Digestive enzymes

• Enzymes


  Catalyze chemical reactions, speed them up
• Enzymes


  • Large protein molecules
  • Have a groove on their surface called the active site
  • The active site is where the substrate attaches
• Substrate


  The molecule that the enzyme breaks down
• Substrate fits into active site


  Enzyme can break down substrate
• Substrate does not fit into active site


  Enzyme cannot break down substrate
• Lock and key theory


  Enzymes are specific, the substrate must fit perfectly into the active site
• Protein digestion


  Proteases break down proteins into amino acids
• Proteases


  • Found in stomach, pancreatic fluid, small intestine
• Proteins


  Long chains of amino acids
• Starch digestion


  Carbohydrases break down starch into simple sugars
• Amylase


  • Enzyme that breaks down starch, found in saliva and pancreatic fluid
• Starch


  Chain of glucose molecules
• Lipid digestion


  Lipase breaks down lipids into glycerol and fatty acids
• Lipase


  • Found in pancreatic fluid and small intestine
• Lipids


  Molecule of glycerol attached to three fatty acids
• Bile


  • Made in the liver, stored in the gallbladder
  • Not an enzyme, but helps speed up lipid digestion by lipase
  • Converts large lipid droplets into smaller droplets, increasing surface area
  • Alkaline, neutralizes stomach acids in small intestine