What makes R-Binder proteins?
Gastric mucosa cells in the stomach
Where does nonheme iron come from?
Oxygen Dissociation curve for hemoglubin
The uptake of transferin by cells is done by what process?
Receptor mediated endocytosis via transferin receptor (TfR).
B12 deficiency is often caused by what.
What impact can this deficiency have?
Dietary lack is not often the cause, 3 ug dailly allowance
85% of cases are the lack of a protein called intrinsic factor.
Causes megaloblastic anemia because of the decrease of N5,10-methylene-THF and on DNA synthesis
What is the efficiency of hemoglobin in delivery of oxygen to from lung to tissue.
Drops from 7.4 to 7.2 pH
Describe B12 Absorbtion
B12 binds to R-binder proteins in somach
Degraded by proteases in the dudenom releasing B12
Intrinsic factor carries B12 to ileum where it is absorped by receptors.
In what form foes ferritin store iron?
What converts Fe3+ in non-heme iron to Fe2+
What is the generation of erythrocytes known as?
Where does heme iron come from?
Why is HbF in the fetus higher in affinity the HbA in the mother?
Oxygen travels mother to fetus.
HbF does not bind well to 2,3-BPG so this cannot decrease its affinity as much.
What happens to affininty for oxygen as pH decreases. How does this work and what is this effect called?
O2 affinity decreases as pH decreases
His 146 picks up H+ from tissue and causes a conformational change in Hg.
Called the Bohr Effect
How do internalized endosomes get transferin to the mitchondira for heme synthesis?
Clatherin coated endosome transiently docks and DMT1 helps to facilitate the transport of iron out of the endosome.
2,3-Biphosphoglycerate has what effect on O2?
Reduces the affinity of O2 so Hb gives up more O2 to tissues
What form of folate is dietary?
What is portential therapy for sickle cell anemia?
What are the worries in this?
Changing HbS to HbF using hydroxyurea
This is a toxic chemotherapeutic agent
What cell features are observed in megaloblastic anemia?
Large erythrocytes >100 fL (normal is 80-100) (same ratio of hematocrit)
Hyper-segmented neutrofills (more then 5 lobes, 3-4 normal)
How is B12 transported into and throughout the blood
Intrinsic factor bound to cobalin is taken up by receptor-mediated endocytosis.
Cobalin circulates through the blood by transcobalamin
Stem cells and commited cells of erthropoiesis
What can result as part of Hereditary Hemochromatosis?
Organ dysfunction due to iron overload: cirrhosis, arthritis, endocrinopathy, skin pigmentation, cardiomyopathy
What is the function of THF?
Transfers carbon units from donors to acceptors
Is vital for DNA synthesis
What transports iron in the blood?
What enzyme refuces folate to DHF and THF?
Oxidizes NADPH to NADP
Add 2 electons + hydrogens at a time
Describe folate metabolism.
THF to N5,10-methylene-THF as the carbone side chain of a serine is transfered
Carbon of N5,10-methylene-THF is transfered to deoxyuridylate (dUMP) to form deoxythmidylate (dTMP) during which DHF is made
How does positive cooperativity work?
The binding of O2 to Fe of a globin subunit pulls the proximal F8 histindine down ==> this pulls the globin FG-helix and changes the interaction with the other globin chain in Hb
What converts free iron to Fe3+?
Dysregulation of iron uptake and export by enterocyte
15g of Total iron body weight
What is the disease and treatment?
What is the fetal hemoglubin and when does it peak?
Hb F (a2g2)
Gamma chain peaks right before birth and then subsides.
Alpha continually increases up untill birth where it levels off.
What makes Intrinsic factor?
Pariatal cells in the stomach.