Is DNA the only nucleic acid molecule?
No, there is another type of nucleic acid called ribonucleic acid, or RNA. RNA, like DNA, is made of nucleotides. The sugar of RNA is slightly different than the one found in DNA; this difference accounts for the names of the two molecules (deoxyribose versus ribose). One of the bases in DNA, thymidine, is substituted by a different base, uridine (U) in RNA. Unlike the large double-stranded DNA, RNA molecules have only one strand and are generally smaller. RNA can be thought of as an intermediate in the decoding of DNA into protein; genes in DNA are copied into an RNA molecule through a process called transcription and the RNA is then decoded (translated) into amino acids that make a protein.
