Does DNA have 5 nitrogenous bases? I believe they are 5 because Uracil is not the same thing as Guanine, because, first of all, uracil "replaces" thymine, not guanine. And second, uracil performs a range of functions that go far beyond "replacing" thymines at the time of transcription and translation. Am I right?
It's a bit more complicated than that.
This wiki entry on nucleotides should help clarify things: Nucleotide
I'm not sure what you mean by "...a range of functions..."