Chemical digestion

• Chemical digestion : the breakdown of large insoluble molecules into small soluble molecules
• Chemical digestion produces small soluble molecules that can be absorbed
• carbohydrase:

  1. Amylase (salivary glands) : starch to maltose (mouth)
  2. Amylase (pancreas) : starch to maltose (small intestine)
  3. Maltase : maltose to glucose (membranes of small intestine epithelium lining)
• Protease: protein to amino acids

  • pepsin : stomach (acidic)
  • trypsin : pancreas to small intestine (alkaline)
• Lipase:

  • lipase (pancreas) : lipids to glycerol and fatty acids (small intestine)
• hydrochloric acid in gastric juice:

  • killing harmful microorganisms in food
  • providing an acidic pH for optimum enzyme activity
• bile is an alkaline mixture that neutralises the acidic mixture of food and gastric juices entering the duodenum from the stomach, to provide a suitable pH for enzyme action. It also emulsifies lipids