proteins

• dipeptides are formed via condensation reaction, a peptide bond is between the OH in the carboxyl group and H in the amine group (c-n)
• primary structures

  • specific order of amino acids
  • polypeptide chain
• secondary structure

  • sequence of amino acids causes molecules to bend into shape either alpha helix or beta pleated structure
  • hydrogen bonds hold secondary structure
  • hydrogen bonds are made between the amine groups and the oxygen in the carboxyl groups
• tertiary structure

  • the further folding of the protein creates a unique 3d shape , held together by hydrogen , ionic and disulfide bonds
  • bonds occur in the r groups of different amino acids
  • disulfide bonds only sometimes occur as there has to be sulfur in the r group
• quaternary structure and example

  • its a protein made of more than one polypeptide chain
  • haemoglobin has 4 polypeptide chains
• haemoglobin is an example of a quaternary structure with 4 polypeptide chains
• draw an amino acid?

  amino acid

  
• what happens when an protein/enzyme denatures?

  • if a protein denatures then it means the bond in the tertiary or quaternary structure breaks and the unique 3d shape is lost
• channel proteins are involved in facilitated diffusion only

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