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BERG/STRYER VI STUDY GUIDE CHAPTER 29 1. HOMEWORK 1, 2, 3, 6, 18. Understand the "overview" and know the five items on page 823. We will mostly learn about prokaryotic transcription. The promoter site has a "–35" region and also a sequence centered around –10 called a " Pribnow Box " (Fig 29.4). Both are shown at the top of 825. The promoter is found only in the DNA, and is not transcribed. The RNA Pol holoenzyme, including the σ (sigma) subunit as well as α 2 ββ ' must be present for transcription to start. The beta subunit contains the polymerase active site. Sigma is only present during initiation and then drops off. The first base transcribed is always a purine, so new unprocessed RNA always starts with pppA or pppG. The elongation phase does not require an ATP driven helicase, because the " transcription bubble " (about 17 base pairs) travels along with the enzyme, and the energy from re-annealing of DNA strands balances the energy to pull the strands apart (828). RNA Pol can add about 50 nucleotides per second. Understand that the
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This note was uploaded on 05/09/2008 for the course MOLBIO 315 taught by Professor Deis during the Spring '08 term at Rutgers.

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