RNA, pre mRNA and mRNA
- Ribonucleic acid (RNA) is a single strand molecule made of a slightly different alphabet: Adenine, Guanine, Cytosine and Uracil (AGCU). Comparing to DNA, T is replaced by U.
- Another subtle (and often ignored) difference between RNA and DNA is as the name suggest: ribose vs dioxyribose sugar, there’s an extra -OH group attaching to the ribose ring at carbon 2 for RNA.
- RNA is transcribed from a gene region of DNA following the same pairing rules A-U, C-G.
- pre mRNA & mRNA: preRNA is the photocopy (1:1 mapping A-U, C-G) of the DNA sequence. preRNA goes through splicing processes, where chunks of sequences are deleted and/or rearranged (more on splicing later), resulting in matured/messenger RNA (mRNA).