RNA Processing

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)
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
Name the single RNA polymerase for prokaryotes

alpha2beta.beta’ omega.sigma
if there are 10 loops, how many exons are present in the gene?
- 10+1=11
- take number of loops which are introns and add one to get the number of exons
Define Splicing

–The process by which introns are removed from the hnRNA (heterogeneous RNA) to produce mRNA
Where do you find introns?
- found in : genomic DNA
- primary transcript (hnRNA) heterogeneous RNA
- rRNA
- tRNA
- not found in : mature mRNA (or in cDNA)
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

Author

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51673

Card Set

RNA Processing

Description

cell bio

Updated

2010-11-26T00:29:30Z

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