The carbohydrate glucose is very important substance in biology and in metabolism of all life forms. Glucose is a simple sugar, or monosaccharide, and is the main and preferred source of energy for red blood cells, the brain and the nervous system. Glucose also plays a role in the creation or synthesis of other substances like glycoproteins or glycolipids. It can create or synthesize polysaccharides, which are complex sugars that can be used as energy storage in organisms as well.
In most organisms, glucose is the main energy source, according to the book, "Nutrition and Diet Therapy." Most of the cells in the body utilize glucose, but can convert other substances to energy when the levels of glucose are too low; other cells, like those in the brain, rely solely on glucose for energy. Glucose can be broken down by a process called glycolysis into pyruvate and packets of energy called ATP, according to the University of Illinois in Chicago. Glycolysis alone does not form that much ATP; however, in some organisms, the pyruvate is further broken down into carbon dioxide and water through the citric acid cycle. The citric acid cycle creates more energy for cells to use than glycolysis.
Glucose is a component of a variety of carbohydrates in the body. It can form disaccharides like sucrose, which is also known as table sugar, or lactose, which is the sugar found in milk, according to the book "Nutrition." Glucose can also form polysaccharides, such as glycogen, which is a form of energy storage. When the amount of glucose exceeds the amount of energy needed by the body, the extra glucose is converted into glycogen and stored in the liver. When the body's energy needs increasing, the glycogen is changed back into glucose.
Glucose can also play a role in the creation of non-carbohydrate molecules as well. Glucose is part of the pathway that creates the building blocks for either DNA or RNA, according to Chronolab.com. According to EdInformatics.com, glucose is vital to the production of proteins and lipids, and may help the protein or lipid assume its appropriate folded shape. Glucose also plays a role in the production of vitamin C.
- University of Illinois in Chicago:BIOS 100 Lecture Material Online - Glycolysis, Krebs Cycle, and other Energy-Releasing Pathways
- "Nutrition and Diet Therapy;" Linda K. DeBruyne, Kathryn Pinna and Eleanor Noss Whitney; 2007.
- EdInformatics.com: Glucose
- "Nutrition;" Paul Insel, Don Ross, Kimberley McMahon, Melissa Bernstein; 2011.
- Chronolab,com: Glucose
- Stockbyte/Stockbyte/Getty Images
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