BIO230H1 Chapter Notes - Chapter 2: Nucleotide, Phosphodiester Bond, Sigma Factor
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BIO230H1 Full Course Notes
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Document Summary
How cells read the genome: from dna to protein. Rna has ribonucleotides (contain sugar ribose rather than deoxyribose) Rna has acg and u instead of t. Transcription produces rna complementary to one strand of dna. Rna chains are not hydrogen bonded to dna molecules. Rna polymerase catalyze the formation of the phosphodiester bond that link the nucleotides together to form a linear chain. Difference between rna polymerase and dna polymerase. Rnap can star transcription without a primer. Because transcription does not have to be as accurate. Proofreading: if incorrect, backup and excision (water replace pyrophosphate and a nucleoside monophosphate is released) Signals encoded in dna tell rna polymerase where to start and stop. Sigma factor + core enzyme = rna polymerase holoenzyme. Slides to detect promoter, bind to open up double helix. Core enzyme break free from bubble, discard sigma factor. Polymerase mose down dna and synthesize rna. Terminator met, rnap stops and release both new rna and dna.
