A set of two bonded nucleotides on opposite strands of DNA. There are two possible base pairs: C-G and A-T.
Pairs of complementary nitrogenous bases that interact to form each rung of DNA's double helix. Adenine (A) pairs with thymine (T); cytosine (C) pairs with guanine (G).
The length of a piece of DNA is often referred to in terms of how many base pairs are present in it. For example, the piece below would be 6 base pairs long (the dotted lines represent the sugar-phosphate backbones of the DNA).------------ A T C G C A | | | | | | T A G C G T