Chapter 11 Quiz Videos  Art

Part 2: DNA Structure, Replication, and Variation DNA Replication and Recombination Review
  1. The of DNA strands allows each strand to serve as a for synthesis of the other.
  2. DNA replication in bacteria begins at the of replication and is .
    • The DNA helix is unwound by proteins called which bind to the origin of replication and break the bonds between the bases.
    • Producing of DNA polymers requires a primer made by the enzyme .
    • Polymerization is catalyzed by several DNA polymerases.
    • Chain occurs in the 5' to 3' direction by addition of one nucleotide at a time to the 3' end.
    • DNA synthesis is continuous along the strand of the replication fork, but is discontinuous along the strand. Synthesis is on both strands.
    • The RNA primer is removed by which replaces it with DNA bases.
    • The Okazaki fragments are joined together by DNA , which forms the missing phosphodiester bonds between the fragments.
    Prokaryote DNA synthesis summary.
  3. Eukaryotic DNA synthesis is more complex than that in prokaryotes.
    • Eukaryotic genomes are and contain multiple origins of replication to allow the genome to be replicated in a few hours.
      • Several DNA have been discovered; four partake in replication, the rest are involved in processes.
    • Eukaryotic chromosomes are complexed with , forming that also need to be duplicated during DNA synthesis.
    • Eukaryotic chromosomes are rather than circular, and pose a problem when terminating replication on the strand.
      • Repeating sequences of DNA called are synthesized by the enzyme to prevent chromosome shortening in cells.
    • Homologous in general involves DNA exchange along two chromosomes with sequence homology.
    • DNA recombination can also occur by gene , caused by excision repair of a heteroduplex in meiosis.
bio3400 Home +space -space Nov 15, 2008 Print Print