Digestion

• How are carbohydrates digested?

  • Amylase in salivary glands hydrolysis polysaccharides into disaccharides
  • Membrane bound enzymes in the illeum such as maltose hydrolyse disaccharides into saccharides
• How are monosaccharides and amino acids absorbed?

  • Sodium ions are actively transported from the epithelial cells to the blood
  • This creates a concentration gradient
  • sodium ions move from the illeum lumen into the epithelial cells by fasciliatated diffusion
  • The sodium attaches to the glucose and cotransports the glucose into the epithelial cell with it
  • This high concentration of glucose then diffuses into the blood by fascilitated diffusion
• How are proteins digested?

  • Endopeptidases hydrolyse peptide bonds in the middle of a chain
  • Exopeptidases hydrolyse peptide bonds at the end of a chain
  • Membrane bound dipeptidases hydrolyse peptide bonds between 2 amino acids
• How are lipids digested?

  • Lipase in the pancreas goes to the small intestine and hydrolyse Ester bonds in triglycerides into monoglycerides and fatty acids
  • Bile salts are produced in the liver and emulsify lipids into micelles for a larger surface area
• How are micelles formed?

  • Formed from Bile salts
  • Contain fatty acids, glycerol and monoglycerides
• Lipids absorption

  • Non-polar micelles diffuse across the epithelial membrane
  • Fatty acids and monoglycerides are modified back into triglycerides
  • Fats combine with proteins in the golgi to form chylomicrons
  • Chlymicrons vesicles enter the blood 
• What is the process of the test tube elisa test?

  • Antigen is bound to bottom of the test tube
  • Complimentary antibodies added
  • Second antibody with an enzyme for colour change is added, complimentary to the first antibody
  • Substrate for the enzyme is added, if the antibody is bound to antibody and antigen, there will be a colour change
  • Wash after each