Bacterial and Eukaryotic Ribosomes Structure
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Questions and Answers

What is the function of the Peptidyl-transferase centre in ribosomes?

  • Match tRNAs to codons
  • Identify the start codon
  • Catalyze formation of peptide bonds (correct)
  • Facilitate complementary base pairing

    • Which RNA molecule is found in both bacterial and eukaryotic small ribosomal subunits?

  • 18S rRNA
  • 16S rRNA (correct)
  • 5S rRNA
  • 23S rRNA

    • In bacterial mRNA, what is the function of the Shine–Dalgarno sequence?

  • Separate translation segments
  • Facilitate complementary base pairing
  • Bind mRNA and identify the start codon (correct)
  • Catalyze formation of peptide bonds

    • What differentiates bacterial and eukaryotic translation initiation processes?

    <p>Positioning of the ribosome on the start codon</p> Signup and view all the answers

    In translation, what does the Decoding centre of ribosomes specifically do?

    <p>Match tRNAs to codons</p> Signup and view all the answers

    Which region of mRNA marks the boundaries of translation and contains the stop codon?

    <p>3' untranslated region (3' UTR)</p> Signup and view all the answers

    What is needed for initiation of translation in bacteria?

    <p>mRNA, small ribosomal subunit, large subunit, initiator tRNA, and initiation factor proteins</p> Signup and view all the answers

    What is the role of IF1 in the initiation of translation in bacteria?

    <p>To prevent the initiator tRNA from going into the incorrect site</p> Signup and view all the answers

    Which sequence base-pairs with the 16S rRNA to position the start codon correctly in bacteria?

    <p>Shine–Dalgarno sequence</p> Signup and view all the answers

    What is the name of the modified amino acid carried by the initiator tRNA during translation initiation in bacteria?

    <p>N-formylmethionine (fMet)</p> Signup and view all the answers

    What happens when the 50S large subunit joins the 30S small subunit during translation initiation in bacteria?

    <p>The union of the two subunits with dissociation of initiation factors</p> Signup and view all the answers

    What is necessary to guide the initiator tRNA into the P site during translation initiation in bacteria?

    <p>IF2</p> Signup and view all the answers

    What is the function of the Shine-Dalgarno sequence in prokaryotic mRNA?

    <p>Finding and positioning the start codon on the ribosome</p> Signup and view all the answers

    What are some proteins involved in recognizing mRNA in eukaryotic translation initiation?

    <p>eIF4E, eIF4G, and PABP</p> Signup and view all the answers

    Which release factor recognizes all three stop codons in eukaryotes and archaea?

    <p>eRF1</p> Signup and view all the answers

    What is the role of eIF1a during translation initiation in eukaryotes?

    <p>Blocking the A site on the ribosome</p> Signup and view all the answers

    Why is the consensus Kozak sequence important in translation initiation?

    <p>Locates the correct start codon on mRNA</p> Signup and view all the answers

    Which antibiotics block elongation step in protein synthesis?

    <p>Erythromycin</p> Signup and view all the answers

    What occurs when a match is found during translation initiation?

    <p>Initiation factor dissociation</p> Signup and view all the answers

    In bacteria, which component recognizes stop codons UAG and UAA?

    <p>RF1</p> Signup and view all the answers

    What does EF-G do during elongation phase of protein synthesis in bacteria?

    <p>Translocates the ribosome along mRNA</p> Signup and view all the answers

    What blocks translocation step in protein synthesis?

    <p>Cycloheximide</p> Signup and view all the answers

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