Cell Organisation and Enzymes

• What do enzymes do in chemical reactions?

  They catalyse (speed up) chemical reactions
• Why does each enzyme only catalyse one specific reaction?

  Due to the unique shape of its active site
• How do enzymes and substrates interact?

  They fit together like a lock and key
• What effect do high temperatures and extreme pH levels have on enzymes?

  They change the shape of the active site
• What happens to an enzyme when it is denatured?

  It no longer works
• What do digestive enzymes do?

  They break BIG molecules into smaller, soluble ones
• Why do smaller molecules produced by digestive enzymes matter?

  They can pass through the digestive system walls
• What are the three main types of digestive enzymes and their functions?

  • Amylase: breaks down starch into maltose and sugars; produced in salivary glands, small intestine, pancreas
  • Protease: breaks down protein into amino acids; produced in stomach, small intestine, pancreas
  • Lipase: breaks down lipid into glycerol and fatty acids; produced in small intestine, pancreas
• Where is bile produced?

  Bile is made in the liver
• How does bile speed up digestion?

  1. Makes conditions alkaline for better enzyme function
  2. Emulsifies fat for larger surface area for lipase
• What is the optimum temperature for enzyme activity?

  O°C
• What happens to the reaction rate at 45°C?

  The enzyme is denatured
• How does the shape of the active site affect enzyme function?

  A unique shape allows specific substrate binding