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What is the primary role of transcription factors in eukaryotic transcription?

  • To form a pre-initiation complex with RNA polymerase II (correct)
  • To regulate the transition from DNA replication to transcription
  • To synthesize RNA molecules directly
  • To provide energy for the transcription process

    • Which of the following statements correctly describes RNA polymerase II in eukaryotes?

  • It is responsible for synthesizing all types of RNA.
  • It is part of a multi-subunit complex needed for transcription initiation. (correct)
  • It synthesizes RNA in the 3’-to-5’ direction.
  • It directly binds to the core promoter without assistance.

    • What unique components does TFIID consist of?

  • General transcription factors and splicing factors
  • TATA-binding protein (TBP) and TBP-Associated Factors (TAFs) (correct)
  • RNA polymerase II and transcription factors A and B
  • Initiator proteins and elongation factors

    • What is the primary function of the promoter region in eukaryote transcription?

    <p>To serve as the binding site for RNA polymerase</p> Signup and view all the answers

    Which element is specifically associated with the formation of the preinitiation complex during transcription initiation?

    <p>TATA box</p> Signup and view all the answers

    In which direction is RNA synthesized during transcription?

    <p>5'-to-3'</p> Signup and view all the answers

    How many base pairs is the core promoter typically located from the transcription start site (TSS)?

    <p>About -40 to +40 base pairs</p> Signup and view all the answers

    What defines the template strand of DNA during RNA synthesis?

    <p>The DNA strand that is complementary to RNA</p> Signup and view all the answers

    What is the consensus sequence for the initiator element (INR) in mammalian RNA polymerase II transcription?

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

    Which transcription factor primarily recognizes the B recognition element (BRE)?

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

    What is the main purpose of the 5' cap added to mRNA during processing?

    <p>It aids in the transport of mRNA out of the nucleus.</p> Signup and view all the answers

    How does the poly(A) tail contribute to mRNA stability?

    <p>By protecting mRNA from exonuclease degradation.</p> Signup and view all the answers

    Which enzyme is responsible for adding the 5' cap to a newly synthesized mRNA molecule?

    <p>Capping enzymes</p> Signup and view all the answers

    What sequence does the endonuclease cleave to initiate the addition of the poly(A) tail?

    <p>AUAAA sequence</p> Signup and view all the answers

    Which of the following components is involved in the recruitment of enzymes for the poly(A) tail addition?

    <p>Phosphorylated CTD</p> Signup and view all the answers

    What are introns primarily characterized by in the context of RNA processing?

    <p>They are noncoding sequences that are removed from pre-RNA.</p> Signup and view all the answers

    Which splice site is associated with intron removal during mRNA processing?

    <p>3’ splice site - AG/G</p> Signup and view all the answers

    What is the function of exonic splicing enhancers (ESE)?

    <p>They help recruit small nuclear ribonuclear proteins (snRNPs).</p> Signup and view all the answers

    Which of the following statements is true regarding small nuclear ribonuclear proteins (snRNPs)?

    <p>They contain small nuclear RNAs (snRNAs) and associated proteins.</p> Signup and view all the answers

    Approximately what percentage of inherited diseases in humans is estimated to arise from errors in RNA splicing?

    <p>15-30%</p> Signup and view all the answers

    What primarily determines the expression of myofibers versus skin fibroblasts?

    <p>The transcriptional state governed by genes</p> Signup and view all the answers

    What is the role of activator transcription factors?

    <p>To stimulate transcription of specific genes</p> Signup and view all the answers

    Which domain of transcription factors promotes interaction with other proteins?

    <p>Activation domain</p> Signup and view all the answers

    What effect do zinc finger motifs primarily have in transcription factors?

    <p>They bind to major grooves in target DNA</p> Signup and view all the answers

    How are transcription factors typically characterized in terms of their regulation of genes?

    <p>Every gene is regulated by multiple transcription factors</p> Signup and view all the answers

    What structure in the nucleus is responsible for providing mechanical support and anchoring chromatin?

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

    Which of the following correctly describes a polysome?

    <p>Multiple ribosomes bound to a single mRNA</p> Signup and view all the answers

    The primary transcript (mRNA precursor) includes which of the following?

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

    What is the primary function of the nuclear pores in the nuclear envelope?

    <p>Facilitate RNA transport out of the nucleus</p> Signup and view all the answers

    What machinery is responsible for the removal of introns during RNA processing?

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

    What disease is characterized by its impact on the muscular system and is mentioned in the list?

    <p>Duchenne Muscular Dystrophy</p> Signup and view all the answers

    Which of the following conditions is classified under neurological diseases in the list provided?

    <p>Tourette Syndrome</p> Signup and view all the answers

    What type of replication occurs in both prokaryotes and eukaryotes?

    <p>Semi-conservative replication</p> Signup and view all the answers

    During which phase of the cell cycle does DNA replication occur in eukaryotic cells?

    <p>S phase</p> Signup and view all the answers

    How many replicons are typically engaged in DNA replication during the S phase in human cells?

    <p>10,000-100,000</p> Signup and view all the answers

    What is the function of the replication fork during DNA replication?

    <p>It is the site where nucleotides are incorporated</p> Signup and view all the answers

    What is the role of the DNA polymerase holoenzyme in DNA replication?

    <p>It synthesizes the daughter strands of DNA</p> Signup and view all the answers

    Which statement accurately describes the function of DNA polymerase III in prokaryotes?

    <p>It extends RNA primers with new DNA nucleotides.</p> Signup and view all the answers

    What is the role of single-stranded DNA-binding (SSB) proteins during DNA replication?

    <p>They stabilize the unwound DNA strands to prevent re-annealing.</p> Signup and view all the answers

    Which of the following events occurs during the initiation of DNA replication in eukaryotic cells?

    <p>Pre-replication complexes are activated by protein kinases.</p> Signup and view all the answers

    What characterizes the lagging strand during DNA replication?

    <p>It is synthesized discontinuously with Okazaki fragments.</p> Signup and view all the answers

    Which enzyme is responsible for relieving the tension caused by supercoiling during DNA unwinding in eukaryotes?

    <p>Type I topoisomerases</p> Signup and view all the answers

    What type of mutation results in a premature stop codon?

    <p>Nonsense mutation</p> Signup and view all the answers

    Which category of genetic mutation may lead to frameshifts?

    <p>Insertions and deletions</p> Signup and view all the answers

    How does a conservative missense mutation differ from other missense mutations?

    <p>It changes the amino acid to one with similar properties.</p> Signup and view all the answers

    Which of the following is an example of a genetic condition caused by a nonsense mutation?

    <p>Cystic Fibrosis</p> Signup and view all the answers

    What characterizes a point mutation?

    <p>It is a permanent change in the DNA sequence.</p> Signup and view all the answers

    What describes a missense mutation?

    <p>A mutation that causes a different amino acid to be produced</p> Signup and view all the answers

    What is the main consequence of a trinucleotide repeat expansion?

    <p>Formation of toxic protein aggregates</p> Signup and view all the answers

    What genetic error is primarily responsible for Down Syndrome?

    <p>Nondisjunction of chromosome 21</p> Signup and view all the answers

    Which type of mutation involves a change in the number or structure of chromosomes?

    <p>Copy number variations</p> Signup and view all the answers

    What is a characteristic feature of the MYC gene in relation to cancer?

    <p>It is commonly duplicated in various cancers</p> Signup and view all the answers

    What is the primary function of G protein-coupled receptors (GPCRs)?

    <p>To activate signaling pathways through ligand binding</p> Signup and view all the answers

    What happens to the G protein when GDP is exchanged for GTP?

    <p>The G protein activates the effector protein</p> Signup and view all the answers

    Which process is initiated after ligand binding to a GPCR?

    <p>Dissociation of G protein subunits</p> Signup and view all the answers

    Which of the following molecules can serve as ligands for GPCRs?

    <p>Peptides and proteins</p> Signup and view all the answers

    What is the ultimate effect of activated Gα subunit on adenylyl cyclase?

    <p>It activates adenylyl cyclase to increase ATP conversion to cAMP</p> Signup and view all the answers

    What occurs to the Gα subunit after GTP is hydrolyzed?

    <p>It becomes inactive and associates with Gβγ.</p> Signup and view all the answers

    Which enzyme is primarily activated by the GTP-bound Gα subunit?

    <p>Adenylyl cyclase</p> Signup and view all the answers

    What process is inhibited by the binding of arrestin protein to the receptor?

    <p>G protein activation by the receptor.</p> Signup and view all the answers

    What happens when a ligand binds to the GPCR?

    <p>It alters receptor conformation.</p> Signup and view all the answers

    Which of the following is a consequence of G protein activation?

    <p>GDP is exchanged for GTP.</p> Signup and view all the answers

    What is the primary role of second messengers in cell signaling?

    <p>Activate or inactivate target proteins</p> Signup and view all the answers

    Which G protein is associated with the production of IP3 and DAG?

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

    What does CREB primarily bind to in the context of cAMP signaling?

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

    Which G protein signaling pathway leads to a decrease in cAMP levels?

    <p>Gi signaling pathway</p> Signup and view all the answers

    What cellular response is associated with the activation of Protein Kinase A (PKA)?

    <p>Increased transcription of cAMP-sensitive genes</p> Signup and view all the answers

    What happens to cGMP levels in rod cells when exposed to light?

    <p>cGMP levels decrease</p> Signup and view all the answers

    Which G protein is involved in the signaling pathway related to light perception in rod cells?

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

    What is the primary role of phospholipase C (PLC) in cell signaling?

    <p>To cleave PIP2 into IP3 and DAG</p> Signup and view all the answers

    What is the effect of mutations in the RGS9 gene on visual processing?

    <p>Slower increase of cGMP leading to slower channel opening</p> Signup and view all the answers

    Which of the following statements accurately describes the role of G12/13 proteins in cell signaling?

    <p>They stimulate excessive cell proliferation</p> Signup and view all the answers

    What role does the alpha subunit of G-proteins play in G-coupled pathways?

    <p>It triggers the activation of adenylyl cyclase or phospholipase C-beta.</p> Signup and view all the answers

    Which of the following receptor types is NOT part of cellular signaling mechanisms within the outlined content?

    <p>Receptor nuclear factors</p> Signup and view all the answers

    What is the outcome of the activation of protein kinase A (PKA) in G-coupled pathways?

    <p>Regulation of gene transcription by phosphorylating transcription factors.</p> Signup and view all the answers

    What event occurs when a ligand binds to a G-protein coupled receptor (GPCR)?

    <p>Conformational change that activates G-proteins.</p> Signup and view all the answers

    What molecule is produced from ATP in the cAMP signaling pathway?

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

    What process allows receptor tyrosine kinases (RTKs) to terminate their signaling response?

    <p>Receptor-mediated endocytosis</p> Signup and view all the answers

    Which of the following relay proteins acts as a docking station for signaling proteins?

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

    What happens during trans-autophosphorylation in receptor tyrosine kinases?

    <p>The receptor phosphorylates itself</p> Signup and view all the answers

    Which role does CBL (Casitas B-lineage Lymphoma) protein play in the signaling of receptor tyrosine kinases?

    <p>Ubiquitinates RTK for internalization</p> Signup and view all the answers

    Which type of protein functions as a linker in a signaling complex during RTK signaling?

    <p>Adaptor proteins</p> Signup and view all the answers

    Study Notes

    Molecular Mechanisms of Disease

    • HSS2305: Course covering the molecular mechanisms behind diseases.
    • Lectures 7 and 8: Focus on interactions between cells and environment, gene transcription, and translation.
    • Cellular Components: Diagram depicts various cell structures (e.g., nucleus, cytoskeleton, endoplasmic reticulum, ribosomes, mitochondria, Golgi complex).

    Eukaryote Gene Transcription and Translation

    • Overview: Process of turning genetic information into proteins.
    • Central Dogma: DNA → RNA → Protein
    • Transcription: DNA sequence copied into mRNA.
    • Translation: mRNA decoded to build protein.

    From Genes to Proteins (Central Dogma)

    • Illustrates the process of DNA transcription and translation.
    • Shows the conversion of DNA to RNA to Protein.

    From Genes to Proteins (Complex)

    • Details gene to protein mechanisms, encompassing transcription and translation
    • Highlights the intricate steps in transferring information from DNA to Protein.
    • Illustrates pre-mRNA processing steps: addition of 5' cap and 3' Poly-A tail
    • Illustrates the role of mRNA, tRNA, and rRNA in protein synthesis

    From Genes to Proteins (Video)

    • Discusses protein synthesis, covering DNA transcription, translation, and folding.

    Transcription

    • Synthesis of RNA from DNA in nucleus.
      • Starting Material: DNA
      • Required machinery: RNA polymerase II, transcription factors
      • End product: Messenger RNA (mRNA) after processing.

    Translation

    • Synthesis of proteins from mRNA in cytoplasm.
      • Starting Material: mRNA
      • Required machinery: Ribosomal RNA (rRNA) and ribosomal proteins, transfer RNA (tRNA)
      • End product: Polypeptide (protein).

    Sense vs Antisense DNA Strands

    • Coding strand is identical to mRNA except uracil replaces thymine.
    • Template or antisense strand serves as the DNA template.

    Transcription (Gene Structure)

    • Both DNA strands code for genes, illustrated in diagram.
    • DNA size: 3.6 x 104 bp (base pairs)
    • Replication and Transcription illustrated at gene level.

    Transcription (RNA Polymerase)

    • RNA polymerase binds to DNA.
      • Specific site: Promoter region
    • Incorporates nucleotide into RNA strand.
    • Prokaryotes: Single RNA polymerase to transcribe all RNA.
    • Eukaryotes: Three different RNA polymerases (I, II, III).

    Eukaryote Transcription (RNA Polymerase)

    • DNA-dependent RNA polymerase
    • RNA synthesis in 5' to 3' direction.
    • Template strand(3'to 5'): Read to make RNA strand

    Eukaryote Transcription (Core Promoter)

    • Site of RNA polymerase binding before transcription.
      • Determines strand used as template (anti-sense strand).
      • Has precise sequences.
      • Core and proximal elements within 250 base pairs of start site.

    Eukaryote Transcription (Core Promoter)

    • Key elements: TATA box, initiator sequences, other motifs.
    • Required for general TF's binding and RNA Pol II binding.
    • TATA box, BRE, Inr, DPE sequences.

    Eukaryote Transcription (Core Promoter Elements)

    • Initiator element (INR), flanking the start site.
    • Downstream promoter element (DPE).
      • Located downstream of transcription start site
    • Various factors binding to the core promoter.

    Eukaryote Transcription (Proximal Promoter Elements)

    • Contains binding sites for specific transcription factors.
    • Influences gene expression timing and level.
    • Important elements like CAAT box and GC box.

    Eukaryote Transcription (Enhancer Regions)

    • Far from start, regulates transcription.
    • Can be thousands of base pairs away from target gene.
    • Interact with the pre-initiation complex.

    Eukaryote Transcription (Pre-Initiation Complex (PIC))

    • Proteins assemble to initiate transcription of protein-coding genes.
    • Positions RNA polymerase II for initiation site.
    • Requires many protein components.

    Eukaryote Transcription (Pre-Initiation Complex (PIC) Formation)

    • TFIID (TBP+TAFs), binds to the TATA box.
    • TFIIA, TFIIB bind to the complex, stabilizing the complex.

    Eukaryote Transcription (Elongation)

    • RNA polymerase moves along DNA, creating RNA transcript.
    • Important for maintaining correct sequence.
    • Process aided by several elongation factors.

    Eukaryote Transcription (Termination)

    • Ends transcription process.
    • Involved in RNA processing steps to determine the final mRNA length.
    • Has no well-defined sequence like in prokaryotes.

    Biological Molecules (Proteins)

    • R groups are weakly acidic or basic.
    • Cannot form full H bonds at pH7.
    • Can form H bonds with other molecules with partial charges like H2O.

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    Description

    Explore the intricate molecular mechanisms behind diseases in this quiz based on HSS2305. Focus areas include cell-environment interactions, and the processes of gene transcription and translation. Test your knowledge of cellular components and the central dogma of molecular biology.

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