Unit 3: Genetics Extras  Study Guide

Chapter 16 The Molecular Basis of Inheritance Review
  1. The physical structure of nucleic acids such as RNA or was discovered by Watson and Crick from photos of crystallography made by Rosalind Franklin.
  2. DNA is a double , with the sugar-phosphate backbones on the outside, and pairs of bases on the inside.
  3. Weak bonds form between the complementary base pairs: (A) always pairs with (T), and (C) always pairs with (G).
  4. The base-pairing rules are used for DNA : each strand acts as a for building a strand.
  5. The replication occurs in three phases: , , and .
    Summary: DNA replication
  6. Base-pairing is about 99.999% accurate, an error occurs about 1 in base pairs. DNA can "proofread" during polymerization and replace most incorrect nucleotides.
  7. Uncorrected DNA can be repaired by nucleotide repair.
  8. The overall error rate is about 1 in 10 nucleotides, or 99.99999999% accurate.
  9. The ends of linear eukaryotic chromosomes get with each round of replication.
    • Each chromosome terminates in a , that postpones the erosion of genes near the ends.
    • Eukaryotic cells contain the enzyme to lengthen telomeres in gametes.
  10. Eukaryotic DNA is packaged with proteins to form , which condense into visible chromosomes during mitosis.
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