Molecular Biology Quiz on DNA and RNA
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Questions and Answers

What is a primary distinguishing feature of RNA polymerase compared to DNA polymerase?

  • It only functions in the presence of free nucleotides.
  • It requires a primer to start synthesizing nucleotides.
  • It can initiate a new nucleotide chain without an existing end. (correct)
  • It synthesizes DNA rather than RNA.

    • Which DNA polymerase is primarily responsible for elongating the DNA strand during replication?

  • DNA polymerase V
  • DNA polymerase I
  • DNA polymerase III (correct)
  • DNA polymerase II

    • In which direction must DNA synthesis proceed?

  • 3’ to 5’ direction
  • 5’ to 3’ direction (correct)
  • 3’ to 3’ direction
  • 5’ to 5’ direction

    • What role does DNA polymerase I (DNAP I) play during DNA replication?

    <p>It replaces the RNA primer with DNA.</p> Signup and view all the answers

    What happens to the last two phosphate groups during the addition of a nucleotide by DNA polymerase?

    <p>They are hydrolyzed to form monophosphate.</p> Signup and view all the answers

    What conclusion did Avery, McCarty, and MacLeod reach regarding the transformation of bacteria?

    <p>Only DNA from the S strain caused transformation.</p> Signup and view all the answers

    Which radioactive materials were used by Hershey and Chase to identify genetic material in viruses?

    <p>Radioactive phosphorus and sulfur.</p> Signup and view all the answers

    What was demonstrated by centrifuging the mixtures in the Hershey-Chase experiment?

    <p>Radioactive DNA was present in the bacterial pellet.</p> Signup and view all the answers

    What was the primary question driving the Hershey-Chase experiment?

    <p>Which viral component reprograms the host cell?</p> Signup and view all the answers

    What method was used to determine if DNA was the heritable material?

    <p>Analyzing the composition of the supernatant after centrifugation.</p> Signup and view all the answers

    What is the primary function of telomeres?

    <p>To protect chromosomes from erosion</p> Signup and view all the answers

    What enzyme is responsible for adding telomeres to chromosomes?

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

    How do prokaryotes avoid the problem of DNA shortening during replication?

    <p>By employing circular DNA</p> Signup and view all the answers

    In which types of cells is telomerase activity typically found?

    <p>Germ line cells</p> Signup and view all the answers

    What sequence is commonly repeated in human telomeres?

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

    At what approximate length do human telomeres generally lead to death from old age?

    <p>5,000 bases</p> Signup and view all the answers

    What is the role of telomerase in germ line cells?

    <p>Adding telomeres to chromosomes</p> Signup and view all the answers

    What happens to telomere length in humans from conception to adulthood?

    <p>Decreases progressively</p> Signup and view all the answers

    What happens to somatic cells that lack telomerase?

    <p>They age and have a finite lifespan</p> Signup and view all the answers

    Which of the following describes the process of reverse transcription in telomerase?

    <p>Synthesis of DNA using RNA as a template</p> Signup and view all the answers

    What effect does aging have on the rate of telomere shortening?

    <p>The rate initially decreases then may increase in advanced age</p> Signup and view all the answers

    What is the significance of the RNA component in human telomerase?

    <p>It acts as a template for DNA synthesis</p> Signup and view all the answers

    What is the telomere length at birth in humans?

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

    What is a characteristic of telomeres in eukaryotic chromosomes?

    <p>They consist of noncoding DNA</p> Signup and view all the answers

    What sequence does telomerase use to synthesize a complementary DNA strand?

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

    What may explain the finite lifespan of most cells?

    <p>Loss of telomeres in cell division</p> Signup and view all the answers

    What role does telomerase play in germ line cells?

    <p>It prevents the shortening of telomeres during DNA replication.</p> Signup and view all the answers

    Why might Dolly the sheep not have lived as long as typical newborns?

    <p>Dolly's telomeres were the same length as the adult sheep from which she was cloned.</p> Signup and view all the answers

    What is a characteristic of cancer cells that requires them to have telomerase activity?

    <p>They replicate infinitely without undergoing senescence.</p> Signup and view all the answers

    What is one reason why telomerase is not present in most somatic cells?

    <p>It is unnecessary for the normal functioning of these cells.</p> Signup and view all the answers

    Which enzyme is primarily responsible for DNA replication in the cells mentioned?

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

    What did Friedrich Miescher discover in 1869?

    <p>A substance he called nuclein, which is now known to be DNA.</p> Signup and view all the answers

    Why was there a debate over whether DNA or protein was the most important hereditary molecule in the early 20th century?

    <p>Proteins were known to have clear functions and vast combinations.</p> Signup and view all the answers

    What is the primary function of telomerase in relation to DNA strands?

    <p>To add nucleotide sequences to the ends of chromosomes.</p> Signup and view all the answers

    What does Phoebus Levene's Tetranucleotide hypothesis suggest about the sequence of bases in DNA?

    <p>All bases are present in equal ratios.</p> Signup and view all the answers

    What was one of the key findings by Erwin Chargaff regarding base ratios in DNA?

    <p>A = T and C = G.</p> Signup and view all the answers

    Which structural model was proposed by Linus Pauling regarding DNA?

    <p>Triple helix structure with three intertwined strands.</p> Signup and view all the answers

    What technique did Rosalind Franklin & Maurice Wilkins use to determine the structure of DNA?

    <p>X-ray diffraction.</p> Signup and view all the answers

    What error was identified in Linus Pauling's model of DNA?

    <p>Phosphates were shown as negatively charged.</p> Signup and view all the answers

    How does X-ray crystallography help in determining the structure of molecules?

    <p>By analyzing the diffraction pattern of bombarded X-rays.</p> Signup and view all the answers

    Who correctly determined that DNA is made up of chains of nucleotides?

    <p>Phoebus Levene.</p> Signup and view all the answers

    What distinct feature was highlighted in Chargaff's observations of DNA?

    <p>There is a specific ratio between purines and pyrimidines.</p> Signup and view all the answers

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