Iron

Question 1

what forms of iron are stable in the body

Answer 1

1. oxidized ferric

2. reduced ferrous

Question 2

where and by what is iron absorbed

Answer 2

basolateral membrane by ferroportin

Question 3

heme remains absorbed across the brush boarder by

Answer 3

heme carrier protein 1

Question 4

heme is hydrolyzed by enzyme _____ into ____ and ______

Answer 4

heme oxygenase
ferrous iron
protoporphyrin

Question 5

nonheme iron hydrolyzed from food by ____ and ___ (released as ferric iron)

Answer 5

proteases

HCL

Question 6

what is found at the brush border to reduce oxidized ferric to reduced ferrous

Answer 6

duodenal cytochrome b reductase

Question 7

what transports iron, calcium, zinc, and copper throughout the cell

Answer 7

mobilferrin

Question 8

what membrane transport protein does the basolateral boarder use

Answer 8

ferroportin (FPN1)

Question 9

ferrous iron transported through basolateral boarder by copper containing protein called

Answer 9

hephaestin

Question 10

what is the glycoprotein made in the liver that carries 2 iron atoms called

Answer 10

transferrin

Question 11

what is the body’s iron storage protein called

Answer 11

ferritin

Question 12

what are the two isoforms of tranferrin receptors

Answer 12

1. TfR1 - cell membranes

2. TfR2 - liver and intestinal cell membranes

Question 13

what are the 3 routes macrophages can acquire iron

Answer 13

1. phagocytosis of RBC’s
2. receptor mediated endocytosis of hemoglobin
3. receptor mediated endocytosis of transferrin

Question 14

what is the primary storage from of iron

Answer 14

ferritin

Question 15

long term storage protein (thought to be degradation product of ferritin)

Answer 15

hemosiderin

Question 16

ferritin levels in the liver drive production of ____ (suppresses iron absorption)

Answer 16

hepcidin

Question 17

fully saturated with 4 iron molecules when cellular iron concentrations are high

Answer 17

iron response element binding protein (IRE-BP)

Question 18

iron response element binding protein (IRE-BP) binds to what cytosolic enzyme

Answer 18

aconitase

Question 19

mitochondrial enzyme involved in last step of heme synthesis

Answer 19

ferrochelatase

Question 20

____ for serotonin synthesis

Answer 20

tryptophan hydroxylase

Question 21

____ for tyrosine synthesis

Answer 21

phenylalanine hydroxylase

Question 22

_____ for dopamine synthesis

Answer 22

tyrosine hydroxylase

Question 23

what two dioxygenases does collagen synthesis require

Answer 23

1. prolyl hydroxylase

2. lysyl hydroxylase

Question 24

what two dioxygenases does carnitine synthesis require

Answer 24

1. trimethyllysine dioxygenase

2. 4 - butyrobetaine dioxygenase

Question 25

iron as a pro-oxidant

Answer 25

fenton reaction

Question 26

_____ enhances iron absorption

Answer 26

vitamin c

Question 27

copper is a cofactor for what two ferroxidase ezymes

Answer 27

1. hephaestin

2. ceruloplasmin

Question 28

iron cannot be mobilized out of small intestine without ___ bc it would lead to ___

Answer 28

copper

anemia

Question 29

__ can cause anemia

Answer 29

lead

Question 30

_____ can insert lead instead of iron into center of heme ring

Answer 30

ferrochelatase (inhibits aminolevulinic acid dehydrase)

Question 31

UL is

Answer 31

45mg/day