Deoxyribose, a pentose sugar derivative found in all cells, is an important part of DNA, as explained below. Deoxyribose is a pentose sugar derivative found in all cells, and is a sugar in which the number of hydrogen atoms in the molecule does not correspond to the number of oxygen atoms in the molecule 2:1. Deoxyribose is one of the important five-carbon sugars, with aliases such as D-deoxyribose, 2-deoxy-D-ribose, and thymose. Deoxyribose DNA is a long chain of many deoxyribonucleotide residues linked to each other in a certain order by 3′, 5′-phosphodiester bonds. Most DNA contains two such long strands, but some DNA is single-stranded, such as E. coli, phage, etc. Some DNA is circular, some is not. Some DNA is circular and some is linear. The base composition of DNA varies from species to species, but the number of adenines in it is equal to the number of thymines in it, and the number of guanines is equal to the number of cytosines in it.D-2-deoxyribose is a derivative of ribose in which one of the hydroxyl groups at the 2-position has been replaced by a hydrogen group . It is important in cells as a component of deoxyribonucleic acid DNA.