Definition of base pairing

The specific association between two complementary strands of nucleic acidsthat results from the formation of hydrogen bonds between the base components of the nucleotides of each strand: A=T and GC in DNA, A=U and GC (and in some cases GU) in RNA (the lines indicate the number of hydrogen bonds). Single-stranded nucleic acid molecules can adopt a partially double-stranded structure through intrastrand base pairing. See also nucleosides.