Notes for 10/22/07Transcription in ProkaryotesOverview:The genetic information in a gene is copied into RNA by the enzyme RNA polymerase. This process is known as transcription. During transcription, only one strand of the DNA is used as the template, and the nucleotides ATP, GTP, CTP, and UTP are used as substrates. The RNA molecule is synthesized from the 5’ to 3’ direction, and the template strand is read 3’ to 5’. RNA polymerase starts transcribing the template from a specific site near the beginning of the gene. (We refer to this end of the gene as the 5’ end because it produces the 5’ end of the RNA). Likewise RNA polymerase stops or terminates transcription at a specific site at the other end of a gene (the 3’ end). Transcription consists of three stages: initiation, elongation, and termination. In class, we will discuss, in detail, what happens during initiation and termination.Important terms to remember: Holoenzyme: with 5 polypeptides; 2 at alpha, and 1 each at beta, beta’ and sigma.
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