Used_in The definition of C++ [ c++.syntax.html ]. Used_in The definition of Java [ java.syntax.html ] Notation This uses my XBNF Extended BNF Notation where | indicates or, (...) indicates priority. For more information see [ intro_ebnf.html ].
To look at it in another way: Thymine(uracil in RNA) and cytosine are pyrimidines. Pyrimidines are single-ringed organic base that will only attach to purines, or adenine and guanine by hydrogen bond. Because cytosine and thymine are both pyrimidines, it cannot form a hydrogen bond with each other.
1 In DNA, thymine (T) binds to adenine (A) via two hydrogen bonds, thus stabilizing the nucleic acid structures. 2  A DNA molecule is made up of two strands of nucleotides that spiral around each other to form a double helix.he order that the bases appear is insignificant in the DNA molecule. This means that there can be four different cross rungs â adenine with thymine, thymine with adenine, cytosine with guanine, and guanine with cytosine.