B12 and Iron Metabolism S1M2

  1. Why is free iron in the blood dangerous
    It creates free radicals
  2. What is the role of Ferritin
    It is a storage place for iron in the cell, it also protects the cell from iron's potentially harmful effects
  3. What is the role of Transferrin
    It transports iron groups to their destination, carries two at a time
  4. What is the difference between Ferrous iron and Ferric iron
    • Ferrous iron is in the reduced form Fe +2 (II)
    • Ferric iron is in the oxidized form Fe +3 (III)
  5. What is the nutritional requirement of iron per day
    1-3 mg per day
  6. What is the primary way to lose iron
    • Stool
    • For women menstrual loss
  7. When there is a reduced amount of myoglobin and hemoglobin function in the body, how does it respond
    Erythropoeitin is triggered to rev up, which requires Fe II and Heme
  8. Cytochrome P450 has what function that requires the use of iron
    It detoxifies drugs and other oxidative reactions in the ER
  9. Cytochromes a, b, and c use iron in what important function
    ATP production in the mitochondria specifically with the electron transport chain
  10. What do iron response elements do (IRE)
    • They sense iron content in cells and adjust the amount of cellular uptake accordingly.
    • They are found as nucleotides in transferrin and ferritin related mRNA transcripts
  11. What is the protein that controls the movement of iron out of the cell
  12. What is the main site for uptake of iron
  13. What important elements facilitate the uptake of iron into the Duodenum
    • Ascorbic acid
    • Vitamin C
  14. What can inhibit the uptake of iron
    • Phytates
    • Phosphates
    • Tannins
    • Antacids
  15. Hepcidin has what effect on iron
    It is considered the master iron inhibitor and restricts the availability of iron in cancer and inflammation by controlling ferroportin activity
  16. ROS (Reactive oxygen species) promote
    Aging and disease
  17. Iron can be an effective marker for homeostasis of what organ
    • Bone marrow
    • This is because the amount of Ferritin that leaks out of the bone marrow is directly proportional to the iron content
  18. Patient on dialysis need to have iron monitored daily as to ensure
    That the iron is being adequately cleared avoiding iron toxicity
  19. What is inherited hemochromatosis
    It is an inherited iron overload that up regulates the movement of iron into the enterocytes
  20. What are the ages that hemochromatosis is most likely found
    40-60 years old
  21. What are some iron overload disorders
    • Thalassemias (Reduced hemoglobin synthesis)
    • Sideroblastic Anemia (RBC synthesis issues)
    • Chronic liver disease
  22. What does an overload of iron cause
    • Arthropathy (Joint issues)
    • Hepatomegaly
    • Splenomegaly
    • Liver Cirrhosis
    • Hypogonadism
    • Diabetes
    • Skin Hyperpigmentation
  23. What are some treatments for iron overload
    • Phlebotomy 1-2 times a week
    • Avoidance of iron intake
  24. B12 and Folate (Folic Acid) are important to what biological functions
    • DNA synthesis reactions
    • Essential Coenzymes
  25. What is Megaloblastic anemia caused by
    Inhibition of DNA synthesis in RBC's
  26. Cobalamine is an important structural component of
    B12 and is important to nucleotide synthesis, as well as the control of fatty acid synthesis in myelin sheaths
  27. The absorption of B12 in the illeum requires what
    • R-factor
    • Intrinsic Factor
  28. Folate is absorbed by
    Brush border enterocytes
  29. What is Folate absorption inhibited by
    • Phenytoin
    • Alcohol
    • Oral Contraceptives
  30. What will a lack of B12 display that a lack of Folate won't
    Wobbling Gait
  31. In addition to B12 and Folate, what else relating to iron is necessary for erythropoeisis
    Heme biosynthesis
  32. Lead inhibits what important reaction to make heme
    Ferrochelatase (converts protoporphyrin IX into heme by adding the iron element)
  33. Heme is synthesized by what cells
  34. Heme is broken down to what substance by the spleen
  35. What does the interruption to bilirubin clearance cause
  36. Neonatal jaundice can be attributed most of the time to
    Undeveloped liver
  37. While in the blood, what is bilirubin linked to
    Albumin, upon transfer to the liver they disassociate
  38. The eventual elimination of heme is through the
  39. Severe excess of bilirubin in the blood will accumulate in what tissues leading to Kernicterus
    In the nervous tissue, this is very dangerous for infants (passes the BBB)
  40. Ribose is crucial for making substances for the cell to
  41. A deficiency in G6PD can have what effect on Ribose development
    It will inhibit it, leading to an anemic crisis
  42. NADPH has what effect on G6PD
    High amounts inhibits it, because it is its product
  43. Vegetarians are notorious for having low
  44. Pernicious anemia can be due to a lack of
    Intrinsic factor (inability to absorb B12)
  45. If megaloblasts are present in a patient with hematocrit issues what can be eliminated as a cause
    Iron deficiency
  46. Heinz bodies and denatured hemoglobin suggests what what deficiency
  47. Absence of NADPH formation is a positive test for
    Glucose 6 Phosphate dehydrogenase deficiency
  48. Erythrocyte Oxidant control is via
    Glutathione reductase
  49. Steroid and and fatty acid synthesis in the liver is done by
    Fatty acid synthase and HMG-CoA reductase
  50. Aconitase is
    An iron response element (IRE)
  51. What physical property of bilirubin results in jaundice when bilirubin is found in high amounts
    Its fat solubility and hydrophobicity
  52. Homocysteine is converted to cysteine via
    B vitamins
  53. The only two recognizable cobalamine dependent enzymes in human cells are
    • Methylmalonyl CoA mutase
    • Methyltetrahydrofolate- homocysteine methyl transferase (methionine synthase)
  54. Methyltetrahydrofolate- homocysteine methyl transferase (methionine synthase) deficiency leads to
    Megaloblastic anemia
  55. Prophyrias is
    Impaired biosynthesis of Heme
Card Set
B12 and Iron Metabolism S1M2