Monossacarídeos

Monossacarídeos, commonly known as simple sugars, are the most basic units of carbohydrates. They cannot be hydrolyzed into simpler compounds. The general formula for a monosaccharide is C_n(H_2O)_n, where n is typically an integer between 3 and 7. The simplest monosaccharides are trioses, with three carbon atoms, such as glyceraldehyde and dihydroxyacetone. Pentoses, with five carbon atoms, include ribose and deoxyribose, crucial components of RNA and DNA, respectively. Hexoses, with six carbon atoms, are among the most biologically important and include glucose, fructose, and galactose. Glucose is the primary source of energy for most cells and is found in blood. Fructose is the sugar found in fruits, and galactose is a component of lactose, the sugar in milk.

Monosaccharides can exist in open-chain or cyclic forms. In aqueous solutions, the open-chain form readily converts to a cyclic hemiacetal or hemiketal structure. They are typically sweet-tasting and soluble in water. Monosaccharides are chiral molecules, meaning they have stereoisomers. The classification of monosaccharides is based on the number of carbon atoms and the type of carbonyl group present. Aldoses contain an aldehyde group, while ketoses contain a ketone group. For example, glucose is an aldohexose, and fructose is a ketohexose. These simple sugars serve as building blocks for more complex carbohydrates like disaccharides (e.g., sucrose, lactose) and polysaccharides (e.g., starch, cellulose).