5. Digestion

Cards (19)

  • Define hydrolysis
    The breaking of bonds by addition of h2o
  • What is the function of salivary glands
    Secrete saliva - mix of amylase, water and ions
  • What is the function of the pancreas
    Pancreatic juice - enzymes in an alkaline solution
  • Function of small intestine
    Main area of secretion of enzymes and bile - dueodenum
    Absorption- ileum
  • Where does starch digestion begin
    Mouth
  • Explain the first step of digestion of starch (mouth)
    Salivary glands release amylase which hydrolyses starch into maltose by breaking glycosidic bonds
  • What happens to starch in the stomach
    Salivary amylase is denatured so pancreatic amylase is used to hydrolyse remaining maltose
  • What happens to starch on the brush border of small intestines
    Maltase is found and hydrolyses maltose into glucose which is then absorbed
  • Which enzymes digest proteins
    Peptidases
  • What do endopeptidases hydrolyse
    Peptide bonds in the middle of chain making a larger surface area for exopeptidases
  • What do exopeptidases do
    Hydrolyse peptide bonds at the end of the chain producing dipeptides or amino acids
  • What digests lipids
    Lipases
  • Where does lipid digestion begin
    Duodenum
  • What is emulsification
    Bile salts combine with lipid droplets to make them smaller which increases surface area.
  • How are lipids then absorbed
    After emulsification lipases hydrolyse them into fatty acids and glycerol which combine with bile salts to form micelles. micelles transport contents to epithelial cells and release into the cell. Where they recombine to form triglycerides and combine with a protein to form chylomicrons
  • Why are micelles beneficial for lipid absorption
    They are water soluble so can transport contents to membrane
  • What are chylomicrons
    Lipoproteins
  • What molecules can be absorbed through the stomach wall
    Water and ethanol
  • What is co transport
    When a sodium ion is diffused into the cell with another molecule through a contransport protein.