DNA Structures and Replication
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Questions and Answers

What is the approximate size range of plasmids in terms of base pairs (bp)?

  • 10^3 - 10^5 bp (correct)
  • 10^5 - 10^7 bp
  • 10^2 - 10^4 bp
  • 10^4 - 10^6 bp

    • Which type of enzyme cleaves DNA strands at specific DNA sequences?

  • Ligase
  • Endonuclease (correct)
  • Helicase
  • Polymerase

    • Which enzyme is responsible for hydrolyzing the phosphodiester bond within a polynucleotide chain?

  • Restriction enzyme
  • Polymerase
  • Endonuclease (correct)
  • Exonuclease

    • What is the approximate length of the E.coli chromosome DNA?

    <p>1.7 mm</p> Signup and view all the answers

    Why is DNA supercoiling important in bacterial cells?

    <p>To compact DNA within the small cell size</p> Signup and view all the answers

    What property makes poly-deoxyribonucleotides suitable for long-term storage of genetic information?

    <p>High stability of phosphodiester bonds</p> Signup and view all the answers

    What was the turning point in DNA development that gave rise to modern molecular biology?

    <p>Discovery of the double helix structure by Watson and Crick</p> Signup and view all the answers

    In the structure of DNA, where are the phosphate and sugar groups located?

    <p>On the outside of the helix</p> Signup and view all the answers

    What type of DNA structure twists in a clockwise direction?

    <p>Double helix</p> Signup and view all the answers

    Which model of DNA structure was proposed by Watson and Crick?

    <p>Double helix</p> Signup and view all the answers

    What is the main function of DNA polymerases?

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

    What is the purpose of telomere maintenance in DNA?

    <p>Preventing degradation of chromosomes during replication</p> Signup and view all the answers

    What are the three families of LINE elements?

    <p>LINE1, LINE2, LINE3</p> Signup and view all the answers

    Which retroelement is known for lacking autonomous transposition capability?

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

    What is the most common SINE element?

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

    Why can the insertion of LINE1, Alu, and SINE sequences into coding regions of genes lead to genetic diseases?

    <p>They cause gene inactivation</p> Signup and view all the answers

    Under what conditions has transposition of SINE and LINE elements been observed?

    <p>In vitro</p> Signup and view all the answers

    What is the status of LINE1 sequences with respect to active transposition in the human genome?

    <p>Majority are dormant or deactivated</p> Signup and view all the answers

    What types of base-to-base interactions determine the stability of the DNA double helix?

    <p>Base stacking (π stacking) and hydrophobic interactions</p> Signup and view all the answers

    What initiated a new era of biology according to Watson and Crick's 1953 paper in Nature?

    <p>The suggestion of the structure of the DNA double helix</p> Signup and view all the answers

    Where do deep major grooves occur in the DNA double helix?

    <p>Where sugar-phosphate skeletons are far apart</p> Signup and view all the answers

    What did Watson and Crick want to suggest in their 1953 paper?

    <p>The structure of the nucleic acid salt of deoxyribose (DNA)</p> Signup and view all the answers

    What kind of pairing do complementary nucleotide strands exhibit in the DNA double helix?

    <p>Antiparallel pairing</p> Signup and view all the answers

    Where do proteins that bind DNA interact specifically according to the text?

    <p>With major and minor grooves</p> Signup and view all the answers

    What is the main function of DNA helicase in the replication process?

    <p>Separating DNA strands</p> Signup and view all the answers

    Which enzyme is responsible for synthesizing a short RNA primer during replication?

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

    What is the function of single-strand binding proteins (SSB) during replication?

    <p>Bind to single-stranded fragments to prevent hairpin-like structures</p> Signup and view all the answers

    Why is DNA Polymerase unable to initiate the synthesis of a new DNA strand from scratch?

    <p>Requirement for a short RNA primer</p> Signup and view all the answers

    What are the small DNA fragments on the lagging strand called?

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

    Which enzyme initiates replication in eukaryotes by synthesizing a short primer?

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

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