RNAs as Intermediates in the Flow of Genetic Information Transcription by DNA dependent RNA polymerase RNA processing - pre RNA RNA Translation protein processing polypeptide protein RNAs function in RNA processing: snRNA snoRNA RNAs function in translation: mRNA, tRNA rRNA TRANSLATION - The mRNA sequence is translated into a polypeptide (sequence of amino acids) which is then modified, folded and transported to the cellular compartment where it will assemble with other macromolecules and function as a protein. Nirenberg and Matthei used synthetic mRNA AND an in vitro protein synthesizing extract synthetic mRNA + cell-free extract + radioactive amino acid (one at a time) Poly (U) ~ (UUUUUU) - Phe AAAAAA - Lys CCCCCCC- Proline Some codons were initially ambiguous?