RNA Transcription and Initiation
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Questions and Answers

What occurs when DNA opens and cannot rotate?

  • It remains in a relaxed state
  • It leads to downregulation
  • Supercoiling is produced (correct)
  • Transcription is halted

    • Dysregulation in gene expression can lead to disease.

    True

    Name one factor that can lead to the upregulation of genes.

    Amplification

    A transcription factor that helps activate gene expression is called a __________.

    <p>Transcriptional Activator</p> Signup and view all the answers

    What happens to the downstream DNA when a DNA region opens?

    <p>It must also rotate</p> Signup and view all the answers

    Match the following terms with their corresponding definitions:

    <p>DNA supercoiling = Conformation of DNA under superhelical tension Transcriptional Activator = Protein that promotes gene expression Gene translocations = Moving a gene from one location to another Chromatin architecture shifts = Changes in the structure of chromatin that affect gene accessibility</p> Signup and view all the answers

    A gain of function mutation typically leads to downregulation of gene expression.

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

    What is one way transcriptional activators can be regulated?

    <p>Through chromatin remodeling</p> Signup and view all the answers

    What is one function of introns in gene regulation?

    <p>They contain cis-regulatory elements.</p> Signup and view all the answers

    Introns are only found in prokaryotic genes.

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

    What is the primary advantage of alternative splicing?

    <p>It allows a single gene to produce multiple protein isoforms.</p> Signup and view all the answers

    Introns can act as a _______ to protect critical exons from harmful mutations.

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

    Which of the following is a type of non-coding RNA encoded by introns?

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

    Introns facilitate the evolution of new genes through exon shuffling.

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

    Name one way introns can influence transcription efficiency.

    <p>By affecting chromatin structure.</p> Signup and view all the answers

    The myosin heavy chain gene is an example of tissue-specific expression influenced by _______ in introns.

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

    Match the following functions with their corresponding descriptions:

    <p>Facilitation of alternative splicing = Production of multiple isoforms from a single gene Protection of coding sequences = Buffering critical exons from mutations Regulation of gene expression = Influencing transcription efficiency Evolutionary advantages = Accumulation of mutations in a safe space</p> Signup and view all the answers

    Which of the following roles do introns play in the accumulation of mutations?

    <p>They provide a safe space for mutations.</p> Signup and view all the answers

    What is the primary function of TFIIB?

    <p>Recognizes the BRE element in promoters</p> Signup and view all the answers

    TFIID consists of the TBP subunit and approximately 11 TBP-associated factors.

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

    Name the transcription factor that unwinds DNA at the transcription start point.

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

    The __________ are regions of DNA bound by up-regulatory transcription factors that enhance gene expression.

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

    Match the transcription factors with their primary functions:

    <p>TFIID = Recognizes TATA box TFIIF = Stabilizes RNA polymerase interaction TFIIE = Attracts and regulates TFIIH TFIIH = Unwinds DNA and phosphorylates RNA polymerase</p> Signup and view all the answers

    What do transcriptional activators typically contain to perform their functions?

    <p>Multiple protein domains</p> Signup and view all the answers

    Silencers are regions of DNA bound by up-regulatory transcription factors.

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

    What is the role of the TAF subunits in TFIID?

    <p>They recognize other DNA sequences near the transcription start point.</p> Signup and view all the answers

    The __________ domain of transcriptional activators allows them to bind specifically to palindromic DNA sequences.

    <p>DNA-binding</p> Signup and view all the answers

    Match the transcription factors with the components they help attract:

    <p>TFIIF = TFIIE and TFIIH TFIIE = RNA polymerase TFIIH = DNA helicase TFIID = Transcription co-factors</p> Signup and view all the answers

    Which of the following statements about introns is true?

    <p>Introns can help establish topologically associated domains (TADs).</p> Signup and view all the answers

    Alternative splicing can lead to proteins with different functional domains.

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

    Name one protein that interacts with intronic sequences.

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

    ______ is the most common form of alternative splicing.

    <p>Exon skipping</p> Signup and view all the answers

    Match the alternative splicing types with their definitions:

    <p>Exon skipping = An exon is removed from the transcript Mutually exclusive exons = Two or more exons are arranged such that only one is included Intron retention = An intron is retained in the mature mRNA Alternative 5' splice site = Selection between two or more possible 5' splice sites</p> Signup and view all the answers

    What is a consequence of retaining introns in mRNA?

    <p>Proteins may include stop codons.</p> Signup and view all the answers

    The 5' cap is added to the 3' end of the mRNA.

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

    What role do architectural proteins play in relation to introns?

    <p>They help establish chromatin looping and organization.</p> Signup and view all the answers

    In _______ splicing, the splicing machinery selects between two or more possible 3' splice sites.

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

    Which statement about the function of exons is correct?

    <p>Exons code for proteins.</p> Signup and view all the answers

    Which group is associated with a conserved secondary structure with six domains?

    <p>Group 2</p> Signup and view all the answers

    The 3'-OH group of the guanosine attacks the 3' splice site during the first transesterification.

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

    What is formed during the first transesterification of Group 2 splicing?

    <p>a lariat structure</p> Signup and view all the answers

    The intron is released and the two exons are joined during the second transesterification by the 3'-OH of the _______.

    <p>upstream exon</p> Signup and view all the answers

    Match the following components with their roles in the splicing mechanism:

    <p>Guanosine = Acts as a cofactor Adenosine residue = Initiates the first transesterification Intron = Looped structure in the splicing process Exons = Joined during second transesterification</p> Signup and view all the answers

    Which of the following is NOT a free guanine nucleotide or nucleoside that acts as a cofactor?

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

    Splicing only occurs in mitochondrial genes.

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

    Study Notes

    RNA Transcription

    • RNA polymerase is conserved across all life forms
    • Not all genes are expressed in every cell, expression varies temporally and spatially
    • ~20-40% of the genome consists of regulatory sequences
    • Misregulation of gene expression is linked to various diseases, including cancer
    • RNA polymerase unwinds DNA strands to form a transient bubble, this is done without a helicase
    • The bubble size is 12-14 bp, and the RNA/DNA hybrid region is 8-9 bp
    • RNA polymerase reads the 3'-5' template strand to synthesize 5'-3' RNA
    • Non-coding DNA sequences are frequently transcribed, producing functional RNA molecules like microRNA, lincRNA, rRNA, and tRNA

    Transcription Initiation

    • RNA polymerase II needs many proteins and cis-regulatory DNA elements
    • Different RNA polymerases have specific functions
      • RNA polymerase I transcribes rRNA genes (5.8S, 18S, and 28S rRNA)
      • RNA polymerase II transcribes mRNA, snoRNA, miRNA, siRNA, and most snRNA
      • RNA polymerase III produces tRNA genes, 5S rRNA, and some snRNA
    • Active site of RNA polymerase II is at the interface between two of its largest subunits

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    Description

    This quiz covers key concepts of RNA transcription, including the roles of RNA polymerase in gene expression and the importance of regulatory sequences. You will explore how different types of RNA are synthesized and the implications of misregulation in diseases such as cancer.

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