The backbone of an RNA molecule is formed by a slightly different sugar from that in DNA—ribose instead of deoxyribose; in addition, one of the four bases is slightly different—uracil (U) replaces thymine (T). Most important, however, the other three bases—A, C, and G—are identical to those in DNA, and all four bases will pair with their complementary counterparts in DNA—the A, U, C, and G of RNA with the T, A, G, and C of DNA, respectively.
