enzymes

• What are large proteins that catalyse reactions called?

  Enzymes
• What is the lock and key theory of enzymes?

  • Enzyme's active site has a specific shape
  • Enzyme (lock) catalyses specific reactions
  • Substrate (key) fits into the active site
  • Enzyme can break down or bind molecules
  • Active site accepts another substrate after reaction
• How does temperature affect enzyme activity?

  Higher temperature increases reaction rate
• What is the optimum temperature for enzymes?

  When the reaction works fastest
• What happens to an enzyme when it is denatured?

  It stops working
• How does pH affect enzymes?

  Different enzymes have different optimum pH values
• Why are enzymes adapted to different pH environments?

  To work well in varying pH conditions
• What are the digestive enzymes and their functions?

  • Amylase:
  • Sites: Salivary glands, pancreas, small intestine
  • Reaction: Starch -> maltose
  • Protease:
  • Sites: Stomach, pancreas, small intestine
  • Reaction: Proteins -> amino acids
  • Lipases:
  • Sites: Pancreas, small intestine
  • Reaction: Lipids -> fatty acids and glycerol
• test for lipids

  ethanol. colour change from clear to cloudy white
• test for sugar

  benedicts. colour change from blue to red
• test for starch

  iodine. colour change from brown to blue-black
• test for protein

  biuret. colour change from blue to purple