Strategize a Smooth Tenant-to-tenant Migration and Copilot Takeoff
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Lecture 29
1. 11/14/08
Lecture 29 - Molecular Genetics 4
ï Promoter (regions): regions where RNA polymerase binds.
ï In Eukaryotic cells, promoter contain a sequence of nucleotides called TATA (DNA) box.
ï Transcription factors bind to the promoter before the RNA polymerase can bind.
ï Termination
ï Prokaryotic cells
ï The termination sequence is in the DNA.
ï When RNA polymerase detaches from DNA.
ï The mRNA is released (going to the ribosomes).
ï Eukaryotic cells
ï RNA polymerase continues transcription beyond the coding section of the gene (adding a non-
coding signal, usually being AAUAAA).
ï In the prokaryotic cell, mRNA goes directly to the ribosome.
ï In the eukaryotic cell, two kinds of mRNA exist, pre-mRNA and final mRNA.
ï Pre-mRNA has to be proceeded and edited (all happening in the nucleus) to make final mRNA.
ï - Split genes: many sequences are removed from the pre-mRNA.
ï Introns: the pieces of the mRNA strand that are removed.
ï Exons: the pieces of the mRNA that are used in the final mRNA.
ï Both (5' and 3') ends of the mRNA strand are modified.
ï A modified âguanine capâ is added to the 5' end.
ï A âpoly A tailâ is added to the 3' end.
ï Final mRNA is sent from the nucleus to the ribosome.
ï Translation
ï Transfer RNA (tRNA) is needed for translation.
There are many kinds of tRNA. There is 1 tRNA for each codon; the total is 61 tRNA molecules.
ï An anticodon is attached to the bottom loop of the tRNA molecule.
ï Ribosomes
ï Ribosomes are necessary in prokaryotic and eukaryotic cells.
ï They are where polypeptide chains are assembled.
ï Ribosomes consist of 2 sub-units (large and small)
ï rRNA (ribosomal RNA) consist of RNA and a ribosomal protein