Catalysts and enzymes

• whats an enzyme?

  proteins that act as biological catalysts - they speed up chemical reactions in living organisms
• What’s a catalyst?


  A substance that increases the rate of a chemical reaction without being consumed in the process.
• Give examples of an enzyme:

  • Lipase
  • Carbohydrase
  • Amylase
• What does each enzyme break down?

  lipase - lipids

  carbohydrase - carbohydrates

  Protease - proteins

  Amylase - starch
• Make the enzyme properties :

  • They’re all large proteins
  • There’s a space within the protein molecule called the active site
  • Each enzyme catalyses a specific reaction
  • The work best at a specific temperature and pH called the optimum
• The lock and key theory is a model used to explain how enzymes work :

  The chemical that reacts is called the substrate (key) and it fits into the enzymes active site (lock)
• what makes enzymes denature?

  High temperature, extreme pH levels, and certain chemicals can denature enzymes.
• why is it bad if the enzyme denatures?

  it can no longer work, once it has denatured, it’s changed shape, so it cannot fit into the active site (the lock and key no longer fit together)
• where are enzymes produced in the body?

  • specialised cells in glands
  • Specialised cells in the lining of the gut
• how do enzymes break down food?


  Catalysis
• give the process of how enzymes break down food:

  
  

  the enzymes pass out of the cells into the digestive system

  
  

  they come into contact with food molecules

  
  

  they catalyse the breakdown of large insoluble food molecules into smaller soluble molecules
• Amylase

  • Is produced in the salivary glands and the pancreas
  • Is a carbohydrase that breaks down starch into sugar (maltose)
  • Starch —-> maltose
• Protease

  • Is produced in the stomach, pancreas and small intestine
  • Breaks down proteins into amino acids
  • Protein —-> peptides or amino acids
• Lipase

  • Is produced in the pancreas and small intestine
  • Breaks down lipids (fats) into fatty acids and glycerol
  • Fats —-> fatty acids + glycerol