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18 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What catalyses transcription of all kinds of RNA in bacteria? |
RNA polymerase |
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Initiation |
RNA binds to promoter and initiates transcription |
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Substrate |
Nucleoside Triphosphate |
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Opening of helix and elongation done by? |
RNA polymerase (unzipping) |
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Termination x |
Polymerase reaches terminator and nascent RNA falls off |
How does RNA polymerase catalyse all three steps? |
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How does RNA polymerase catalyse all three steps? |
It only catalyses elongation - teams up with initiation factor sigma and termination factor rho |
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What do the factors do? |
Alter polymerase specificity to either initialize or terminate |
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Why can translation begin in bacteria b4 mRNA fully transcribed? |
No processing of mRNA, transcription and translation take place in same compartment (no separation of cytosol and nucleus in bacteria) |
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In eukaryotes, how many RNA polymerase total? |
4 (3 nucleus +1 organelle) |
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RNA POLYMERASE 1 TRANSCRIBES |
rRNA - 28 S, 18 S, 5.8 S |
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RNA polymerase 2 |
Precursor of mRNA - heterogeneous nuclear RNA (hnRNA) |
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RNA polymerase 3 |
tRNA, 5S rRNA and snRNA {small nucleus) |
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Splicing |
Introns removed, exons joined in defined order |
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HnRNA processing |
Tailing and capping |
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Capping |
Unusual nucleotide - methyl guanosine Triphosphate) added to 5' end of hnRNA |
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Tailing |
Adenylate residues (200 - 300) added to 3' end in template independent manner |
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HnRNA after capping and tailing |
MRNA - transported out of nucleus for translation |
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Introns |
Ancient feature - remnants of RNA world |
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