RR9-11 bio 200 (this one is good)
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What is the primary purpose of 5' capping during mRNA processing?

  • To remove introns from the pre-mRNA
  • To enhance transcription rates
  • To protect mRNA from degradation and aid in ribosome binding (correct)
  • To facilitate RNA splicing

    • Which step in mRNA processing involves the addition of a poly(A) tail?

  • 5' Capping
  • Transcription termination
  • 3' Cleavage and Polyadenylation (correct)
  • RNA Splicing

    • What is the role of RNA splicing in mRNA processing?

  • To remove non-coding regions (introns) and join coding regions (exons) (correct)
  • To attach the 5' cap to the pre-mRNA
  • To facilitate the transcription of DNA into RNA
  • To remove exons and retain introns

    • What happens during the 3' cleavage step of mRNA processing?

    <p>The pre-mRNA is cleaved and a poly(A) tail is added at the 3' end</p> Signup and view all the answers

    Why are modifications at the 5' and 3' ends of pre-mRNA crucial?

    <p>They provide mRNA stability and protection from degradation</p> Signup and view all the answers

    What is the role of serine 2 phosphorylation in relation to the C-terminal domain?

    <p>It recruits additional proteins necessary for RNA processing.</p> Signup and view all the answers

    How does the structure of the CTD contribute to RNA processing?

    <p>It allows multiple proteins to associate simultaneously with RNA Pol II.</p> Signup and view all the answers

    Which factor is specifically recruited by phosphorylated serine 2 on the CTD?

    <p>Export factors.</p> Signup and view all the answers

    What is the role of the pCTD in relation to splicing and polyadenylation factors?

    <p>It facilitates their interaction with RNA Pol II.</p> Signup and view all the answers

    Which of the following statements correctly describes the role of specific proteins like CDK7 and CDK9?

    <p>They assist in phosphorylation of the CTD during transcription.</p> Signup and view all the answers

    What is the primary function of hnRNPs in relation to mRNA?

    <p>They regulate pre-mRNA splicing and transport mRNAs out of the nucleus.</p> Signup and view all the answers

    How do hnRNPs interact with mRNA?

    <p>Through their RNA-binding domains.</p> Signup and view all the answers

    In which cellular compartment do hnRNPs perform their functions?

    <p>In the nucleus during mRNA processing.</p> Signup and view all the answers

    Which of the following statements accurately describes hnRNPs?

    <p>They are involved in mRNA splicing from the moment of transcription.</p> Signup and view all the answers

    What occurs during the recruitment of U4, U5, and U6 snRNPs in the RNA splicing process?

    <p>They form a complex with the pre-mRNA and other snRNPs.</p> Signup and view all the answers

    Which statement accurately describes the role of U1 and U2 snRNPs in RNA splicing?

    <p>They bind to specific sites on the pre-mRNA molecule.</p> Signup and view all the answers

    What process takes place during the transesterification reactions in RNA splicing?

    <p>The pre-mRNA is cut and rejoined without using ATP.</p> Signup and view all the answers

    What is the final outcome of the RNA splicing process involving the spliceosome?

    <p>The release of mature mRNA for translation.</p> Signup and view all the answers

    Which protein complex is associated with the removal and degradation of introns in the splicing process?

    <p>U5 snRNP</p> Signup and view all the answers

    What is the main function of the 5' methylguanylate cap added to nascent mRNA?

    <p>It protects the mRNA from degradation.</p> Signup and view all the answers

    At what length of nucleotides does the addition of the 5' cap occur during mRNA synthesis?

    <p>25 nucleotides</p> Signup and view all the answers

    Which enzyme is responsible for adding the 5' cap to nascent mRNA?

    <p>Dimeric capping enzyme</p> Signup and view all the answers

    Which factor replaces NELF during the elongation phase associated with RNA Pol II?

    <p>PAF elongation complex</p> Signup and view all the answers

    What does the 5' methylguanylate cap facilitate in mRNA processing?

    <p>Nuclear export of mRNA</p> Signup and view all the answers

    What is the primary function of U1 snRNA in the spliceosome process?

    <p>It contacts the intron splice site border.</p> Signup and view all the answers

    Which of the following correctly describes the role of U2 snRNA in the splicing process?

    <p>It recognizes the branch point region.</p> Signup and view all the answers

    What occurs first during the transesterification reactions in mRNA splicing?

    <p>The OH group at the branch point attacks the 5' phosphate of the first intron residue.</p> Signup and view all the answers

    Which snRNPs are included in the active spliceosome during mRNA splicing?

    <p>U2, U5, U6</p> Signup and view all the answers

    What structural form does the intronic region take during splicing based on the transesterification reaction?

    <p>A lariat (lasso-shaped) structure.</p> Signup and view all the answers

    What is the primary role of histone proteins in DNA packaging?

    <p>To wrap around DNA, forming nucleosomes</p> Signup and view all the answers

    Which of the following correctly describes heterochromatin?

    <p>It is densely packed and transcriptionally inactive</p> Signup and view all the answers

    What is the size of the nucleosome structure formed by DNA and histone proteins?

    <p>30 nm</p> Signup and view all the answers

    Where is euchromatin primarily located, and what is its state?

    <p>Scattered throughout the nucleus and accessible to transcription</p> Signup and view all the answers

    What leads to the formation of metaphase chromosomes?

    <p>The condensation of 30 nm fiber into loops</p> Signup and view all the answers

    What is the main function of histone acetyl-transferases (HATs) in the regulation of transcription?

    <p>They transfer acetyl groups to histones, enhancing transcriptional activation.</p> Signup and view all the answers

    What role do transcriptional repressors play in histone modification?

    <p>They recruit histone deacetylase complexes (HDACs) to suppress transcription.</p> Signup and view all the answers

    How does histone acetylation affect the interaction between histones and DNA?

    <p>It neutralizes electrostatic interactions, allowing for complex formation.</p> Signup and view all the answers

    Which of the following terms describes the sequence that a transcriptional activator specifically binds to for enhancing gene expression?

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

    What defines an epigenetic trait?

    <p>A trait passed on without changing the DNA sequence.</p> Signup and view all the answers

    How do protein modifications affect gene activity in relation to histone marks?

    <p>They compact chromatin and repress gene activity over a whole region.</p> Signup and view all the answers

    What is the role of histone methyltransferase (HMT) during DNA replication?

    <p>To recognize old methylation marks and add them to new histones.</p> Signup and view all the answers

    What happens to methylated histones during DNA replication?

    <p>They are split evenly between new DNA strands.</p> Signup and view all the answers

    Which of the following best describes histone marks like H3K9 methylation?

    <p>They compact chromatin and repress gene activity over whole regions.</p> Signup and view all the answers

    What is the primary function of the MAT locus in yeast mating types?

    <p>To actively transcribe the central mating type</p> Signup and view all the answers

    What role do HML and HMR loci play in yeast mating type determination?

    <p>They are transcriptionally silent copies of mating type genes</p> Signup and view all the answers

    Which process allows the transfer of mating type information to the MAT locus from HMR or HML?

    <p>Non-reciprocal recombination</p> Signup and view all the answers

    What distinguishes the transcriptional state of the HML and HMR loci from the MAT locus?

    <p>Both HML and HMR are transcriptionally silent copies</p> Signup and view all the answers

    Which feature of yeast chromosome III is critical for mating type regulation?

    <p>The silencer regions that repress gene expression</p> Signup and view all the answers

    What is the purpose of XIST in the context of dosage compensation?

    <p>To silence one X chromosome in females</p> Signup and view all the answers

    How does TSIX function in relation to XIST during early embryonic development?

    <p>TSIX prevents XIST activation on one X chromosome</p> Signup and view all the answers

    Which of the following correctly describes the Barr Body?

    <p>The inactivated X chromosome in females</p> Signup and view all the answers

    What role does XIST play in X chromosome repression?

    <p>Functions in cis to silence the X chromosome it is transcribed from</p> Signup and view all the answers

    During which phase does TSIX cease its activity, allowing for XIST to inactivate one of the X chromosomes?

    <p>In the early stages of embryonic development</p> Signup and view all the answers

    What is the role of RAP1 in the DNA silencing mechanism?

    <p>It binds to the silencer region of DNA.</p> Signup and view all the answers

    Which proteins cooperate with each other to bind to the silencer region in DNA?

    <p>RAP1 and SIR1</p> Signup and view all the answers

    What is the function of the SIR2, SIR3, and SIR4 proteins in the silencing process?

    <p>They bind to hypoacetylated histone tails to compact chromatin.</p> Signup and view all the answers

    What triggers the process of chromatin compaction leading to transcriptional silencing?

    <p>Hypoacetylation of histone tails</p> Signup and view all the answers

    How do SIR proteins interact with telomeric DNA in the silencing mechanism?

    <p>They form large complexes that include telomeric DNA.</p> Signup and view all the answers

    What hypothesis is supported by the observation that expression of reporter increased and decreased over time?

    <p>Burst Hypothesis</p> Signup and view all the answers

    How does the frequency of transcription bursts relate to the efficiency of transcription?

    <p>It directly correlates with strength of enhancer.</p> Signup and view all the answers

    Which condition would likely result in the lowest expression of the downstream gene?

    <p>Enhancer deletion</p> Signup and view all the answers

    In the context of gene regulation, what is the significance of the enhancer's position relative to the promoter?

    <p>Both 5' and 3' placements can influence transcription levels.</p> Signup and view all the answers

    What role does the Mediator play in eukaryotic transcription?

    <p>It acts as a bridge between cis-acting elements and RNA Polymerase II.</p> Signup and view all the answers

    Which structural component of the Mediator enhances interaction with activation domains?

    <p>The subunit complex</p> Signup and view all the answers

    How does the Mediator induce the formation of the pre-initiation complex (PIC)?

    <p>By creating chromatin loops that bridge essential components.</p> Signup and view all the answers

    What is the significance of chromatin loops in the context of the Mediator complex?

    <p>They allow for the interaction of Enhancers with Transcription Factors.</p> Signup and view all the answers

    What is one function of the Mediator in regulating gene expression?

    <p>To facilitate the binding of enhancers to activators.</p> Signup and view all the answers

    What is the role of the added sequence at the 5' region of a gene during transcription?

    <p>It binds to a protein that can indicate transcription levels.</p> Signup and view all the answers

    In the context of increased transcription, what is the significance of using an in vivo technique?

    <p>It focuses solely on RNA that is actively transcribed.</p> Signup and view all the answers

    Which component is essential for linking the transcribed RNA to the reporter protein?

    <p>The sequence added to the 5' region of the gene.</p> Signup and view all the answers

    How does the binding of the reporter protein affect the study of transcription?

    <p>It provides a visual marker to identify actively transcribing genes.</p> Signup and view all the answers

    What primarily influences the formation of liquid-liquid condensates, such as P-granules?

    <p>Valency and concentration of macromolecules</p> Signup and view all the answers

    Which of the following factors is NOT typically found within a P-granule?

    <p>Vesicular transport proteins</p> Signup and view all the answers

    Which characteristic of intrinsically disordered proteins contributes to P-granule formation?

    <p>Their capacity for transient interactions</p> Signup and view all the answers

    What role do electrostatic interactions play in the formation of P-granules?

    <p>They stabilize the liquid-liquid condensate structure.</p> Signup and view all the answers

    Which statement accurately describes the content of a P-granule?

    <p>P-granules consist of a mixture of transcription factors, RNA, and proteins.</p> Signup and view all the answers

    What role do enhancers play in the Dynamic Kissing Model?

    <p>They dynamically interact with promoters to facilitate transcriptional activation.</p> Signup and view all the answers

    How do bursts in transcriptional activation correlate according to the Dynamic Kissing Model?

    <p>They may correlate with the formation and dissolution of P-granules.</p> Signup and view all the answers

    What does the arrow labeled 'Dynamic kissing model' represent in the diagram?

    <p>The active interaction between enhancers and promoters.</p> Signup and view all the answers

    What is the primary function of the Mediator Condensate in the Dynamic Kissing Model?

    <p>To act as a scaffold for enhancer-promoter interactions.</p> Signup and view all the answers

    Study Notes

    mRNA Processing

    • Modifications at the 5' and 3' ends of pre-mRNA are crucial for stability and protection.
    • Three main co-transcriptional steps in mRNA processing:
      • 5' Capping: A modification at the 5' end.
      • 3' Cleavage and Polyadenylation: A specific sequence is cleaved, and a poly(A) tail is added to the 3' end.
      • RNA Splicing: Removing introns and joining exons to create the final mRNA molecule.

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    Description

    Test your knowledge on the essential steps of mRNA processing, including modifications at the 5' and 3' ends. This quiz covers 5' capping, 3' cleavage and polyadenylation, and RNA splicing. Understand the significance of these processes in creating functional mRNA.

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