4 structural levels

• what are the 4 structural levels of proteins?

  primary secondary tertiary quaternary
• what is the primary structure of proteins?

  the sequence of amino acids in the polypeptide chain
• what is the secondary structure of proteins?

  Hydrogen bonds form between the amino acids in the chain.

  This makes it automatically coil into an alpha helix or fold into a beta pleated sheet
• describe the Tertiary structure of proteins?

  • forms the final 3D structure of the protein (for proteins made from a single polypeptide chain)
  • formed by further twisting and folding
  • more bonds form between different parts of the polypeptide chain, including hydrogen bonds and ionic bonds
  • disulfide bridges also form
• what are hydrogen and ionic bonds (tertiary structure)?

  Attractions between negative and positive charges on different parts of the molecule
• describe disulfide bridges (tertiary structure?

  form whenever 2 molecules of the amino acid CYSTEINE come close together- the sulfur atom in one cysteine bonds to the sulfur atom in the other
• Describe the quaternary structure of proteins?

  • the way the polypeptide chains are assembled ttogether
  • the proteins final 3d structure (for proteins made from more than one polypeptide chain eg collagen_
• give examples of proteins made from more than one polypeptide chain?

  collagen, insulin, haemoglobin