Pentooses

Pentooses are a class of monosaccharides, which are simple sugars, containing five carbon atoms. The name "pentose" is derived from the Greek word "pente," meaning five, and the suffix "-ose," commonly used for sugars. As monosaccharides, pentoses cannot be broken down into simpler carbohydrates by hydrolysis.

The general formula for pentoses is C5H10O5. Like other monosaccharides, they contain hydroxyl (-OH) groups and a carbonyl group (either an aldehyde or a ketone). Depending on the position of the carbonyl group, pentoses can be classified as aldopentoses or ketopentoses. The most common aldopentose is ribose, and its isomer, deoxyribose, is a fundamental component of DNA. Other important aldopentoses include xylose and arabinose, which are found in plant cell walls as part of hemicellulose and pectin. Ribulose and xylulose are examples of ketopentoses, playing roles in metabolic pathways such as the Calvin cycle in photosynthesis.

Pentoses are important in biological systems. Ribose is a crucial component of RNA, ATP (adenosine triphosphate), and various coenzymes like NAD and NADP. Deoxyribose is unique to DNA, forming the sugar-phosphate backbone. While less abundant than hexoses (six-carbon sugars) like glucose, pentoses are essential for genetic material, energy transfer, and structural components in living organisms. Their study is vital in biochemistry and molecular biology.