Q. Do the phosphate and the pentose groups give heterogeneity or homogeneity to the nucleic acid chains? What about the nitrogen- containing groups? Supported by that, which of those groups is expected to directly participate in the highly heterogeneous and diverse genetic coding, i.e., which of those groups is the foundation of the information for protein production?
The phosphate and the pentose groups are the same in each nucleotide that forms the nucleic acid and as a result they give homogeneity to the molecule. The nitrogen-containing bases however can vary among adenine, cytosine, thymine, guanine (in DNA) and uracil (in RNA). These variations offer the heterogeneity of the nucleic acid molecule.
Homogeneous portions of a molecule seldom would store any information, by the same reason that a sequence of the same letter of the alphabet cannot make many words with dissimilar meanings. The nitrogen-containing bases, on the other hand, because they are different (four different types for DNA or RNA), can make different combinations and sequences that allow the diversity of the genetic code.