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1.31: Iron, Bilirubin, Porphyrin

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    38611
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    FOR QUESTIONS 1 - 3 use the following KEY:

    1. formation of amino levulinic acid (ALA) by ALA synthase
    2. conversion of ALA to porphobilinogen (PB) by ALA dehydratase
    3. conversion of PB to Uroporphyrin I
    4. conversion of PB to Uroporphyrin III
    5. conversion of coproporphyrin to protoporphyrinogen IX
    1. Normally the feed—back inhibition by Heme operates at which one of the above steps?:
    2. In acute intermittent porphyria this rate-limiting step is defective:
    3. This step is severely inhibited by lead:

    Use the following Key to answer Questions 4-9:

    1. 1, 2, and 3 are correct
    2. 1 and 3 are correct
    3. 2 and 4 are correct
    4. only 4 is correct
    5. all are correct
    1. Most of the iron in the body is found in:
      1. hemoglobin
      2. haptoglobin
      3. ferritin
      4. peroxides
    2. The transport protein(s) of iron is/are:
      1. ferritin
      2. haptoglobin
      3. hemosiderin
      4. transferrin
    3. The total iron binding capacity (TIBC) calculated from:
      1. transferrin
      2. ferritin
      3. serum iron
      4. hemosiderin
    4. Heme is degraded to form the following compounds:
      1. a linear tetraphrrole
      2. biliverdin
      3. bilirubin
      4. protoporphyrin
    5. Bilirubin is bound by which of the following compound(s)?
      1. bile acids
      2. haptoglobin
      3. hemoglobin
      4. albumin
    6. Heme synthesis is an integral part of which of the following body systems?
      1. respiratory
      2. bone marrow
      3. genitourinary
      4. hepatic
    7. Delta bilirubin is:
      1. free, unconjugated bilirubin
      2. unconjugated bilirubin, covalently bound to albumin
      3. bilirubin monoglucuronide
      4. conjugated bilirubin that does not react in direct reaction
      5. none of the above
    8. Measurement of urinary urobilinogen is:
      1. useful in detection of renal disease
      2. useful in detection of inborn errors of heme synthesis
      3. useful in detection of liver disease
      4. useful for screening for porphobilinogens
      5. not particularly useful for any of the above
    Answer
    1. a (p. 664)
    2. d (p. 665-667)
    3. b (p. 669)
    4. b (p. 659)
    5. d (p. 660)
    6. b (p. 661-662)
    7. a (p. 671)
    8. d (p. 671)
    9. c (p. 664)
    10. b (p. 671)
    11. e (p. 673)

    1.31: Iron, Bilirubin, Porphyrin is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts.

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