Save my exams notes

• What is digestion?

  A process of breaking down food
• What happens to large, insoluble biological molecules during digestion?

  They are hydrolysed into smaller, soluble molecules
• Why are enzymes essential for digestion?

  They catalyse the hydrolysis of food molecules
• What are small soluble molecules produced during digestion?

  Glucose and amino acids
• How are glucose and amino acids used by cells?

  For energy or to build other molecules
• Into what are proteins hydrolysed?

  Amino acids
• Into what are carbohydrates hydrolysed?

  Simple sugars
• Into what are lipids hydrolysed?

  A mixture of glycerol and fatty acids
• What glands produce digestive juices in the human digestive system?

  Salivary glands and pancreas
• What is the role of the stomach in digestion?

  Site of digestion
• What does the liver produce?

  Bile
• What is the site of absorption in the human digestive system?

  Small intestine
• What is the site of water reabsorption in the human digestive system?

  Large intestine

  
• What does it mean that enzymes are substrate specific?

  Different enzymes digest different biological molecules
• What are the three main types of digestive enzymes?

  Carbohydrases, proteases, and lipases
• What does the suffix 'ase' indicate about a molecule?

  It is likely an enzyme
• Where does carbohydrate digestion take place?

  Mouth and small intestine
• What does amylase do?

  Hydrolyses starch into maltose

  
• Where is amylase produced?

  Salivary glands, pancreas, small intestine
• What is maltase's function?

  Hydrolyses maltose into glucose

  
• Where is maltase found?

  Cell-surface membranes of epithelial cells
• What do sucrase and lactase do?

  Hydrolyse sucrose and lactose respectively
• How does the structure of the small intestine aid absorption?

  It has folds and microvilli to increase surface area
• What is the role of endopeptidases in protein digestion?

  Hydrolyse peptide bonds within proteins

  
• What is the pH of the stomach during protein digestion?

  Low and acidic
• What happens to partially digested food after the stomach?

  It moves into the small intestine
• What does pancreatic juice contain?

  Endopeptidases and exopeptidases

  
• What do exopeptidases do?

  Hydrolyse peptide bonds at the ends of polypeptide chains
• What is the function of dipeptidases?

  Hydrolyse dipeptides into amino acids

  
• Where are dipeptidases found?

  Cell surface membrane of epithelial cells
• What is emulsification in lipid digestion?

  Breaking down fat droplets into smaller ones

  
• What is the role of bile salts in lipid digestion?

  They aid emulsification of fats

  
• Where does lipid digestion occur?

  In the lumen of the small intestine

  
• What do lipase enzymes break down lipids into?

  Glycerol and fatty acids
• Where are lipase enzymes produced?

  In the pancreas
• What is the effect of extreme pH on enzyme activity?

  It can change the shape of the active site

  
• How can the effect of pH on enzyme reaction rates be investigated?

  By using amylase to break down starch

  
• What is used as an indicator for starch presence?

  Iodine solution

  
• What does a blue-black color indicate when testing for starch?

  Starch is still present
• What does an orange-brown color indicate when testing for starch?

  All starch has been digested