2.2 DNA Replication

Semi-Conservative Replication

  • For semi-conservative replication to take place, 4 conditions must occur
  • @@Nucleotides@@ of all 4 bases must be present
  • Both @@strands act as DNA template@@s
  • @@DNA polymerase@@ present
  • A source of @@chemical energy@@ present

Process of Transcription

  • DNA double helix @@unzipped by helicase@@
  • @@Hydrogen bonds broken@@
  • RNA nucleotides @@align next to their complementary base@@ of template strands forming @@hydrogen bonds@@
  • @@Uracil replaces thymine@@ in RNA
  • RNA polymerase @@joins adjacent nucleotides@@ in @@condensation reaction@@
  • Forming @@phosphodiester bonds@@
  • When RNA polymerase reaches STOP codon @@mRNA or premRNA detaches from DNA@@
  • @@Splicing@@, removing introns using spliceosomes
  • @@mRNA leaves nucleus@@ via nuclear pores

Process of Translation

 1. @@Small and large ribosome subunits@@ join on mRNA  2. tRNA that is free-floating has an anticodon at 1 end and an area for amino acids to join  3. A tRNA molecule @@bonded to the specific amino acid@@ enters ribosome via the @@A point@@  4. It @@joins the codon that is complementary to the anticodon@@  5. The @@ribosome moves along@@ 1 codon  6. @@Another tRNA enters@@ and joins to its codon  7. The amino acids from each tRNA join via @@condensation reaction to form peptide bonds with the use of ATP@@  8. The first tRNA amino acid @@exits via the E point@@  9. A @@new tRNA enter@@s

  1. This continues until @@STOP codon is reached@@
  2. The polypeptide breaks off the ribosome subunits remove from mRNA
  3. tRNA is released

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