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24 Cards in this Set
- Front
- Back
prokaryotic genes are usually what? |
colinear |
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Prokaryotes order of events |
DNA>mrNA>poly peptide chain, or
transcription>tranlsation |
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eukaryotic genes contain these kind that dont code for anything |
noncoding introns |
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major types of introns |
group 1, group 2, nuclear pre-mrna, trna |
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group 1 and group 2 introns both have what splicing mechanism? |
self-splicing |
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nuclear-premrna has what splicing mechanism? |
spliceosome |
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trna has what splicing mechanism? |
enzymatic |
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location of group 1 intron |
genes of eubacteria, and bacteriophages |
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location of group 2 introns |
genes of eubacteria and eukaryotes |
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location of nuclear premrna intron |
protein encoding genes in the nucleus of eukaryotes |
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location of trna intron |
trna genes of eubacteria and eukaryotes |
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describe the mrna sequence for prokarytoes |
it has a 5' UTR, a Protein coding region, and a 3'UTR. protein coding region has a start codon and a stop codon shine dalgarno sequence is in the 5'UTR |
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describe the mrna structure for eukaryotes |
a 5' cap, protein coding sequence, and poly A tail |
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4 post transcriptional modifications to mrna in eukaryotes |
addition of 5' cap, 3' cleavage and addition of poly a tail, RNA splicing, RNA editing |
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function of 5' cap |
increases mrna stability, enhances rna splicing, helps binding of ribosome to 5' cap, required for nuclear exportf |
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function of poly a tail |
increase mrna stability, helps binding of ribosome to mrna, required for nuclear export |
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function of RNA splicing |
removes noncoding introns from premrna, allows for multiple proteins to be produced through alternative splicing |
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function of RNA editing |
alters nucleotide sequence of mrna |
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5' cap addition |
occurs cotranscriptionally, capping enzyme is recruited to promoter by rna polymerase II, required for nuclear mrna export, protects mrna from exonucleases |
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3' poly A tail addition |
50-200 adenine nucleotides added to the end of mrna transcript, required for nuclear export and mrna stability, cleavage and poly adenlyation, occurs co transcriptionally, may serve as transcription termination signal for rna pol II |
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splicing machinery recognizes what two junctions? |
5' GU and 3' AG junctions of introns |
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pre-mrna exon, intron: and the junctions and branchpoint |
sexon, 5' GU junction, intron (branchpoint A), 3'AG junction, exon |
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splicing overview |
at the 5' splice site of exon 1, it is cut, and attached to the branch point A. Then the 3' splice site is cut, and the molecule is released as a lariat, and the 2 exons are ligated together |
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transesterification reactions are central to splicing |
asd |