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5.2 Eukaryotic Translation — Test 1
Q1. Aminoacyl-tRNAs are escorted to the ribosomal A site by the elongation factor:✓ EF-Tu (eEF1A in eukaryotes)
Q2. Erythromycin inhibits protein synthesis by:✓ Binding the 50S subunit and inhibiting translocation/exit-tunnel
Q3. Eukaryotic RNA polymerase I:✓ Is in the nucleolus and makes pre-rRNA
Q4. In the standard mitochondrial genetic code, which is a stop codon that differs from the standard code (AGA/AGG as stops in mammals)?✓ AGA (a stop in mammalian mitochondria)
Q5. Protein synthesis in eukaryotes is specifically inhibited by:✓ Cycloheximide
Q6. The protein-synthesis inhibitor specific to eukaryotes vs prokaryotes pairs as:✓ Cycloheximide (eukaryotic) vs chloramphenicol (prokaryotic)
Q7. Removing RNA polymerase III from the nucleoplasm would most directly reduce synthesis of:✓ tRNA (and 5S rRNA, U6)
Q8. The mammalian mRNA sequence around the start codon, 5'-(gcc)gccRccAUGG-3', is called the:✓ Kozak sequence
Q9. Which statement about mitochondrial translation is correct?✓ Initiation uses N-formylmethionine (like bacteria)
Q10. Which inhibitor blocks protein synthesis in BOTH bacteria and eukaryotes?✓ Puromycin
Q11. Which statement about eukaryotic translation is NOT true?✓ The initiator tRNA is fMet-tRNA (formylated)
Q12. At the end of initiation, the initiator Met-tRNA is positioned in the ribosomal:✓ P site
Q13. The eukaryotic translocase (moves the ribosome along mRNA) is:✓ eEF2
Q14. Eukaryotic cap-dependent initiation begins with recognition of the 5' cap by:✓ eIF4E (part of eIF4F)
Q15. After the cap is bound, the 40S subunit locates the start codon by:✓ Scanning from the 5' end until the first good-context AUG
Q16. The eukaryotic ribosome is composed of which subunits?✓ 40S + 60S = 80S
Q17. eIF2, in its GTP-bound form, delivers which component to the 40S subunit?✓ The initiator Met-tRNAi
Q18. Diphtheria toxin inhibits eukaryotic translation by:✓ ADP-ribosylating and inactivating eEF2
Q19. Termination in eukaryotes is mediated by the release factor that reads all three stop codons:✓ eRF1 (with eRF3)