monosackarid

Monosackarider, known in English as monosaccharides, are the simplest form of carbohydrates. They are small, water-soluble molecules that cannot be hydrolyzed into smaller carbohydrate units. Most monosaccharides have a carbon chain of three to seven atoms and the general formula (CH2O)n. In solution they typically exist in cyclic forms, although a straight-chain form can be present briefly. They are characterised by multiple hydroxyl groups and a carbonyl group, which is an aldehyde in aldoses or a ketone in ketoses. Monosaccharides are optically active and commonly occur as D- or L-enantiomers, with D- forms predominating in nature.

Classifications of monosaccharides are based on the number of carbon atoms and the position of the carbonyl group. Common categories include trioses, tetroses, pentoses, hexoses and heptoses; aldoses are those with an aldehyde group, while ketoses have a ketone group. Notable examples include glucose, fructose and galactose (six-carbon sugars), as well as ribose and deoxyribose (five-carbon sugars) that are important in nucleic acids.

Biological role and chemistry: monosaccharides serve as building blocks for larger carbohydrates such as disaccharides and polysaccharides, formed through glycosidic bonds. They are central in metabolism, providing quick sources of energy through pathways like glycolysis. Monosaccharides also participate in biosynthetic reactions, and certain sugars such as ribose are essential components of nucleotides.

Occurrence and uses: they occur naturally in fruits, honey, and other plant and animal tissues. Beyond biology, monosaccharides are used in food industry as sweeteners and as intermediates in various chemical syntheses.