Digestion And Absorption

• What is digestion?

  Hydrolysis of large, insoluble molecules into smaller, soluble ones
• Why are enzymes essential for digestion?

  They catalyse the hydrolysis of biological molecules
• What is the function of small soluble molecules produced by digestion?

  Provide energy or build other molecules
• What are proteins hydrolysed into?

  Amino acids
• What are carbohydrates hydrolysed into?

  Simple sugars
• What are lipids hydrolysed into?

  Glycerol and fatty acids

  
• Which parts of the human digestive system produce digestive juices?

  Salivary glands and pancreas

  
• Where does digestion primarily take place?

  The stomach and small intestine
• Which organ produces bile?

  The liver
• Where does absorption primarily occur in the digestive system?

  Small intestine
• What is the function of the large intestine?

  Water reabsorption

  
• What does it mean for enzymes to be substrate specific?

  Different enzymes digest different biological molecules
• What are digestive enzymes classified as?

  Extracellular enzymes
• What are the three main types of digestive enzymes?

  Carbohydrases, proteases, and lipases
• What is a common suffix used for enzyme names?

  'ase'
• Where does carbohydrate digestion take place?

  Mouth and small intestine

  
• What does amylase hydrolyse starch into?

  Maltose

  
• What enzyme hydrolyses maltose into glucose?

  Maltase

  
• Where is amylase made?

  Salivary glands, pancreas, small intestine
• What type of enzyme is maltase?

  Disaccharidase
• Where is maltase found?

  Cell-surface membranes of epithelial cells lining the small intestine
• Name two other disaccharidases found in the epithelial cells of the small intestine.

  Sucrase and lactase
• What do sucrase and lactase hydrolyse respectively?

  Sucrose and lactose
• What feature of the small intestine increases the surface area for absorption?

  Folded lining and microvilli
• Where does protein digestion begin?

  Lumen of the stomach
• What enzyme begins protein digestion in the stomach?

  Endopeptidase

  
• Why is the pH in the stomach acidic?

  Due to secretion of hydrochloric acid
• What is the purpose of fluid secreted by the pancreas?

  Neutralize acidic mixture, increase pH
• What enzymes are contained in pancreatic juice?

  Endopeptidases and exopeptidases

  
• Where are dipeptidase enzymes found?

  Cell surface membrane of epithelial cells
• What is the difference between endopeptidases and exopeptidases?

  Endopeptidases act within, exopeptidases act at ends
• What do dipeptidases hydrolyse?

  Dipeptides into amino acids

  
• What is emulsification?

  Breaking large fat droplets into smaller ones
• Where are bile salts made?

  In the liver
• Where is bile stored?

  In the gallbladder
• Why is emulsification important for lipid digestion?

  Increases surface area for lipase action

  
• Where does lipid digestion take place?

  Lumen of the small intestine
• What do lipase enzymes break down lipids into?

  Glycerol and fatty acids

  
• What happens to an enzyme outside its optimum pH?

  Active site shape may change
• What happens to the enzyme's ability to bind to its substrate at extreme pH concentrations?

  It is disrupted