nucleic acid deoxyribonucleic acid 2012-10-16T02:22:54Z A long, polymeric chain of alternating phosphate and deoxyribose units with the bases adenine, guanine, cytosine, and thymine bonded to the deoxyribose. DNA can be single stranded or double stranded, that is, composed of either a single polymer or a pair of antiparallel polymers joined by hydrogen bonding between complementary bases. DNA XCO:0000234 experimental_condition_ontology jsmith