![]() ![]() Transcription is simple to understand as a means of information transfer: since DNA and RNA are chemically and structurally similar, the DNA can act as a direct template for the synthesis of RNA by complementary base-pairing.Genetic code In contrast, the conversion of the information in RNA into protein represents a translation of the information into another language that uses quite different symbols. In eucaryotic cells, the process of transcription is much more complex, and there are three RNA polymerases polymerase I, II, and III-that are related evolutionarily to one another and to the bacterial polymerase.FROM RNA TO PROTEIN An mRNA Sequence Is Decoded in Sets of Three Nucleotides Once an mRNA has been produced by transcription and processing, the information present in its nucleotide sequence is used to synthesize a protein. An mRNA molecule is produced when this enzyme initiates transcription at a promoter, synthesizes the RNA by chain elongation, stops transcription at a terminator, and releases both the DNA template and the completed mRNA molecule. Bacteria contain a single type of RNA polymerase (the enzyme that carries out the transcription of DNA into RNA). ![]() Bases in other configurations are indicated by broken rungs.Review: TranscriptionBefore the synthesis of a particular protein can begin, the corresponding mRNA molecule must be produced by transcription. ![]()
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