monozaharid

Monosaccharide, also known as monozaharid in some languages, is the simplest class of carbohydrates. These compounds cannot be hydrolyzed into smaller carbohydrate units and serve as the basic building blocks for more complex carbohydrates such as disaccharides and polysaccharides. They are typically water-soluble, sweet-tasting, and tồn in all living organisms as a primary source of energy and as metabolic intermediates.

Monosaccharides are characterized by a carbon skeleton that carries multiple hydroxyl groups and a carbonyl group. They are categorized as aldoses, which contain an aldehyde group, or ketoses, which contain a ketone group. The general empirical formula is (CH2O)n, where n is the number of carbon atoms. Common classes include triose (3C), tetrose (4C), pentose (5C), hexose (6C), and heptose (7C). Many monosaccharides exist in both linear and cyclic forms; in solution, cyclic hemiacetals or hemiketals form, leading to anomeric isomerism (alpha and beta forms). They are also chiral, giving rise to D- and L- enantiomers, of which the D- isomers predominate in nature.

Examples include glucose, galactose, and fructose—glucose and galactose are aldohexoses, while fructose is a ketohexose. Monosaccharides are central to metabolism, entering pathways such as glycolysis for energy production, and they participate in the formation of disaccharides (for example, sucrose from glucose and fructose) and polysaccharides (such as starch and cellulose). They also serve as essential constituents of nucleotides and cofactors.