Monosahhariide

Monosahhariide, more commonly written as monosaccharide, refers to the simplest class of carbohydrates. Monosaccharides cannot be hydrolyzed into simpler sugars and serve as the fundamental building blocks for disaccharides and polysaccharides. They are composed of carbon, hydrogen, and oxygen with a general formula of (CH2O)n, where n typically ranges from three to seven. Based on the functional group, monosaccharides are classified as aldoses, which contain an aldehyde group, and ketoses, with a ketone group. They are usually colorless, crystalline solids in pure form and can be soluble in water.

In solution, many monosaccharides exist in cyclic forms arising from intramolecular condensation between the carbonyl group and a hydroxyl group. The ring contains an anomeric carbon that can assume alpha or beta configurations. They are optically active and predominantly occur in the D-configuration in nature. Common examples include glucose (a hexose aldose), galactose (a hexose aldose), and fructose (a hexose ketose).

Role and metabolism: Monosaccharides provide immediate energy for cells through glycolysis, contribute to nucleotide synthesis (ribose and deoxyribose), and serve as intermediates in metabolic pathways. They can be absorbed from the diet as monosaccharides or produced by digestion of more complex carbohydrates. Their versatility underpins many biological processes and industrial applications, including nutrition, fermentation, and the synthesis of polysaccharides and glycoproteins.