Digestive system

• catalysts speed up reactions without being used up or changed themselves
• enzymes are biological catalysts
• the active site is the part of an enzyme that binds to its substrate
• test for starch (a carbohydrate) is iodine
• If starch if present the colour will change from orange to blue/black
• Test for protein: biuret solution
• If protein is present it will change blue to purple
• Protease breaks down proteins into amino acids
• Where is protease produced?

  • stomach
  • small intestine
  • pancreas
• Test for lipids (fats): Sudan 111 or ethanol
• If lipids (fats) are present it will turn clear to a cloudy white emulsion
• Lipase breaks down lipids (fats) into glycerol and fatty acids
• Where is lipase found?

  • pancreas
• If sugar is present it will turn from blue to brick red