1. Initiation: unwind/unwrap the section of the chromosome that contains the gene. RNA polymerase attaches to a promoter sequence. 2. Elongation: RNA polymerase builds the mRNA molecule while using DNA as a template. 3. Termination: RNA polymerase reaches a termination sequence.
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What is a promoter sequence?
An area in the code rich in T and A
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Describe post transcriptional?
Introns are cut out and exons are put together. 5’ cap is added to mRNA so ribosomes can bind. Poly-A tail onto 3’ end to stabilize.
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Describe Translation
1. Assembly: SRS attaches to 5’ cap of mRNA. SRS travels down until a start codon is found. tRNA with MET binds to mRNA. LRS attaches onto complex with 1st tRNA in p-site. The next codon is exposed in a-site. 2. Elongation: next tRNA carries a.an into a-site. Peptide linkages form between a.a in a-site and p-site. A.a in p-site is released from tRNA. tRNA in p-site leaves and the one from a-site with the a.a chain shifts to replace it. Repeat.
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Describe termination
When a stop codon enters the a-site, no tRNA enters. Release factors will enter and the a.a chain releases