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27 Cards in this Set
- Front
- Back
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In the elongation cycle, what does the factor EF1 alpha-GTP do? How?
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Kicks out the uncharged tRNA in the E site. Also induces conformation change in the ribosome to place 3' ends of tRNAs closer together.
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Which rRNA carriers out the aminoacyl transferase activity? (Hint: which subunit does it occur in?)
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Large rRNA (28S in eukaryotes and 23S in prokaryotes)
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How can you prove that the large rRNA in the large subunit is responsible for aminacyl transferase activity?
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Purifying the large rRNA in vitro shows that it is all that is needed for the enzymatic activity.
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Which factor "ratchets" the ribsome exactly three nucletides along the mRNA?
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EF2-GTP.
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TRUE or FALSE: The termination factors eRF1 and eRF2 contain anticodons!
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False! They have protein domains which recognize the stop codon.
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eRF1 and eRF2 both recognize the stop codon ____. Which ones do they uniquely recognize?
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UAA. eRF1 specific for UAG. eRF2 specific for UGA.
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TRUE or FALSE : There is NO base pairing between any of the release factors and the stop codons?
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True.
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Would all termination halt if the Eukaryotic Release factor eRF1 wasn't functioning? Explain.
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No, It wouldn't because there is another eRF2 would still be capable of recognizing stop codons. (UAA and UGA).
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Explain the effects of hydrolysis of eRF3-GTP.
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Cleavage of the bond between the last a.a. and P-site tRNA would occur. Ribosome would dissociate.
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TRUE or FALSE: The ineffective translation of PAB1 would have no effect on the translational efficiency of other mRNAs. Justify your answer.
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FALSE. It stabilizes mRNA in a pseudo-circle. Interacts with eIF4-G to confer circular orientation.
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What is the primary purpose of the cytoplasmic protein PAB1?
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Prevents/Delays degradation of the poly-A tail of mRNA by blocking nucleases trying to chew mRNA up.
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True or False: In human mRNA degradation, 5' to 3' exonucleolytic digestion can occur.
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True. However, first the poly-A tail must be shortened by an exonuclease.
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What are the pathways which can result from Deadenylation-dependent pathways?
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Decapping & digestion and 3' to 5' exonucleolytic decay.
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Name the three pathways in which mRNA can be degraded.
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Decapping, Deadenylation, and Endonucleolytic pathways.
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What is a nonsense mutation?
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When a mutation occurs, developing a premature STOP codon (UAA UAG UGA)
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Nonsense mutations may result in _______, which will express certain domains but not other, crucial ones in proteins.
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Dominant Negative Fashion.
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How are exons defined on the mRNA?
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SR proteins, which bind to introns and ligands.
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SR proteins are ________ and _____ rich.
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Arginine and Serine rich.
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During which process does the cell recognize an mRNA need to undergo Nonsense Mediated Decay?
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The pioneering 1st round of translation.
Early STOP codons mean that factors loaded onto the mRNA after them will not be removed. <--- giveaway. |
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Why do proteins fold?
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To achieve lowest energy conformation.
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How and why do protein aggregates occur?
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Shortly after translation, proteins may undergo hydrophobic interactions other proteins. These are hard to do.
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Pick the enzyme activity or function Heat Shock Proteins doesn't have: DnaK, ATP-binding ability, and Helicase.
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Helicase.
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In HSP70, what induces the formation of the hydrophobic pockets in which proteins can safely fold?
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Hydrolysis of ATP.
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Which protein is a chaperonin? Or are both? Heat Shock Protein 70 or GroEl?
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GroEL. Found in E.Coli.
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What does GroES contribute to protein folding?
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Its association with ATP and subsequent hydrolysis results in relaxing the GroEL so the folded protein can leave the "barrel".
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True or False: In alzheimer's or Huntington's patients, which proteins could you reasonably guess they're deficient in? GroEL. TriC, HSP70,
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Any proteins responsible for preventing protein plaque aggregates (Chaperones and Chaperonins)...All but GroEL, which is a chaperonin for E.Coli.
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What are the indication, dosage, and administraion pearls for Calcium Chloride?
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1. Indications
Known or suspected hyperkalemia(renal failure). Hypocalcemia(after multiple blood transfusion. Antidote for Calcium Channel Blockers or Beta blocker overdoses. 2. Dosage 8-16mg/kg for hyperkalemia and CCB overdoses. 3. Admin DON"T GIVE WITH HCO3(bicarb) |
