Direct Reversal vs Replacement DNA Repair Mechanisms
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Questions and Answers

What is the main result of DNA mutation?

  • Inhibition of DNA replication
  • Change in the tRNA structure
  • Increase in protein synthesis
  • Change in the mRNA codon nucleotide sequence (correct)
  • Which type of mutation arises when a base pair with an inappropriate partner during DNA replication?

  • Frameshift Mutation
  • Point Mutation (correct)
  • Nonsense Mutation
  • Silent Mutation
  • What is the result of a nonsense mutation?

  • Increase in protein synthesis
  • Creation of new proteins
  • Change in the RNA nucleotide sequence
  • Change in the protein being translated into (correct)
  • In a transition type of point mutation, what occurs?

    <p>One base pair is changed to its kind</p> Signup and view all the answers

    What is the clinical significance of a nonsense mutation?

    <p>Factor XI deficiency: a blood clotting disorder</p> Signup and view all the answers

    What does a missense mutation change?

    <p>The protein being translated into</p> Signup and view all the answers

    What are the two general classes of DNA repair discussed in the text?

    <p>Direct Reversal and Replacement of damaged bases</p> Signup and view all the answers

    Which type of DNA damage can be repaired by photoreactivation?

    <p>Formation of pyrimidine dimers</p> Signup and view all the answers

    What is the name of the enzyme involved in photoreactivation?

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

    Which DNA repair mechanism requires light for its function?

    <p>Direct reversal through photoreactivation</p> Signup and view all the answers

    What is the function of the protein MGMT in DNA repair?

    <p>Helps restore original guanine structure</p> Signup and view all the answers

    Which type of DNA damage can be reversed by O6methylguanine methyltransferase?

    <p>Methylation of guanine</p> Signup and view all the answers

    What is the consequence of a point mutation in the B-globin chain of Hemoglobin causing codon GAG to change into GUG?

    <p>Change in the amino acid coded from Glutamic Acid to Valine</p> Signup and view all the answers

    Which type of mutation refers to the loss of a single base either spontaneously or due to damage?

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

    When can frameshift mutations likely occur?

    <p>When any number of bases are added or deleted, except for multiples of three</p> Signup and view all the answers

    What causes DNA damage leading to mutation and genomic instability?

    <p>Incorrect nucleotide bases during DNA replication</p> Signup and view all the answers

    Which process can identify the correct damage in DNA molecules for repair?

    <p>DNA repair</p> Signup and view all the answers

    What does DNA encode, making it a permanent copy necessary for cell functioning?

    <p>Cell genome</p> Signup and view all the answers

    What is the term used to describe an enzyme that becomes inactivated after accepting an alkyl group through its sulfur atom of a cysteine residue?

    <p>Suicide enzyme</p> Signup and view all the answers

    Which type of repair involves the removal of a single damaged base and requires glycosylases enzymes?

    <p>Base Excision Repair</p> Signup and view all the answers

    What is the general mechanism by which repairs are made when one of the double helix strands is damaged?

    <p>Excision Repair</p> Signup and view all the answers

    What occurs after the damaged DNA on one strand is removed in the excision repair process?

    <p>The intact DNA strand is replaced by DNA polymerase</p> Signup and view all the answers

    Which repair mechanism involves recognizing damage and cleaving it on both sides by endonucleases before resynthesis by DNA polymerase?

    <p>Nucleotide Excision Repair</p> Signup and view all the answers

    What kind of damage does Nucleotide Excision Repair specifically recognize for repairs?

    <p>Formation of pyrimidine dimers from UV light</p> Signup and view all the answers

    What is the main function of mismatch repair in DNA replication?

    <p>Remove mismatched bases missed by proofreading DNA polymerase</p> Signup and view all the answers

    Which repair mechanism is particularly important in maintaining genomic integrity by fixing damage to both DNA strands?

    <p>Homologous recombination</p> Signup and view all the answers

    What is one of the risks associated with single-stranded annealing and alternative joining as repair mechanisms?

    <p>Leading to a loss in genetic information</p> Signup and view all the answers

    Which repair mechanism connects double strand break ends without using a homologous template?

    <p>Nonhomologous end joining</p> Signup and view all the answers

    What is the undefined mechanism used in repairing double strand breaks that risks genomic integrity?

    <p>Alternative joining</p> Signup and view all the answers

    How does homologous recombination repair damaged bases on both strands of DNA?

    <p>By exchanging nucleotide sequences with a sister chromatid</p> Signup and view all the answers

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