Monosakkaridiyksiköt

Monosakkaridiyksiköt, also known as simple sugars, are the fundamental building blocks of carbohydrates. They are organic compounds composed of carbon, hydrogen, and oxygen, typically with the empirical formula (CH2O)n, where n is usually between 3 and 7. The term "monosaccharide" literally means "one sugar." These molecules cannot be broken down into simpler carbohydrates by hydrolysis.

The simplest monosaccharides are trioses, with three carbon atoms. Pentoses, with five carbon atoms, are crucial components of nucleic acids (ribose and deoxyribose). Hexoses, with six carbon atoms, are the most common and include glucose, fructose, and galactose. Glucose is the primary source of energy for most organisms. Fructose is known as fruit sugar, and galactose is found in milk.

Monosaccharides can exist in linear or ring forms. In aqueous solutions, the ring form is more stable due to the intramolecular reaction between a carbonyl group and a hydroxyl group. The ring form is typically a furanose (five-membered ring) or a pyranose (six-membered ring). The carbon atom bonded to both the oxygen in the ring and the external oxygen atom (in the hemiacetal or hemiketal group) is called the anomeric carbon. This anomeric carbon gives rise to alpha (α) and beta (β) anomers depending on the orientation of the hydroxyl group.

Monosaccharides are sweet-tasting and are soluble in water. They are important in biological processes, serving as energy sources, components of structural molecules, and intermediates in metabolic pathways. They can be linked together to form disaccharides, oligosaccharides, and polysaccharides.