Digestion and absorption

• What is digestion

  The process of by which large, insoluble molecules in food are hydrolysed into smaller, soluble molecules that can absorbed across the cell membrane into the the bloodstream.
• What are the three main types of digestive enzymes?

  Carbohydrase - hydrolyse carbohydrates to monosaccarides

  lipases - hydrolyse lipids(fate and oils) into glycerol and fatty acids

  proteases - hydrolyse proteins into amino acids
• digstion of carbohydrates

  • location of digestion - mouth and small intestine
  • amylase ( produced in mouth and pancreas) hydrolyses glycosidic bonds in starch into maltose
  • maltose is then hydrolysed by maltase into a-glucose.
• where is maltase located

  • maltase is a disaccharidase which is found in the cell-surface membranes of the epithelial cells lining the small intestine.
• Lipid digestion

  • lipare are enzymes produces in the pancreas and produced in the lumen of the small intestine.
  • They hydrolyse ester bonds in triglycerides To form fatty acids and glycerol
• protein digestion

  • endopeptidase - hydrolyses the peptide bonds within polypeptide chains
  • Exopeptidase - hydrolyse peptide bonds on the terminal of the polypeptide to produce dipeptides
  • dipeptidase - hydrolyse dipeptides into amino acids. Dipeptidase are membrane-bound being part of the cell-surface membrane of the epithelial cell lining the ilium.