Pentoses are a type of simple sugar, or monosaccharide, that contain five carbon atoms. They play a crucial role in various biological processes, including the synthesis of nucleotides, which are the building blocks of DNA and RNA. Common examples of pentoses include ribose and xylose. In addition to their role in genetics, pentoses are also involved in the pentose phosphate pathway, a metabolic pathway that generates NADPH and ribose-5-phosphate. This pathway is essential for cellular processes such as fatty acid synthesis and the production of nucleotides, highlighting the importance of pentoses in cellular metabolism.