Please enable JavaScript.

Coggle requires JavaScript to display documents.

Chapter 16 - Coggle Diagram

- - - - The copying of DNA is called DNA replication
        
        Since the two strands of DNA are complementary, each strand acts as a template for building a new strand in replication
        
        This yields two exact replicas of the “parental” molecule
        
        Watson and Crick’s semiconservative model of replication predicts that when a double helix replicates, each daughter molecule will have one old strand
        
        Replication begins at particular sites called origins of replication, where the two DNA strands are separated, opening up a replication “bubble”
- - - - –The base composition of DNA varies between species
      - –In any species the number of A and T bases is equal and the number of G and C bases is equal
      - Maurice Wilkins and Rosalind Franklin used a technique called X-ray crystallography to study molecular structure
        
        Franklin produced a picture of the DNA molecule using this technique
        
        The pattern in the photo suggested that the DNA molecule was made up of two strands, forming a double helix
        
        Watson built a model in which the backbones were antiparallel
        
        Watson and Crick thought the bases paired like with like (A with A, and so on), but such pairings did not result in a uniform width
        
        Realized the pairings were A-T and C-G
- - - - Topoisomerase relieves the strain of twisting of the double helix by breaking, swiveling, and rejoining DNA strands
        
        The initial nucleotide chain is a short R N A primer
        
        This is synthesized by the enzyme primase
        
        Enzymes called DNA polymerases catalyze the synthesis of new DNA at a replication fork
        
        During interphase a few regions of chromatin (centromeres and telomeres) are highly condensed into heterochromatin
- - - - The lagging strand is synthesized as a series of segments called Okazaki fragments, which are joined together by DNA ligase
        
        he proteins that participate in DNA replication form a large complex, a “DNA replication machine”
        
        In mismatch repair of DNA, repair enzymes replace incorrectly paired nucleotides that have evaded the proofreading process
        
        In nucleotide excision repair, a nuclease cuts out and replaces damaged stretches of DNA
        
        Eukaryotic chromosomal DNA molecules have special nucleotide sequences at their ends called telomeres
        
        DNA is precisely combined with proteins in a complex called chromatin
        
        1 more item...