Sunday 1 March 2015

How Does Transcription occur?



RNA Molecules:
  • mRNA (Messenger) : template for translation
  • tRNA (Transfer) : translation of mRNA
  • rRNA (Ribosomal) : translation of mRNA
  • snRNA (Small unit) : modify mRNA molecule
Key terms:
  • "TATA" Box / Promoter region / Upstream
  • Initiation complex
  • Coding/Sense strand
  • Template / Antisense strand 
  • RNA Polymerase II
  • Uracil
  • RNA Transcript / pre-mRNA
  • Primary RNA
  • Splicing 
  • Spliceosome
  • Intron
  • Extron
  • poly-A-tail
  • G-cap
  • Transcription factor (protein)
  • Ribozyme
  • Terminator / "AAA UAA" / Downstream  



Act 1: Initiation

  • Transcription factors find TATA Box and bind to it. 
  • RNA Polymerase II locates and binds to the transcription factors which create an initiation complex. 
  • RNA Polymerase II begins transcription.
Act 2: Elongation

  • mRNA transcribed in a 5' to 3' direction
  • only one strand is synthesized
  • antiparallel to template strand
  • Copies coding strand but replaces Thymine with Uracil
  • Upstream to Downstream    
Act 3: Termination

  • Terminator sequence signals end point of synthesis of mRNA 
  • stop codon or "AAA UAA"





























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1 comment:

  1. sabrina15 March 2016 at 23:54

    Transcription plays a very important role in protein biosynthesis. The two picture shared here are very enough to express the whole process. Among these process, we can find that the transcription factors are as important as the growth factor for metabolism.

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