Organisms from all six kingdoms have DNA but some are not enclosed inside the nucleus but scattered in the cytoplasm.Only eukaryotes have nuclei where DNA strands are enclosed.
Structurally, DNA and RNA are nearly identical. As mentioned earlier, however, there are three fundamental differences that account for the very different functions of the two molecules. RNA has a ribose sugar instead of a deoxyribose sugar like DNA. RNA nucleotides have a uracil base instead of thymine.
