LEC 4 Flashcards
where is heme synthesized in the cell
mitochondria
how many hemes are in a hb molecule
4
how many ml of o2 can a hb molecule carry
1.34
how many golbin chains are in a hb molecule
4
where is heme located in a hb molecule
crevice fromed by E and F helices
where do heme and golbin bind in the cell
cytoplasm
what protein structure is hb
quarternary structure (globular)
what is the composition of hb
2 alpha and 2 beta chains, 4 hemes, and 4 O2 molecules
what chromosome has the alpha chain gene
16
what chromosome has the beta chain gene
11
incorporation of ____ into protoporphyrin IX by the enzyme _____
Fe 2+; ferrochelatase
what are the types of normal adult hb
hb A, hb a2, and hb f
what type of hb: gower -1, gower-2, portland, and hb F
intrauterine hb
type of hb: hb F and hb A
at birth
type of hb: hb H and bart’s hb
abnormal
hb name: alpha 2 beta 2
adult (A)
hb name: alpha 2 delta 2
adult (A2)
hb name: alpha 2 gamma 2
fetal
hb name: zeta 2 gamma 2
portland
hb name: zeta 2 epsilon 2
gower 1
hb name: alpha 2 epsilon 2
gower 2
hb name: beta 4
hb h
hb name: gamma 4
bart’s
what is the normal Po2
around 27 mm Hg
when the o2 dissociation curve is shifted to the left there is a _____ O2 affinity
higher
when the o2 dissociation curve is shifted to the right there is a _____ O2 affinity
lower
what shift? decreased temp, 2-3 DPG, hydrogen, and CO2
left
what shift? increased temp, 2-3 DPG, and hydrogen
right
def? hb oxygen binding affinity is inversely related both to acidity and to the conc of CO2
bohr effect
in a RBC one HCO3- will be exchanged for one ___ shifted inward
Cl-
what are the sources for heme iron
animal food
what kind of iron has more efficient absorption
heme iron
what are the sources for non-heme iron
veggies
what substances enhance iron absorption
acidic food
what substances inhibit iron absorption
oxalates, phytates, phosphates, and calcium
what enzyme reduces iron so it can enter the intestinal lumen
ferrireductase (Dcytb)
what transporter transports iron through the luminal mmb to the enterocyte cytoplasm
DMT 1
what removes iron from heme
HO-1
what protein transports ferrous iron out of enterocyte and into the blood
ferroportin
what protein reoxidizes iron
hephaestin
protein that inhibits ferroportin from transporting iron out of the enterocyte
hepcidin
what organ detects iron levels
liver
increase iron in blood = ____ in hepcidin
increase
what does hepcidin interact with on cells with iron
ferroportin
once hepcidin and ferroportin bind what happens
iron is prevented from leaving the cell
protein? bind to and carries Fe3+ to the erythropoietic cells, has two binding sites for iron (binds 2 iron atoms), before iron is bound it is called apotransferrin
transferrin
Protein: stores ferric iron
ferritin
once ferric iron binds to ferritin what is it called
ferritin
protein? degraded form of ferritin and metabolically less
available
hemosiderin
what lab test is an indicator of available transport iron
serum iron
what is the reasoning for a fasting serum iron specimen
it will be highest in the morning
what condition has decreased serum iron
iron deficiency anemia
what is an indirect indicator of transferrin level
total iron binding capacity
what lab test is an indicator of iron stores
plasma ferritin
what conditions will have increased plasma ferritin (makes iron storage result not reliable)
acute inflammation/infections
what iron lab test is more reliable
serum iron
serum transferrin receptors will ____ in cases of low serum iron
increase
if protoporphyrin IX does not bind to iron what can it bind to
zinc
