Macromolecules

• Nucleic Acids


  Informational Macromolecules, store hereditary info
• Nucleic Acids


  • Only molecules that can copy themselves
• Types of Nucleic Acids

  • DNA (deoxyribonucleic acid)
  • RNA (ribonucleic acid)
• Nucleic Acids


  Polymers of monomers called nucleotides linked together by dehydration synthesis
• Parts of a Nucleotide

  • Nitrogenous base
  • Pentose (5 C sugar)
  • Phosphate group
• Nitrogenous Bases


  • Adenine (A)
  • Guanine (G)
  • Cytosine (C)
  • Thymine (T) (found only in DNA)
  • Uracil (U) (found only in RNA)
• Nitrogenous Bases


  • Divided into 2 families: Purines and Pyrimidines
• Pyrimidines


  1. member, single ring of carbon and nitrogen
• Pyrimidines


  • Cytosine (C)
  • Thymine (T)
  • Uracil (U)
• Purines


  Larger, double ring, 5-member ring fused to pyrimidine
• Purines


  • Adenine (A)
  • Guanine (G)
• Pentose

  Ribose in the nucleotides of RNA, and deoxyribose in DNA
• Deoxyribose

  One oxygen atom missing from ribose
• The only difference between DNA and RNA is the type of pentose sugar
• DNA is double stranded helix, RNA is single stranded
• DNA is found in the nucleus, RNA is found in the nucleus and cytoplasm
• Phosphate Group


  Attached to the number 5 carbon of the sugar forming a nucleoside monophosphate or nucleotide
• Nucleotides can perform important functions as individual molecules, e.g. ATP, NAD, FAD
• Polynucleotide


  Another name for a nucleic acid
• Phosphodiester Linkages


  Covalent bonds that join the monomers in a polynucleotide
• The backbone of a polynucleotide has a repeating pattern of sugar-phosphates
• In DNA, the nitrogenous bases stick out from the backbone and can vary along the backbone
• In RNA, the polynucleotide chain is single stranded
• In DNA, the two polynucleotide chains are antiparallel, running in opposite directions
• In DNA, the two strands are held together by hydrogen bonds between the nitrogenous bases
• Adenine-Thymine Pairing

  2 hydrogen bonds
• Guanine-Cytosine Pairing

  3 hydrogen bonds