Glucose
Glucose (C6H12O6) is a simple carbohydrate, or sugar. It is one of several kinds of sugars. It is important because cells in an organism use it as a source of energy. Turning glucose into energy is called cellular respiration, which is done inside the cells of a living organism. Excess glucose is converted to fats and are stored in adipose tissues.
Glucose is made by plants in a process called photosynthesis. It can also be made by animals in their liver or kidneys.
Having the right amount of glucose available in a person's body is important. Glucose is essential in the proper functioning of the brain. It can be measured with a simple blood test. People that do not have enough glucose have low blood sugar levels. This is a health condition called hypoglycemia. People with too much glucose have hyperglycemia. They might have a health condition called diabetes.
Its chemical formula is C6H12O6. This means it has six carbon atoms, 12 hydrogen atoms, and six oxygen atoms bonded together.
How sugars work, and how glucose can be formed, was studied by a German chemist named Emil Fischer in the 1890s. His work earned him the 1902 Nobel Prize in Chemistry.[1]
Isomers
There are two forms of glucose, the α- and β- forms. The only difference between them is the position of the hydroxyl group, above and below the plane of the ring of the molecule.
For α-glucose, the hydroxyl (-OH) group is below the ring, while for β-glucose, the (-OH) group is above.[2]
Glucose Media
Mutarotation_D-Glucose
Structure of D-glucose
Structure of alpha-D-glucofuranose (Haworth projection)
Structure of beta-D-glucofuranose (Haworth projection)
Structure of alpha-D-glucopyranose (Haworth projection).
Structure of beta-D-glucopyranose (Haworth projection);pl: Struktura beta-D-glukozy (projekcja Hawortha)
different illustrations of alpha-D-Glucopyranose: Tollens (1); Haworth (2); chair (3); absolut stereo (4)
Glucose can exist in both a straight-chain and ring form.
Widely proposed arrow-pushing mechanism for acid-catalyzed dynamic equilibrium between the α- and β- anomers of D-glucopyranose
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Mutarotation: d-glucose molecules exist as cyclic hemiacetals that are epimeric (= diastereomeric) to each other. The epimeric ratio α:β is 36:64. In the α-D-glucopyranose (left), the blue-labelled hydroxy group is in the axial position at the anomeric centre, whereas in the β-D-glucopyranose (right) the blue-labelled hydroxy group is in equatorial position at the anomeric centre.
References
- ↑ "The Nobel Prize in Chemistry 1902 - Emil Fischer". Nobel Prize Committee.
- ↑ "A Guide to α and β Carbohydrates" (PDF). University of California, Los Angeles. Archived from the original (PDF) on 24 January 2014. Retrieved 10 June 2014.
