Molecular Biology: DNA Replication
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Questions and Answers

What is the function of the primase complex during DNA replication?

  • To unwind the double helix
  • To join Okazaki fragments together
  • To synthesize RNA primers for both leading and lagging strands (correct)
  • To synthesize the leading strand

    • What is the main function of DNA polymerase-δ during lagging strand synthesis?

  • To synthesize the leading strand
  • To polymerize the lagging strand (correct)
  • To unwind the double helix
  • To remove RNA primers from the newly synthesized strand

    • What is the purpose of ribonucleases during DNA replication?

  • To remove RNA primers from the newly synthesized strand (correct)
  • To polymerize the lagging strand
  • To unwind the double helix
  • To synthesize the leading strand

    • What is the characteristic feature of telomeres?

    <p>They are composed of a highly repetitive sequence</p> Signup and view all the answers

    What is the function of the PCNA ring during DNA replication?

    <p>To load onto DNA as a clamp</p> Signup and view all the answers

    What is the characteristic of the G-rich strand at the telomere end?

    <p>It is single-stranded</p> Signup and view all the answers

    What is the mode of DNA replication?

    <p>Concurrent, where both strands are synthesized simultaneously</p> Signup and view all the answers

    Which of the following is NOT a function of helicase in DNA replication?

    <p>Protecting single-strand DNA from nucleases</p> Signup and view all the answers

    What is the function of RPA in DNA replication?

    <p>To protect single-strand DNA from nucleases and prevent secondary structures</p> Signup and view all the answers

    What is the main function of topoisomerase in DNA replication?

    <p>To relieve tensions created by the replication bubble</p> Signup and view all the answers

    Which DNA polymerase is involved in leading strand synthesis?

    <p>DNA polymerase ε</p> Signup and view all the answers

    What is the function of PCNA in DNA replication?

    <p>To thread onto DNA and prevent the complex from falling off</p> Signup and view all the answers

    What is the primary function of primase in DNA replication?

    <p>To form RNA primers</p> Signup and view all the answers

    What is the characteristic of lagging strand synthesis?

    <p>Discontinuous synthesis through Okazaki fragments</p> Signup and view all the answers

    What is the primary reason for the formation of loops at the telomere?

    <p>The nature of the G-tail, which can complement internal tracks of telomere sequence</p> Signup and view all the answers

    What is the main function of telomeres?

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

    What happens to telomeres during DNA replication?

    <p>They get shorter</p> Signup and view all the answers

    What is the consequence of short telomeres?

    <p>Senescence and apoptosis</p> Signup and view all the answers

    What is the role of telomere-specific proteins?

    <p>To recognize the telomere sequence and bind telomeres</p> Signup and view all the answers

    What is the effect of short telomeres on the CNS?

    <p>Increased risk of diseases such as Alzheimer's and Parkinson's</p> Signup and view all the answers

    What is the relationship between telomere shortening and disease?

    <p>Telomere shortening leads to disease development</p> Signup and view all the answers

    What is the function of the ORC and MCM proteins in DNA replication?

    <p>To recognize origins of replication and recruit the DNA replication machinery</p> Signup and view all the answers

    In what direction does DNA synthesis always proceed?

    <p>5′→3′</p> Signup and view all the answers

    What is the function of DNA primers in DNA replication?

    <p>To provide a starting point for DNA synthesis</p> Signup and view all the answers

    What is the result of DNA replication?

    <p>Two identical strands of DNA, each with one old strand and one new strand</p> Signup and view all the answers

    What is the function of helicase in DNA replication?

    <p>To unwind double-stranded DNA</p> Signup and view all the answers

    What is the function of topoisomerase in DNA replication?

    <p>To relax torsional stress in DNA</p> Signup and view all the answers

    How does DNA polymerase initiate chain synthesis?

    <p>Using a short, preexisting RNA or DNA strand as a primer</p> Signup and view all the answers

    What is the characteristic of DNA replication?

    <p>It is semi-conservative</p> Signup and view all the answers

    What is the direction of DNA replication?

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

    ThePrimase complex synthesizes short RNA _______ of approximately 10nt.

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

    The _______ strand is synthesized by a complex of DNA polymerase δ (Pol δ)-PCNA-Rfc.

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

    During concurrent DNA replication, both the _______ and leading strands are synthesized simultaneously.

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

    Ribonucleases are required to remove the RNA _______ from the newly synthesized strand.

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

    A DNA polymerase adds deoxynucleotides to the free hydroxyl group at the ______ end of the primer

    <p>3′</p> Signup and view all the answers

    Primases are required to form the ______ primers required for DNA polymerases

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

    The G-rich strand at the telomere end terminates in a single-stranded _______ of approximately 75-300 nucleotides.

    <p>G-tail</p> Signup and view all the answers

    DNA replication is described as ______-discontinuous due to the different mechanisms of leading and lagging strand synthesis

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

    Topoisomerases are required to ______ the tensions created by the replication bubble

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

    Helicases are required for the ______ of the parental DNA strands

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

    Most eukaryotic chromosomes bend back on themselves to form a physical ______ at the telomere.

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

    The main function of telomeres is ______.

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

    Telomeres are recognized by a series of proteins that can be classified as ______ proteins and telomere non-specific proteins.

    <p>telomere specific</p> Signup and view all the answers

    Short telomeres play a central role in the development of ______ diseases.

    <p>age-related</p> Signup and view all the answers

    Telomere shortening leads to ______.

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

    DNA replication is _______________, meaning that each new DNA has one ‘old’ strand and one ‘new’ strand.

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

    The pre-_____________________ complex is formed by ORC proteins and MCM proteins that recognize origins of replication.

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

    DNA polymerase requires a short, preexisting RNA or DNA strand, called a _______________, to begin chain growth.

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

    DNA replication is _______________, meaning that it starts at the origin of replication and proceeds in both directions.

    <p>bi-directional</p> Signup and view all the answers

    The enzymatic activity of DNA polymerase is essential for DNA replication, but it cannot initiate chain synthesis de novo and requires a _______________.

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

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