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15 Cards in this Set

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Which is absorbed better: Fe +2 or +3?
Fe +2
In the gut, what helps dissociate Fe from its carrier?
Low pH of gut
In the gut, Fe +3 is reduced to Fe +2 by?
ascorbic acid (vitamin C)
Free Fe is toxid and therefore it must be carried by?
Chelated-Fe
Hemosiderin
Hemosiderin-Fe +3
long term storage
Gotten rid of via sloughing of mucosal cells
Ferritin
Short term storage
Ferritin-Fe+3
Takes Fe to blood
How does Fe get into cell?
Transferrin-Fe+3 binds to a TfR ---> endocytosed--->vesicle
Is transferrin recycled?
Yes, transferrin/TfR is brought to surface, and transferrin is released into blood
Once Fe+3 gets into the cell, does it stay +3?
No, it is reduced to Fe +2
iron response element (ire)
nucleotides on mRNA of TfR and ferritin
iron responsive factor (irf)
protein that binds to IRE when Fe is low
When there is low Fe, what happens to the translation of TfR?
1. IRF is not bound by Fe
2. IRF bound to IRE on 3'
3. Ribonuclease blocked and mRNA preserved leaving to more translation of TfR
When there is low Fe, what happens to the translation for ferritin?
1. IRF is not bound by Fe
2. IRF bound to IRE on 5'
3. Ribosome blocked and cannot make more ferritin.
When there is high Fe, what happens to the translation of TfR?
1. Fe bound to IRF
2. Ribonuclease can destroy mRNA
3. No TfR made
When there is high Fe, what happnes to the translation of Ferritin?
1. Fe bound to IRF
2. Ribosome can make mRNA
4. More Ferritin made