digestion enzymes

• Lipids (fats and oils) are large molecules. During digestion the enzyme lipase breaks them down into fatty acids and glycerol (energy store) . These can be used by the body to provide energy.

  
• Proteins are long chains of amino acids. During digestion the enzyme protease breaks them down into single amino acids (growth) which are small and soluble and can be used by cells to build new proteins.

  
• Starch is a long chain carbohydrate. It is insoluble. During digestion the enzyme carbohydrase (amylase) breaks it down into single molecules of glucose (energy store) which are small and soluble enough to be carried in the blood to the cells for respiration, or to be stored as glycogen in the liver.

  
• Lipids are in oily fish, nuts and seeds, and avocados. They also keep us warm by insulating us and protect our organs
• Proteins are found in legumes and meat/fish. Proteins can be used for energy if we don't have enough carbs or lipids
• Visking tubing limitations ;

  • No blood supply so diffusion gradient cannot be maintained
  • No villi - surface area is too small
  • Too short - tubing should be 6m long