enzymes and digestion

• Enzymes


  Produced by cells and then released into the gut to mix with food
• Digestive Enzymes Break Down Big Molecules

  1. Starch, proteins and fats are broken down into smaller molecules like sugars, amino acids, glycerol and fatty acids

  2. Smaller, soluble molecules can pass through the walls of the digestive system and be absorbed into the bloodstream
• Enzymes


  Catalyse the breakdown of different food molecules
• Carbohydrases


  Convert carbohydrates into simple sugars
• Breakdown of Food


  Catalysed by Enzymes
• Carbohydrases


  • Amylase
• Enzymes used in the digestive system

  • Produced by specialised cells in glands and in the gut lining
• Amylase breaks down starch

  1. Starch

  2. Amylase enzyme

  3. Maltose and other sugars, e.g. dextrins
• Enzymes that catalyse the breakdown of different food molecules

  • Protease
  • Amylase
  • Lipase
• Places amylase is made

  • The salivary glands
  • The pancreas
  • The small intestine
• Liver


  Where bile is produced
• Proteases


  Convert proteins into amino acids
• Bile


  Neutralises stomach acid and emulsifies fats
• Places proteases are made

  • The stomach (it's called pepsin there)
  • The pancreas
  • The small intestine
• Stomach


  • 1) Pummels the food with its muscular walls
  • 2) Produces the protease enzyme, pepsin
  • 3) Produces hydrochloric acid to kill bacteria and provide the right pH for protease enzyme
• Lipases


  Convert lipids into glycerol and fatty acids
• Gall bladder


  Where bile is stored before it's released into the small intestine
• Places lipases are made

  • The pancreas
  • The small intestine
• Pancreas


  Produces protease, amylase and lipase enzymes and releases them into the small intestine
• Small intestine


  • 1) Produces protease, amylase and lipase enzymes to complete digestion
  • 2) Where the digested food is absorbed out of the digestive system into the blood
• The body makes good use of the products of digestion. They can be used to make new carbohydrates, proteins and lipids. Some of the glucose (a carbohydrate) that's made is used in respiration
• Bile


  Neutralises the stomach acid and emulsifies fats
• Large intestine


  Where excess water is absorbed from the food
• Rectum


  Where the faeces (made up mainly of indigestible food) are stored before they bid you a fond farewell through the anus
• Bile's role in digestion

  1. Produced in the liver and stored in the gall bladder before being released into the small intestine

  2. Neutralises the acidic pH from the stomach to make conditions alkaline for enzymes in the small intestine to work properly

  3. Emulsifies fats by breaking them into tiny droplets, increasing the surface area for lipase to work on
• The whole of the digestive system is actually a hole that goes right through the body
• salivary glands


  produce amylace enzyme in the saliva
• gullet


  oesophagus
• Make sure you know the examples of amylase, protease and lipase, and the reactions that they catalyse
• bile


  neutralises stomach acid
• gall bladder


  where bile is stored
• large intestine


  where excess water is absorbed from food
• rectum


  where the faeces are stored before out the anus