Structure of DNA an RNA

• Basic functions of DNA and RNA

  DNA = Holds genetic information which codes for polypeptides

  RNA = Transfers genetic information from DNA to ribosomes
• Describe how nucleotides join together to form polynucleotides

  • Condensation reaction, removing water molecules
  • Between phosphate groups of one nucleotide and deoxyribose/ribose of another
  • Forming phosphodiester bonds
• Describe the structure of DNA

  • Polymer of nucleotides
  • Each nucleotide formed from deoxyribose, a phosphate group, and a nitrogenous base.
  • Phosphodiester bonds join adjacent nucleotides
  • 2 polynucleotide chains held together by hydrogen bonds
  • Between specific complementary base pairing
  • Double Helix
• Describe the structure of mRNA

  • Polymer of nucleotides
  • Each nucleotide is formed from ribose, a phosphate group, and a nitrogenous base
  • Bases - Uracil instead of thymine
  • Phosphodiester bonds join adjacent nucleotides
  • Single strand
• Suggest how the structure of DNA relates to its functions

  Two strands = Both can act as a template for semi-conservative replication

  Hydrogen bonds between bases are weak = Strands can be separated for replication

  Complementary base pairing = accurate replication

  Many H-bonds between bases = Stable/Strong molecule

  Double helix with sugar phosphate backbone = Protects bases/H-bonds

  Long Molecule = Stores lots of genetic information

  Double Helix = Compact