Classification of proteins

• how can proteins be classified

  according to their structures
• what do fibrous proteins do

  they carry out structural functions
• give examples of fibrous proteins

  • keratin
  • collagen
• what is collagen made up of

  • 3 alpha helix polypeptide chains
  • twisted into rope-like strands
  • held together by hydrogen bonds
• describe fibrous proteins

  • tough
  • non-specific (no complicated structure)
  • insoluble
• what shapes do globular proteins have

  circular shapes
• what can globular proteins be

  • tertiary proteins
  • or quaternary proteins
• describe the properties of globular proteins

  • compact + folded into spherical molecules
  • have a specific shape
  • soluble in water