MolBioExam5

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  1. TRUE/FALSE. Ribosomes are heteromeric ribonucleo-protein complexes.
    TRUE
  2. TRUSE/FALSE. The initiating tRNA enter the P site of the ribosome.
    TRUE
  3. TRUE/FALSE. The bacterial 23S rRNA interacts with mRNA in the ribosome.
    FALSE
  4. TRUE/FALSE. Besides correct charging of tRNAs w/ AAs the ribosome has no mech for ensuring correct incorporation of AAs into a protein (has no role in fidelity).
    FALSE
  5. TRUE/FALSE. A transcript that's expressed at nearly a constant level is described as being "constitutive."
    TRUE
  6. What domain requires a 5'-cap and polyA-tail on transcripts for efficient translation?
    euks
  7. Does bacteria AND archaea utilize cycles of GTP binding and hydrolysis to catalyze movement of tRNAs and mRNAs w/in ribosome to achieve translation?
    YES!
  8. TRUE/FALSE. Bacteria use a Shine-Delgarno seq to identify start codon.
    TRUE.
  9. In bacteria, the translation initiation complex includes an RNA helicase that cleaves ATP to catalyze disruption of hairpin structure thtatmight block AUG start codon.
    FALSE, this occurs in EUKARYOTES!
  10. TRUE/FALSE. Euks has highly processive translation.
    TRUE 
  11. TRUE/FALSE. Bacteria has highly processive translation.
    TRUE
  12. TRUE/FALSE. Only bacteria have a mech of dealing w/ stalled ribosomes that lack stop codons that relies on a hybrid tRNA-mRNA molecule.
    FALSE! -both bacteria AND euks do ! 
  13. TRUE/FALSE. Bacteria and Euks have operons!
    TRUE
  14. TRUE/FALSE. Bacteria have regulatory sites that can be far upstream / downstream of promoter.
    FALSE! -only euks have reg sites ↑stream or ↓stream of promotoer! 
  15. Which domain has regulatory proteins that loop DNA during regulation of gene expression?
    BOTH, euk & bacteria
  16. Which domain uses nuclear localization as an imp means of regulating activity of TFs? euks or bacteria?
    EUKS! 
  17. Which of the following is a true statment about aminoacyl tRNA synthetase? (+1 answer)
    A. They identify the proper tRNA molecule by reading only the seq of the anticodon. 
    B. They transfer the "activated" aa to the 5'end of the tRNA.
    C. Some, such as the isoleucine tRNA synthetase, using a proofreading site to cleave tRNAs that have been incorrectly charged w/ the non-cognate aa.
    D. they + the aminoacyl group to tRNA after it has entered the ribosome.
    E. They show the expected specificity for charging of tRNAs  w/ the proper aa's based on differences in binding energy of alternative tRNAs / aa's to a signal active site.
    B. They transfer the "activated" aa to the 5'end of the tRNA.C. Some, such as the isoleucine tRNA synthetase, using a proofreading site to cleave tRNAs that have been incorrectly charged w/ the non-cognate aa.
  18. What does the 50S subunit do?
    -this ribosomal subunit catalyzes peptide bond formation.
  19. what factor helps to align the start codon in the P-site during translation initiation?
    IF-3
  20. What has a key role in translation fidelity by catalyzing the specific charging of tRNAs w/ aa's?
    tRNA synthetase
  21. What has the ability to recognize the stop codon during termination of translation?
    RF-1
  22. What is a key role of tRNA synthetase ?
    a key role in translation fidelity by catalyzing the specific charging of tRNAs w/ aa's
  23. What is EF-Tu?
    a protein associated w/ an aminoacylated tRNA as it enters the ribosome during elongation.
  24. What is the cause of EF-G?
    causes translocation of mRNA w/in ribosome using GTP hydrolysis
  25. What causes translocation of mRNA w/in ribosome using GTP hydrolysis?
    EF-G
  26. Which subunit is where the tRNA directly interacts w/ the mRNA?
    30S subunit
  27. 30S subunit is where what interacts?
    where tRNA directly interacts w/ mRNA
  28. what rescues stalled bacterial ribosomes?
    tmRNA
  29. What does tmRNA do?
    rescues stalled bacterial ribosomes!
  30. Lists the proteins/molecules properly ordered as they participate in translation in E.coli.
    • tRNA synthetases 
    • IF3
    • 50S subunit
    • EF-Tu
    • suppressor tRNA 
    • RF1
  31. Which of the following prevents activators 4rm interacting w/ incorrect promoter?
    A. Mediator 
    B. Architectural enhancer
    C. Corepressor
    D. Insulator
    D. Insulator
  32. TRUE/FALSE. in euk transcription, the default state is OFF due to presence of nucleosomes that can block promoter access.
    TRUE
  33. Which of the following statements is incorrect of euk transcription? (+1 answer)
    A. default state = OFF due to presence of nucleosomes that block promoter access.
    B. default state = ON due to presence of nucleosomes that are arranged for binding of TF's.
    C. default state = OFF due to presence of centromeres and centromere binding proteins.
    D. dafault state = OFF due to action of diverse, specific transcriptional repressors encoded in euk genomes.
    • B. default state = ON due to presence of nucleosomes that are arranged for binding of TF's.
    • C. default state = OFF due to presence of centromeres and centromere binding proteins.
    • D. dafault state = OFF due to action of diverse, specific transcriptional repressors encoded in euk genomes. 
  34. When homologous recombination is not an option, researchers can accomplish reduction of expression of a plant / lower animal gene by introducing an inverted repeat DNA molecule into cell that when transcribed forms a long dsRNA. Normally, organisms use this for protection against viruses & for shutting down endogenous expression of repeat-rich elements aka transposons, retrotransposons, and centromeres. The imp functional molecule in this "gene silencing" is called
    A. a riboswitch
    B. a 3'UTR binding element 
    C. a protein kinase
    D. an siRNA
    E. a transcriptional inhibitor
    D. an siRNA 
Author:
mnvang321
ID:
313272
Card Set:
MolBioExam5
Updated:
2015-12-15 21:38:58
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MolBio
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MolBioExams
Description:
Exam 5
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