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18 Cards in this Set
- Front
- Back
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The ternary complex of eIF2-GTP & tRNAi^Met, the 40S subunit and eIF3 and eIF1a form what?
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The 43S pre-initation complex.
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You don't want to translate proteins if you are nutrient deficient. At which point in translation is the regulatory step? Which protein mediates it?
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The eIF2-GTP factor. Guanine Exchange Proteins (GEFs) mediate it; swapping in a GDP inactivates the complex.
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What is the purpose of the eIF4-B?
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Positions eIF4A so that is can perform its helicase activity.
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Does the "scanning" performed by eIF4A require ATP or GTP?
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ATP.
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When are the eIFs released? How are they released?
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After all the eIFs 1-4 as well as the mRNA have been recruited. GTP hydrolysis in eIF2-GTP induces release of the eIFs.
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True or False: The hydrolysis of eIF3 causes the eIFs to dissociate from the initiation complex.
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False..
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Which factor induces the recruitment of the 60S subunit?
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eIF5-GTP
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Which eIFs in eukaryotes have GTP binding capibility?
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eIF2, eIF5
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True or False: eIF2-GTP binds to the tRNAi^Met.
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true. .
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List the Elongation Factors (EFs) with GTP binding capability.
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EF1 & EF2
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True or False: A ternary complex of tRNA^aa, EF2 and GTP enter the A site.
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False.
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Describe the ternary complex which enters the A site of the ribosome.
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EF1alpha, GTP and tRNA^aa.
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True or False the hydrolysis of GTP transfers the amino acid from the P site tRNA to the A site tRNA.
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False.
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What does GTP hydrolysis of EF1alpha do?
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Induces a conformation in the ribosome bringing the P & A site tRNA^aa's closer together.
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Which rRNA is responsible for the amino acyl transferase (peptidyltransferase)?
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The large rRNA of the large ribosomal subunit.
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What does EF2-GTP do?
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"Ratchets" the ribosome forward three nucleotides.
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The hydrolysis of which EF kicks out the uncharged tRNA at the E site?
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EF1-alpha-GTP
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True or False: The large rRNA of the large subunit has peptidyltransferase activity which an amino acid from the A site to the P site.
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FALSE!!! peptidyl transfer is from the P site tRNA to the A site tRNA.
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