Chapter 11: DNA Replication and Recombination

  1. In the Meselson-Stahl experiment, which mode of replication was eliminated based on data derived after one generation of replication?
    1. Dispersive
    2. Semiconservative
    3. Conservative
    4. Liberal
    5. Libertarian
  2. Which DNA polymerase is mainly responsible for genome replication in E. coli?
    1. DNA polymerase III
    2. DNA polymerase alpha
    3. DNA polymerase beta
    4. DNA polymerase I
    5. DNA polymerase II
  3. Which of the following molecules is not required for the synthesis of DNA in vitro by DNA polymerase?
    1. ATP
    2. Template
    3. Deoxynucleoside triphosphates
    4. Primer
  4. Which enzyme in E. coli is responsible for relieving the tension ahead of the fork that results when the DNA is unwound to form the replication bubble or eye?
    1. Ligase
    2. Replicase
    3. Helicase
    4. DNase
    5. Gyrase
  5. Why is an RNA primer considered essential for DNA synthesis by DNA polymerase III?
    1. There is no particular reason; that is simply what has been observed.
    2. The enzyme requires a free 3'-OH group.
    3. The enzyme requires a free 5'-OH group.
    4. The enzyme requires a free 3'-PO4 group.
    5. The enzyme requires a free 5'-PO4 group.

  6. Which of the following statements best describes Okazaki fragments?
    1. They are formed in the leading strand.
    2. They add nucleotides to the elongating DNA.
    3. They are formed in the lagging strand.
    4. They are synthesized by primase.
    5. They are synthesized by ligase.
  7. Which enzyme or enzymatic activity is not involved in resolution of the Okazaki fragments in E. coli?
    1. DNA ligase
    2. 5' to 3' exonuclease activity of DNA polymerase I
    3. RNA ligase
    4. 5' to 3' polymerase activity of DNA polymerase I
  8. Which activity of E. coli DNA polymerase I is responsible for proofreading the newly synthesized DNA?
    1. 5' to 3' polymerase
    2. 3' to 5' endonuclease
    3. 3' to 5' exonuclease
    4. 5' to 3' exonuclease
    5. 5' to 3' endnuclease
  9. All of the following are differences between eukaryotic and prokaryotic DNA replication except
    1. The type and number of polymerases involved in DNA synthesis
    2. The number of replication origins
    3. The rate of DNA synthesis
    4. The ability to form a replication fork
  10. Which of the following characteristics cannot be attributed to telomeres?
    1. Telomerase enzyme
    2. Formation of hairpin loops
    3. Links to the aging process
    4. Found in eukaryotes and prokaryotes

  11. Which term describes a genetic exchange between two DNA molecules with substantial DNA sequence homology?
    1. Homologous recombination
    2. Somatic recombination
    3. Illegitimate recombination
    4. Site-specific recombination
    5. Homogeneous recombination
  12. Which event is the consequence of a mismatch in the heteroduplex that forms during general recombination?
    1. Strand invasion
    2. Holliday structure formation
    3. Gene conversion
    4. Branch migration
    5. Genetic shift
  13. Which of the following statements about DNA replication is true?
    1. DNA synthesis is continuous on the leading strand and discontinuous on the lagging strand.
    2. DNA synthesis is discontinuous on the leading strand.
    3. DNA synthesis is conservative on the leading strand and semiconservative on the lagging strand.
    4. The two replication forks move in the same direction.
  14. The discovery of Okazaki fragments suggested that DNA synthesis is
    1. Dispersive
    2. Discontinuous
    3. Continuous
    4. Semiconservative
    5. Reversible
  15. Which one of the following proteins and enzymes do not function at the origin of replication in E. coli?
    1. DNA ligase
    2. SSBPs
    3. Helicase
    4. DnaA, DnaB and DnaC proteins

  16. Which enzyme is responsible for the removal of the RNA primers at the origin and at the 5' ends of the Okazaki fragments in E. coli?
    1. DNA ligase
    2. Primase
    3. DNA polymerase I
    4. DNA polymerase II
    5. DNA polymerase III
  17. The overall rate of eukaryotic replication is essentially the same as it is in prokaryotes, even though eukaryotic genomes are hundreds to thousands of times bigger than their prokaryotic counterparts. Which of the following statements could account for this observation?
    1. The DNA polymerases in eukaryotes are much larger.
    2. DNA replication in eukaryotes occurs during a defined phase in the cell cycle.
    3. The Okazaki fragments in eukaryotes are much longer.
    4. There are more replication origins in eukaryotes.
  18. Assume that in the following cross, d+ x e+, the only gametes formed consist of de alleles. This result may be due to
    1. karyogamy
    2. Gene conversion
    3. Reciprocal recombination
    4. Nonreciprocal recombination
    5. Genetic exchange
  19. Which enzyme catalyzes the addition of nucleotides to a growing DNA chain?
    1. Ligase
    2. Primase
    3. DNA polymerase
    4. Telomerase
    5. Helicase
  20. Which structures can be involved in recombination?
    1. Chromatids of sex chromosomes only
    2. Chromatids of homologous chromosomes
    3. Chromatids of nonhomologous chromosomes
    4. Chromosomes in different cells
    5. Any two chromosomes
  21. The helicase proteins break the ________ bonds between the bases that hold the double helix together.
    1. hydrogen
    2. covalent
    3. phosphodiester
    4. glycoside
    5. peptide
  22. Initiation of DNA synthesis requires a RNA primer made by the enzyme
    1. primase.
    2. ligase.
    3. helicase.
    4. gyrase.
    5. endonuclease.
  23. The discontinuous aspect of DNA replication in vivo is caused by
    1. polymerase slippage.
    2. trinucleotide repeats.
    3. the 5' to 3' activity of DNA polymerase.
    4. discontinuous action of helicase.
    5. sister-chromatid exchanges.
  24. Structures located at the ends of eukaryotic chromosomes are called
    1. centromeres.
    2. chromomeres.
    3. duplication mutations.
    4. telomeres.
    5. deletion mutations.