Test2week2materialThursday3lectures Flashcards
Without vitamin ___, you can’t create heme so you then become anemic
B6 (pyridoxine)
What causes sickle cell anemia (It occurs on the beta gene)?
An amino acid change of Glutamic acid (A polar “-“ molecule) to Valine (non-polar) on the beta chain of Hemoglobin (HbA->HbS)
Does increasing or decreasing these Hemaglobin effects lower the affinity to bind oxygen?
1) H+
2) BPG
3) Co2
1) Increasing (since protons promote O2 dissociation)
2) Increase
3) Increase
What kind of hemoglobin is found in children and what subunits comprise it? Also, since it is found in children and gives them a higher affinity for O2 than the mothers Hb, why does this occur?
HbF (2 Alpha and 2 Gamma chains)
Because fetal hemoglobin does not bind to BPG (so it increases its affinity for oxygen)
What is iron stored in and where is this normally kept (organ wise?)
Ferritin and in the liver (however, there is some leakage of ferritin into the blood serum so it can be a great tool to measure iron deficiencies)
Iron transport in enterocytes (intestinal cells) occurs in various steps. Steps:
1) Iron must be reduced to the __ +
2) Taken up by DMT1
3) Transferred to the basolateral side (opposite side) and pushed out through ___ in the presence of a hephaestin and under control of ___
4) Finally, Fe2+ is converted back to Fe3+ by hephaestin and is then taken up in the blood and carried back to bone marrow by ___ for erythropoiesis
2+
ferroportin
Hepcidin (controls ferroportin by destroying it)
Transferrin
Hemochromatosis means what? Also what kind of hereditary does it have and what mutation causes it? Finally, what does this mutated gene regulate?
Iron overload
Autosomal recessive
Mutations in the HFE gene
Hepcidin expression
Iron deficiency results in __chromic and __cytic cells with __ serum ferritin
Vitamin B12 and Folic acid deficiency results in __chromic and ___cytic cells
- Hypo, Micro, Low (Hypo, Normo, or Macro - Chromic is referring to iron levels which turns the cell’s color different)
- Normo, Macro
Megaloblastic anemia (Macrocytic-hypochromic) can result from deficiencies from \_\_ and \_\_\_. How does this deficiency affect the RBCs to cause anemia?
Vitamin B12 (Cobalamin) or Folate (folic acid) (but remember, it's a B12 deficiency that causes a folate deficiency because it can't be converted from methyl to methylene). It diminishes the synthesis of DNA
When you take folate in your diet, it is quickly metabolized to the __ form, and kept in this form (stored) ready for action, but will only be converted in the presence of ___. Folate is finally converted to ___, which can then act as a one-carbon donor so DNA can be synthesized
methyl, vitamin B12, methylene
Vitamin B12 is taken up from the stomach into blood by ___. Which part of the stomach does this occur?
Intrinsic factors, ileum
Explain a schilling test
Used to look for vitamin B12 deficiencies and determine if it’s from a diet deficiency or an absorption deficiency. You saturate someones B12 receptors with a high dose of B12, and then you give them radioactively labeled B12. You collect the urine, and if you see the radioactive B12 in the urine, you know it’s a diet deficiency because it was absorbed perfectly fine. However, if you don’t see the radioactive B12 then it must be an absorption problem (since it never got absorbed and this is most likely from an intrinsic factor aka pernicious anemia).
Iron is at the 2+ state, keylated by the nitrogen rings and the porphyrin ring structure. Also, it involves the proximal and distal histidines. The __ F8 histidine is keylated directly to the iron and that facilitates the conformational changes that occur during oxygenation. Oxygen comes on the side where the ___ E7 histidine exists.
Proximal, Distal
Defects in heme synthesis leads to ___
Porphyrias
What type of porphyrias is characterized by neurological symptoms?
What about a porphyrias that manifests in the skin leading to photosensitivity problems?
Acute Hepatic, Erythropoietic
