Chapter 23 - RNA and Protein Synthesis

Abstract

The information for making proteins resides in the sequence of bases in the DNA. Converting the information contained in genes into proteins involves two complex processes. Transcription is the first step in which the sequence of bases in a gene is converted into a complementary sequence of bases in a molecule of RNA. Three chemically similar but functionally quite different types of RNA work together to convert the sequence of bases in DNA into the sequence of amino acids in a protein: messenger RNA (mRNA) carries the genetic information contained in a gene; transfer RNA (tRNA) and ribosomal RNA (rRNA) are also transcribed from genes but are used to convert the information in the sequence of bases in an mRNA molecule into the corresponding sequence of amino acids in a protein. Translation is the process by which an mRNA is “read” by tRNAs, ribosomes, and numerous enzymes. Many other species of RNA have been identified and shown to be involved in many regulatory and catalytic roles in cells. These RNAs include small interfering RNA (siRNA), microRNA, piwi-interacting RNA (piRNA), and small nuclear RNA (snRNA).