Proteins

• What are proteins made up of?


  Amino acids
• Structure of Amino Acids

  A) Carboxyl group

  B) Amino Group

  
• What type of reaction happens when two amino acids join together?

  A condensation reaction
• What is the by-product of a condensation reaction?


  Water
• What is a polypeptide?

  More than two amino acids joined together
• What is the primary structure of a protein?

  The order of amino acids
• What happens in the secondary structure of a protein?

  Peptide bonds form between adjacent amino acids & R groups interact to form hydrogen bonds
• What are the two types of secondary structures?

  Alpha helix & Beta pleated sheet
• What is the tertiary structure?

  When the folded polypeptide folds again
• What are the three bonds in the tertiary structure?


  Hydrophobic, Ionic & Disulphide
• What are hydrophobic interactions?

  When hydrophobic R groups associate with others to be more stable
• What is the secondary structure?

  The shape the chain of amino acids takes
• What is an ionic bond?

  The electrostatic attraction between the charged side chains of amino acids
• What are disulphide bonds?

  Covalent bonds between two cysteine R groups (only amino acid with sulphur)
• How are ionic bonds broken?

  pH changes
• How are disulphide bonds broken?

  Temperature changes
• What is a quaternary structure?

  More than one polypeptide chain together. Each chain is the subunit of a protein
• Globular vs Fibrous Proteins

  A) soluble

  B) insoluble

  C) Collagen

  D) Keratin

  E) Structural

  F) Functional

  G) spherical

  H) Long strands

  I) wide

  J) limited

  K) Haemoglobin

  L) insulin

  
• How do we break polypeptide chains?

  By adding water (hydrolysis)
• Structure of Haemoglobin:

  • Globular protein --> round shape
  • Conjugated protein --> has prosthetic group
  • Has prosthetic group (a non protein group)
  • Has 4 subunits (chains)
• What bonds are involved in the tertiary structure?

  • Some R groups, attract / repel
  • disulfide bonds between, cysteine / SH / S (atoms) ;
  • hydrogen / H, bonds
  • ionic bonds between, oppositely charged R groups
  • hydrophilic R groups, on the outside of molecule / in contact with water (molecules)
  • hydrophobic R groups, on inside of molecule / shielded from water (molecules
• What is the structure of collagen like?

  • Have three polypeptide chains wrapped around each other
  • Every third amino acid is glycine
  • Hydrogen bonds form between the polypeptide chains