Which is older, DNA or RNA?

RNA. We know this because DNA is synthesized from RNA precursors in all known organisms. If DNA was present before RNA we would expect the reverse relationship, especially as it is a much easier chemical reaction. read more

Like DNA, RNA is composed of its phosphate group, five-carbon sugar (the less stable ribose), and four nitrogen-containing nucleobases: adenine, uracil (not thymine), guanine, and cytosine. RNA folding in on itself into a hairpin loop. read more

DNA is a double helix meaning it has two twisted strands that are complementary to each other match up by the base pairing rules while RNA, on the other hand, is only single stranded and created in most eukaryotes by making a complementary strand to a single DNA strand. read more