Digestion Enzymes S2M2

  1. Proteins are broken down by
    Proteases into Amino acids and di/tripeptides
  2. Starch is broken down by
    Glycosidases into glucose
  3. Oligosaccharides are broken down by
    Glycosidases into monosaccharides
  4. Triglycerides are broken down by
    Lipases into fatty acids
  5. Nucleic acids are broken down by
    Nucleases into nucleosides and bases
  6. What are the three enzymes found in salivary glands
    • alpha-Amylase
    • Lysozyme
    • Lingual lipase
  7. Alpha-Amylase in the salivary glands has what effect
    Breaks down alpha-1,4 glycosidic bonds in starch and glycogen
  8. Amylase in the salivary glands eventually forms
    • Maltose
    • Maltotriose
    • Dextrins
  9. What effect does lysozyme in the salivary glands have
    Cleaves beta-1,4 glycosidic bonds in gram positive bacteria
  10. Stomach juice has what pH and action
    • pH - 1.5-3.0
    • Antibacterial
    • Denatures proteins
    • Creates optimal pH for pepsin
  11. Gastric lipase breaks down
    Short fatty acids (breast milk) producing diacylglycerol and fatty acids
  12. What is the optimal pH for Pepsin endopeptidase
  13. What is the effect on digestion when a total gastrectomy is done
    • Mild digestion problems
    • Increase risk of intestinal infections
    • Vit B12 supplements required (lack intrinsic factor)
    • Protein and fats are still digested
  14. Trypsin secreted from the pancreas targets what specific site for digestion
    • Carboxy side of Lys and Arg
    • (Similar to carboxypeptidase b)
  15. Chymotrypsin secreted from the pancreas targets what specific site for digestion
    Carboxy side of hydrophobic amino acids (same as carboxy peptidase a)
  16. Elastase secreted from the pancreas targets what specific sites in digestion
    Carboxy side of small amino acids
  17. Carboxypeptidase A secreted from the pancreas targets what specific sites in digestion
    Cleaves hydrophobic amino acids at the carboxy terminal (same as chymotrypsin)
  18. Carboypeptidase B secreted from the pancreas targets what specific sites in digestion
    Cleaves basic amino acids (Lys, Arg) at the carboxy terminal (similar to trypsin)
  19. Lipase is a major enzyme of fat digestion that requires what substituents to help
    • Co-lipase - Anchors to the surface of fat droplets
    • Bile salts - Decreases fat droplet size
  20. Phospholipases digest
  21. Absence of bile salts results in
    • Steatorrhea (abnormal amounts of fats in feces)
    • Increase risk of deficiencies in fat soluble vitamins
  22. What enzymes complete protein digestion
    Aminopeptidases found in intestinal brush border cells
  23. Aminopeptidases are dependent on
  24. Sucrase an enzyme in the intestines has what effect
    Breaks down sucrose to glucose and fructose
  25. Lactase an enzyme found in the intestines has what effect
    Breaks down lactose to glucose and galactose
  26. Isomaltase has what effect
    Cleaves alpha-1,6 bonds in isomaltose and dextrins
  27. Why do you get gas when you eat beans
    The undigested portions of the beans are rapidly fermented by colon bacteria
  28. Alpha galactosidase from Aspergillus niger is effective for
    Preventing gas by breaking down what can't be broken down by the intestines (Beano)
  29. What culture has over 90% non-persistent lactase
    Eastern Asians
  30. Zymogens
    Inactive enzyme precusurs that become active when stimulated by another enzyme. This is a feature to protect the active form from damaging the cell that synthesizes it
  31. What are some Zymogens used in the intestines
    • Chymotrypsinogen
    • Pro-Phospholipase A2
    • Trypsinogen
    • Pepsinogen
    • Angiotensinogen
  32. What activates all of the pancreatic Zymogens
  33. Pancreatic lipase is different from many other pancreatic enzymes in that
    It is secreted in its final form, but is only efficient when bound to colipase in the Duodenum
  34. Chylomicrons have what role
    Transport food lipids and cholesterol from the intestine throughout the body
  35. VLDL, IDL, and LDL have what function
    Transport cholesterol form the liver to other tissues (bad cholesterol)
  36. What is the function of HDL
    Transport cholesterol and lipids from tissues to the liver which the liver uses to make bile salts (good cholesterol)
  37. The breakdown of alcohol happens primarily in what organ and organelle
    In the mitochondria in the liver via alcohol dehydrogenase
  38. Metabolism of alcohol produces
    • ATP
    • NADH
    • H+
    • Acetyl-CoA (further converted to triglycerides causing lipidemia and a fatty liver)
  39. What reactions are inhibited by consumption of alcohol
    • Glycolysis
    • Beta oxidation
    • Krebs cycle
    • (All are dependent on NAD+)
    • Gluconeogenesis
  40. Antabuse are Disulfiram drugs that
    • Make alcoholics extremely sensitive to alcohol becoming sick after consuming it.
    • It does this by inhibiting mitochondrial aldehyde dehydrogenase
Card Set
Digestion Enzymes S2M2