Glucose is a sugar with the molecular formula C6H12O6, and is a component of a variety of carbohydrates in the body.Glucose is called a simple sugar or a monosaccharide because it is one of the smallest units which has the characteristics of this class of carbohydrates. Glucose is made during photosynthesis from water and carbon dioxide, using energy from sunlight. The reverse of the photosynthesis reaction, which releases this energy, is an important source of power for cellular respiration.
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.
The primary function of glucose to provide energy for physiological processes such as respiration, muscle contraction and relaxation, heart rhythm and the regulation of body temperature. Roughly half of the energy required by the body is supplied by glucose and a stored carbohydrate called glycogen, according to Oklahoma State University Cooperative Extension Service.
The brain, neurons and developing red blood cells can only use glucose for energy. If your intake of carbohydrates is inadequate, your body will draw on glycogen stores to give the brain fuel. Once the stores fail, the body begins to break down muscle tissue to make glucose. In other words, carbohydrates are indispensable for a healthy body. You need at least 50 to 100 grams of carbohydrates per day to prevent muscle breakdown, according to according to Oklahoma State University Cooperative Extension Service.