemental oxygen is heavier than carbon, and while it can form strong bonds to other elements, it also adds significant chemical reactivity to many of the molecules in which it is found, because bonds from oxygen to other elements break more easily than many other types of bonds. One of the oxygen atoms in glucose is a part of the ring formed by carbon atoms, making a six-membered ring. Six-membered rings in which five of the atoms are carbon and one is an oxygen are called pyranose rings, explain Drs. Campbell and Farrell, and may be chemically reactive. The remaining oxygen atoms in glucose are arranged outside the pyranose ring.
Hydrogen
Glucose contains 12 hydrogen atoms, in addition to its carbon and oxygen. Hydrogen is the lightest element, and in nature, it's found as a gas. Combined with oxygen and carbon, however, hydrogen lends glucose some unique chemical properties. The hydrogen atoms on glucose fall into two categories. Some are attached to carbon, and are relatively unreactive. Others, note Drs. Reginald Garrett and Charles Grisham in their text, "Biochemistry," are attached to oxygen atoms, forming alcohol groups. The many alcohol groups in glucose--five of them, to be precise--make the compound very water soluble. This is important to glucose's ability to dissolve in blood and in the environment inside cells.
References
- "Biochemistry"; Mary Campbell, Ph.D. and Shawn Farrell, Ph.D.; 2005
- "Biochemistry"; Reginald Garrett, Ph.D. and Charles Grisham, Ph.D.; 2007
