ABSTRACT
Transcription, as described in Chapter 4, results in synthesis of RNA molecules whose nucleotide sequences are set, according to the base-pairing rules, by the sequences of the genes from which they are copied. These RNA molecules can be grouped into two categories, messenger RNA (mRNA) and noncoding RNA. Messenger RNA is transcribed from protein-coding genes and so undergoes the second stage of gene expression, translation. It therefore acts as the intermediate between a gene and its protein product. Noncoding RNA includes a variety of transcripts that do not code for proteins but instead play roles in the cell as RNA molecules. Now we must look at these two types of RNA in more detail, mRNA in this chapter, and noncoding RNA in the next.
