Structure of digestive system and digestive enzymes

• What are the two functions of the human digestive system?

  • To break down complex food substances
  • provides the very large surface area for maximum absorption of food.
• Where does the digestion of carbohydrates begin?


  The mouth
• What happens in the mouth during digestion?

  The digestion of carbohydrates begin.
• What happens in the stomach during digestion?


  Begins the digestion of protein ; small molecules such as alcohol absorbed
• Where does the digestion of protein begin?


  The stomach
• What happens in the small intestine?


  Continues the digestion of carbohydrate and protein and begins the digestion of lipids
• What is the duodenum?


  the first part of the small intestine
• What happens in the ileum?


  The digestion of carbo and proteins into single sugars and amino acids is complete.

  Absorption of single sugars, amino acids and fatty acids and glycerol.
• what is the lieum?


  the last part of the small intestine
• What happens in the large intestine?


  Absorption of water and electrolytes and producing and absorbing vitamins
• What do digestive enzymes do?


  They break down big molecules e.g. starch, proteins and fats
• Why do big molecules such as start and fats get broken down?

  they’re too big to pass through the walls of the digestive system so the digestive enzymes brea them down into smaller ones like sugars (e.g. glucose), amino acids , glycerol and fatty acids.

  The smaller, soluble molecules can pass easily through the walls of the digestive system allowing them to get absorbed into the bloodstream.
• What are villi in the small intestine?


  Small finger-like projections that increase surface area for absorption.
• Where do most digested food pass through?

  The epithelial cells of the gut wall and is carried by blood to the liver.
• Where do digested lipids pass through?


  pass through the gut wall and enter the lacteals (the lymphatic vessels of the small intestine that absorb digested fats)
• what secretion is released into the duodenum?


  bile
• What is an active site?


  The region of an enzyme where substrate molecules bind and a chemical reaction takes place
• what is the purpose of bile?


  emulsifies lipids which breaks them down. this helps with digestion.
• What breaks down carbohydrates?

  carbohydrase
• What breaks down starch?


  amylase
• What does carbohydrates get broken down into?


  simple sugars e.g. glucose
• What does starch get broken down into?


  glucose
• What breaks down protein?


  protease
• what does protein get broken down into?


  amino acids
• What breaks down lipid?


  lipase
• What does lipid get broken down into?


  fatty acids + glucerol
• what is a substrate?


  the substance on which an enzyme can act
• where is amylase produced?


  the salivary glands
• Where is protease produced?


  the pancreas
• where is carbohydrase produced?


  Pancreas
• where is lipase produced?


  Pancreas and small intestine.