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.
Monoamines and catecholaminesânotes on molecular structure: Monoamines: The major neurotransmitters we will discuss here (serotonin, dopamine, norepinephrine, and epinephrine) are all monoamines. Monoamines contain one amino group that is connected to an aromatic ring by a two-carbon chain (-CH2-CH2-).