1.4 biology

• Hormone


  Protein released by an endocrine gland into the blood to act as a chemical messenger
• Antibodies


  A protein that is involved in defence in animals
• Structural protein


  Proteins in membranes, muscle, bone, hair and nails
• Receptor

  Cell surface protein which allows a cell to recognise specific substrates
• Enzyme


  Protein produced by living cells which acts as a biological catalyst; they speed up chemical reactions and remain unchanged at the end
• Active site


  The position on the surface of an enzyme molecule to which specific substrate molecules can bind
• Substrate


  The shape of the active site is complementary to this
• Each different enzyme acts on only one substrate
• Complementary


  Fitting together like a hand in a glove
• Product


  The substance made by an enzyme-catalysed reaction
• Optimum


  Conditions such as temperature and pH at which an enzyme is most active
• Denature


  A change in the shape of molecules of protein such as enzymes, resulting in them becoming non-functional
• Degradation


  A reaction that breaks large molecules into smaller ones
• Synthesis


  A reaction that builds smaller molecules into larger ones
• Enzyme-substrate complex


  The complex that forms when an enzyme and substrate join, that facilitates the reaction
• Types of protein


  • Structural
  • Hormones
  • Antibodies
  • Receptors
  • Enzymes
• Enzymes have an active site – this is where an enzyme reaction occurs
• The shape of the active site of a molecule is complementary to a specific substrate
• A substrate is the molecule that the enzyme works on
• Enzymes are specific meaning they only work on one type of substrate
• This is because the shape of the active site allows it to only fit with one substrate