Biomolecules

• Basic structure of 4 major classes of biomolecules

  • Purine / pyrimidines
  • Carbohydrates
  • Lipids
  • Amino acids
• Deoxyribonucleic acid (DNA)

  A long polymer consisting of 4 nucleotide bases: adenine, thymine, guanine, cytosine
• Nucleotides

  Held together by phosphodiester bonds
• DNA

  • Double-stranded
  • Exists as a right-handed helix
  • Has a sugar phosphate backbone linked by phosphodiester bonds
• Amino acids


  Basic structure: H2N-CH-COOH with a side chain (R)
• Amino acid structure

  • Primary structure: H2N-CH-COOH
  • Secondary structure: α-helix, β-sheet
  • Tertiary structure: 3D folding
  • Quaternary structure: multi-subunit protein
• Types of amino acids

  • Aliphatic
  • Sulfur-containing
  • Aromatic
  • Acidic
  • Basic
  • Imino
• Carbohydrates

  Monosaccharides, oligosaccharides, polysaccharides linked by glycosidic bonds
• Lipids

  Located in 3 main compartments: plasma, adipose tissue, biological membranes
• Fatty acids

  • Saturated, unsaturated
  • Melting points vary
• Fluid mosaic model

  Membrane composed of fluid-like lipids and proteins
• Membrane proteins

  • Integral (transmembrane), peripheral, enzymes, channel proteins