Human Digestive System and Enzymes

• Steps of Digestive System

  1.Mouth- breaks down food mechanically

  2.Oesophagus

  3.Stomach- HCL and enzymes that chemically breaks down food

  4.Small Intestine- Nutrients like glucose are absorbed into bloodstream by villi as starch is too large

  5.Large Intestine- Water is absorbed into bloodstream

  6.Pancreas- secretes amylase which breaks down starch into glucose in the small intestine

  7.Liver- produces bile, which is stored in the gall bladder before going to the small intestine. Bile emulsifies lipids to form droplets, increasing their surface area
• Enzymes

  Biological catalysts which spec up rates of reaction without being used up
• Made of proteins meaning ribosomes make them out of amino acids
• Active Site

  Enzyme is specific to its active site which fits lock and key theory
• How do enzymes denature?

  High Temps and PH
• Amylase


  Breaks down starch into sugars.Made in mouth,small intestine and pancreas.Works in mouth and small intestine
• Protease

  Breaks down proteins into amino acids.Made in stomach pancreas and small intestines.Works in stomach and small intestine
• Lipase


  Lipids break down into fatty acids and glycerol.Made in pancreas and small intestine.Works in small intestine
• Other Chemicals in Digestive System

  -Bile which is made in liver and works in small intestine.Function:Emulsifies fat to provide larger surface area and neutralise acid to give optimum PH for enzymes to function

  -HCL which is made and used in stomach.Function is that it destroys bacteria and gives optimum PH for protease enzyme to work