BIOB10Y3 Lecture Notes - Pribnow Box, Transcription Bubble, Sigma Factor
Document Summary
The relationship b/w genes and proteins was demonstrated by experiments done by beadle & tatum in 1940s. They hypothesized that if the dna of this organism were damaged in some way, certain genes may be mutated. We now know that we can"t just go simply from a gene to make a protein. We require an intermediate known as messenger rna (mrna) The process of making this mrna from dna (genes) is called transcription: carried out by dna-dependent rna polymerases, carried out in the nucleus. Transcription (or the synthesis of rna from dna) is a cyclic process and can be broken down into 3 stages: Rna polymerase binds a region of dna close to the beginning of a gene known as a promoter sequence. Polymerase binds to promoter sequence in duplex dna [closed complex] Polymerase melts duplex dna near transcription start site, forming a transcription bubble [open complex] Polymerase catalyzes phosphodiester linkage of two initial rntps: elongation.
