1.3

• Protein


  Anorganic compound that is made of one or more chains of amino acids

  
• Amino Acid


  Building blocks of protein - contain an amino group carboxylic group, R group and hydrogen attached to a central carbon

  
• Dipeptide


  2 amino acids joined together

  
• peptide bond


  The bond that forms between the carboxyl group of one amino acid and the amino group of another amino acid

  
• enzyme


  A protein serving as a catalyst; a chemical agent that changes the rate of reaction without being consumed by the reaction

  
• primary structure


  The first level of protein structure; the specific sequence of amino acids making up a polypeptide chain.

  
• secondary structure


  The second level of protein structure; the regular local patterns of coils or folds of a polypeptide chain for instance alpha helix and beta pleated sheet. Held together by hydrogen bonds.

  
• tertiary structure


  3D shape of single polypeptide using hydrogen and ionic bonds as well as disulphide bridges

  
• disulphide bridge


  The S-S linkage, i.e. between two sulfur atoms, that forms during the cross-linking of amino acids during protein synthesis.

  
• denature


  A change in the shape of a protein (such as an enzyme) that can be caused by changes in temperature or pH (among other things).

  
• hydrogen bond


  A type of weak chemical bond formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule.

  
• Side chain or R group


  The unique chemical feature of each amino acid that differentiates one amino acid from another.

  
• Conjugated protein


  A protein with an attached non-protein molecule (prosthetic group)- for instance the iron in haemoglobin.

  
• Collagen


  A fibrous protein with little tertiary structure that is found in connective tissue

  
• Haemoglobin


  A globular protein that is involved in the transport of oxygen