DNA Replication


Since DNA is the genetic code for the synthesis and development of whole organisms, it must be copied exactly from one generation to the next. This is achieved by self-replication, using a semi-conservative mechanism in which each strand acts as a template for the synthesis of a new strand. Each new DNA molecule contains one of the original strands in addition to a new strand (hence the name semi-conservative). DNA replication takes place before the chromosomes duplicate during the process of mitosis and meiosis.

  • The enzyme DNA helicase breaks the hydrogen bonds holding the base pairs together and 'unzips' part of the DNA double helix, revealing two strands.
  • The enzyme DNA polymerase moves along each strand, which acts as a template for the synthesis of a new strand.
  • DNA polymerase catalyses the joining of free deoxyribonucleotides to each of the exposed original strands, according to base pairing rules, so that new complementary strands form
  • The process of unzipping and


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