Bio1151 Chapter 16 9
  1. The physical structure of nucleic acids such as _ANI_16,5 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 _act_16&C inside.

     
  3. _act_16&B 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               .
     

     
    _act_16&D 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.