Biol 118 1st Edition Lecture 15 Outline of Last Lecture I Introduction II Gene Expression III What Do Genes Do IV The One Gene One Enzyme Hypothesis V The Central Dogma of Molecular Biology VI RNA The Intermediary Between Genes and Proteins VII The Central Dogma VIII The Roles of Transcription and Translation IX Exceptions to the Central Dogma X The Genetic Code XI How Long Is A Word in the Genetic Code XII What is a Codon XIII Cracking the Genetic Code XIV Important Properties of the Code XV Using the Code XVI What is the Molecular Basis of Mutation XVII Mutations Have Varying Effects on Organisms XVIII Chromosome Mutations Outline of Current Lecture I Introduction How Cells Build Protein II Overview of Transcription III What Role Does Sigma Play in Initiation IV Bacterial Promoters Current Lecture Introduction How cells build protein A cell builds the proteins it reads o From instructions encoded in genome Overview of Transcription The first step in converting genetic information into proteins is transcription o Synthesis of mRNA version of the instructions stored in DNA RNA polymerase performs the synthesis by transcribing only one strand of DNA These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o Called the template strand The other DNA strand is called the non template or coding strand o Matches the sequence of mRNA o Except RNA has Uracil U instead of thymine T What Role Does Sigma Play in Initiation Sigma and RNA Polymerase together to form a holoenzyme o An enzyme made up of a core enzyme o And other required proteins Prokaryotic RNA polymerase is a holoenzyme o Made up of the core enzyme and a sigma subunit o Has the ability to synthesize RNA Sigma acts as a regulatory factor o Guiding RNA polymerase to specific promoter sequences on the DNA strand Bacterial Promoters Bacterial promoters o Are comprised of 40 50 base pairs o Have two key regions 10 box 35 box 10 box o Is found 10 bases upstream from the transcription start site 1 site o Consists of sequence TATAAT 35 box o Is 35 base pairs upsteam from 1 site
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