Physical Properties of Glucose

Glucose is a tiny molecule of sugar. Glucose circulates in the blood and is used as energy for cellular reactions. Glucose is found in the diet in the form of carbohydrates. The larger carbohydrate molecule is broken down in the stomach and the small intestine using enzymes. The enzymes break down the larger molecule into the small glucose parts that can be absorbed by cells using insulin interaction.

Stereoisomers

Glucose is one molecule, but there are two versions of the chemistry. In chemistry, the "D" and "L" forms are prominent in nature. However, in carbohydrates such as glucose and fructose, the most important forms are the "D" forms. The difference between the two stereoisomers is the way the 5th carbon bonds are situated. For D-glucose, the representation of the molecule is shown with the OH group on the right side.

Structure

The glucose molecule follows the same rules as other carbohydrates. The C6H12O6 formula defines glucose. This formula indicates that there are six carbon atoms, twelve hydrogen atoms and six oxygen atoms. The way the carbons are situated in a Fischer projection model indicates the name of the carbohydrate molecule. The Fischer projection model is in the image above.

Bonds

The bonds of the glucose model are single bonds within the central carbons. There is also a single bond in the trailing OH group on the 6th carbon. However, there is one double bond on the first carbon. The carbon double bonds to an OH group as well. The difference in bonds is how a student knows how to properly write a Fischer projection for a carbohydrate molecule.

Metabolism

The glucose molecule is one of the main biomolecules used in metabolism. Metabolism is categorized by catabolism (breakdown of molecules) and anabolism (creation of biomolecules). Glucose is catabolized into smaller units to create energy. The glucose molecule is broken down to 2 pyruvates, which are used in the synthesis of ATP. ATP is the energy currency of the cell, and it is responsible for energy coupling for internal chemical reactions.

Insulin

Insulin is a hormone that is created by the pancreas. Insulin allows the uptake of glucose into the cell for metabolism. Diabetes is a disease in which insulin levels are affected, and the body is not able to properly uptake glucose into cells. Glucose molecules circulating in the body work with insulin to provide natural levels in the blood.

Diabetes has two types. Type I diabetics have an autoimmune disorder. White blood cells that are supposed to protect the body against infection attack the pancreas cells that create insulin. Since insulin is necessary for glucose intake into the cell, destruction of these cells leaves the body with unusable glucose and an inability to use the molecule for energy. Type II diabetes is usually associated with obesity. The cells in the body become resistant to the effects of insulin, so glucose builds up in the blood. Both these types of diabetes reduce the body's ability to use glucose, which is a primary molecule for energy.

References

• Bio-medicine.org
• MayoClinic