The elements are: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P) and Sulfur (S).
The letters stand for the following bases:
All these bases are nucleobases and classified as purine (A and T) or pyrimidines (C, G and U). The purines are five and six membered heterocyclic compounds, while the pyrimidines are six membered rings.
A forms hydrogen bonds only with T, while C forms hydrogen bonds with G only.
DNA contains A, T, C and G; while the RNA contains, A, U, C and G. In other others, uracil replaces thymine in RNA.
The 'NA' in DNA and RNA stands for nucleic acid.
DNA stands for deoxyribonucleic acid and the RNA stands for ribonucleic acid. RNA and DNA are one of the major classes of macromolecules found in our body.
Hope this helps.