RNA Processing

  1. 5’ Capping - 3 Enzymes
    • 1. phosphatase - removes 5’ phosphate
    • 2. guanyl transferase - adds GMP by 5’ to 5’linkage
    • 3. methyl transferase - adds methyl group to guanosine (also adds methyl groups to 2’ hydroxyloxygen of bases 1 and 2)
  2. Name the Three Different RNA Polymerases for
    eukaryotes and their different functions
    RNA polymerase I for class I gene (rDNA) transcription to synthesize rRNA

    RNA polymerase II for class II genes (protein coding genes) to synthesize mRNA

    RNA polymerase III for class III genes (tRNA genes and small RNA genes) to synthesize tRNA and small nuclear RNAs
  3. Name the single RNA polymerase for prokaryotes
    alpha2beta.beta’ omega.sigma
  4. if there are 10 loops, how many exons are present in the gene?
    • Image Upload 2
    • 10+1=11
    • take number of loops which are introns and add one to get the number of exons
  5. Define Splicing
    –The process by which introns are removed from the hnRNA (heterogeneous RNA) to produce mRNA
  6. Where do you find introns?
    • found in : genomic DNA
    • primary transcript (hnRNA) heterogeneous RNA
    • rRNA
    • tRNA
    • not found in : mature mRNA (or in cDNA)
  7. Pre-mRNA processing in eukaryotes – 4 Steps
    1. Transcription, 5’ capping

    2. Endonuclease cleavage at polyA site

    3. Poly(A)Polymerase (PAP) Polyadenylation

    4. RNA splicing
Card Set
RNA Processing
cell bio