Sunday, 1 March 2015

Initiation, Elongation, and Termination of Transcription

Initiation: 
Main 'characters': Transcription factors, promoter region (TATA box), polymerase 2 
-Transcription Factors (TFs) bind to the promoter region (eukaryotes need other proteins to recruit polymerase) 
-TATA box (found upstream) is the site to bind for TFs 
-Once binding is complete, poymerase 2 begins to read TF and transcribes on a complementary strand 

Elongation:
Main 'characters': Polymerase 2, coding strand, template strand 
-Elongation in transcription also occurs in a 5' to 3' direction 
-The strand that is very similar to the RNA transcript is the coding/sense strand (the opposite is the template/antisense strand) 
-RNA is anti parallel to the templat/antisense strand 
-During transcription, Thyamine (T) is replaced by Uracil (U) (Love U and not T(ea))

Termination: 
Main 'characters': AAAUAAA, intron, exon, G-cap and poly-a tail
-Transcription stops when polymerase 2 reaches the terminator AAAUAAA(downstream) 
-pre mRNA can't be sent into the cytoplasm (water=oxygen filled; oxygen=bully)
-G-cap and poly A-tail put on ends of the strands to protect from bullies
-intron=junk DNA to be cut out



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