Glucose gets its name from the Greek word glykys, which means sweet. Its chemical formula is C₆H₁₂O₆. It is commonly known as dextrose and belongs to the group of carbohydrates known as simple sugars (monosaccharides). Found in fruits and honey, it is the most common free sugar in higher animals’ blood. It powers cell function, and its metabolism must be carefully regulated. The principal energy-reserve carbohydrate in plants, starch, is made of thousands of linear glucose units. Another important glucose-based molecule is cellulose. Dextrose is the D-glucose molecule.

Composition of Glucose

Glucose is made of six carbon atoms, 12 hydrogen atoms, and six oxygen atoms. The -OH on carbon number 5 converts to the ether linkage to seal the ring with carbon number 1 due to the tetrahedral geometry of carbons that eventually form a 6-membered stable ring. This results in a ring with six members, i.e., five carbons and one oxygen.

Structure of Glucose

• Open-chain form: Glucose has a backbone that is not open or branched, and it is made of six carbon atoms in its open-chain form.

• Molecular formula: The molecular formula of glucose is C₆H₁₂O₆ based on the analysis of elements in glucose and the molecular weight of glucose.
• Presence of a 6-carbon unbranched chain: Glucose has an unbranched six-carbon chain, proven by the fact that it totally reduces when combined with concentrated hydrogen iodide and red phosphorus to produce n-hexane.
• Presence of 5 OH groups: Pentadactyl derivatives are formed when glucose reacts with acetic anhydride, indicating five hydroxyl groups. As glucose is a stable molecule, it is impossible for any two OH groups to bind to the same carbon. Thus five OH groups are present on various carbons. An oxime is formed when glucose interacts with hydroxylamine, proving the presence of a carbonyl group.
• Presence of terminal CHO function: Upon being mildly oxidised with bromine water, the glucose molecule transforms to glucose acid, which is then reduced with a large amount of HI to produce hexanoic acid.
• Because glucose contains a straight 6-carbon chain with a terminal CHO, the five OH groups can be placed on each of the remaining five carbons to form an open-chain glucose structure. This meets the four valencies of the carbon atom by delivering hydrogen atoms to these carbon atoms.

Conclusion

Glucose is a carbohydrate and a vital biomolecule that aids in the body’s metabolism. It has the chemical formula C₆H₁₂O₆ and is a simple sugar. Comprising six carbon atoms, 12 hydrogen atoms, and six oxygen atoms, glucose is often known as dextrose or blood sugar and is a readily available monosaccharide. It is chiefly produced by plants and most algae during photosynthesis. The aldehyde group combines with a hydroxyl group to form a hemiacetal ring structure in glucose. Many of glucose’s reactions are explained by its ring structure. Normally, the concentration of glucose in the blood is maintained between 80 and 120 mg/dl.