RNA Structure & Function

  1. Biological roles of RNA (4)
    • Storage of genetic information
    • Transmission of genetic information
    • Catalysis and structural components of large macromolecules
    • Gene regulation
  2. Polycistronic
    • Contains information for more than one polypeptide chain
    • Prokaryotic mRNA is polycistronic
  3. rRNA
    Catalytic site of the ribosome
  4. Prokaryotic promoter
    • Directs gene transcription
    • Located "upstream" of coding sequence
    • Both -35 and -10 elements
  5. Topoisomerase
    Eliminates positive supercolis
    • Much more complex than prokaryotic RNA polymerase
    • Requires several transcription factors
    • Rate modulated by enhancers which are located up or down stream and bind specific transcription factors
  7. Eukaryotic DNA-directed RNA Synthesis Initiation
    • Requires binding of transcription factors and RNA polymerase to promoter sites upstream of the coding region of a gene
    • Facilitated by transcription factors bound to enhancer sequences at sites far from the gene
  8. Eukaryotic DNA-directed RNA Synthesis Elongation
    • Requires local unwinding of DNA helix by RNA polymerase
    • Followed by synthesis of a 5'-3' RNA transcript coded for by the DNA template read in the 3'-5' direction
  9. Eukaryotic DNA-directed RNA Synthesis Termination
    • Requires a termination sequence
    • Results in release of RNA polymerase
  10. Eukaryotic mRNA processing (3)
    • 5' capping
    • intron splicing
    • 3' polyadenylation
  11. 5' cap structure
    7-methyl guanosine
  12. Introns
    • Non-coding intervening sequences of RNA
    • Snipped out in spliceosomes, which is composed of small nuclear RNA's and ribonucleoproteins
  13. Alternative splicing
    Image Upload 1
  14. Reverse transcriptase
    • RNA dependent RNA polymerase
    • AND
    • RNA dependent DNA polymerase
Card Set
RNA Structure & Function
RNA Structure & Functiobn