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Flashcards in Iron and Heme Deck (40)
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1
Q

What two molecules can iron be bound to during storage?

A

hemosiderin and ferritin

2
Q

What is the protein that transports iron in the blood?

A

transferrin

3
Q

What part of the GI tract is iron absorbed in?

A

duodenum

4
Q

What enzyme in the GI tract can reduce iron from Fe3+ to Fe2+?

A

Cyt p450

5
Q

What GI protein is responsible for releasing iron into the plasma?

A

Ferroportin

6
Q

Which protein inhibits ferroportin?

A

hepcidin

7
Q

What protein transports iron out of the endosome and into the cell?

A

DMT1

8
Q

What protein does ferritin form when it misfolds and degenerates?

A

hemosiderin

9
Q

At what level is ferritin production regulated?

A

post-transcriptional

10
Q

Do iron regulatory proteins bind to the 5’ UTR of ferritin in the presence of absence of iron?

A

absence

11
Q

What does the presence of iron do to the IRPs?

A

inhibits their inhibition of iron processing

12
Q

What does free iron do to ALA synthase levels?

A

increase

13
Q

What does free iron do to transferrin receptor levels?

A

decreases transferrin receptor levels

14
Q

What percent saturation is transferrin typically?

A

1/3

15
Q

What is the best measure for serum iron stores?

A

serum ferritin

16
Q

Which interleukin stimulates the synthesis of hepcidin?

A

IL-6

17
Q

Absence of what enzyme cause Acute Intermittent Porphyria?

A

PBG Deaminase

18
Q

Absence of what enzyme causes Porphyria Cutanea Tarda?

A

UPG Decarboxylase

19
Q

What two enzymes of heme synthesis does lead inhibit?

A

Ferrochelatase and ALA Dehydratase

20
Q

What organelle is ALA Synthase located? Why?

A

Mitochondria

availability of succinyl-CoA from citric acid cycle

21
Q

What two enzymes of heme synthesis are located in the mitochondria?

A

ALA Synthase

Ferrochelatase

22
Q

What is the main inhibitory molecule of ALA synthase?

A

heme

23
Q

What commonly leads to a porphyria?

A

alcohol consumption

24
Q

What two products accumulate during Acute Intermittent Porphyria?

A

ALA and PBG

25
Q

What is more common, AIP or PCT?

A

PCT

26
Q

How is PCT diagnosed?

A

urine will fluoresce under UV light

27
Q

What substance accumulates during lead poisoning?

A

ALA

28
Q

The iron response element is found on what three proteins?

A

ferritin

ALA synthase

ferritin receptor

29
Q

What protein can reduce iron on the luminal side of enterocytes?

A

Cytochrome B

30
Q

What is the oxidation state of iron bound to transferrin?

A

Fe3+

31
Q

What two locations will iron be stored in during ACD?

A

RES macrophages

enterocytes

32
Q

Hereditary hematochromatosis can be traced back to what gene? increase or decrease?

A

hepcidin

decrease

33
Q

What two products accumulate during AIP?

A

PBG and ALA

34
Q

What does TIBC specifically measure?

A

transferrin saturation

35
Q

Transferrin saturation below what percent points to iron deficiency?

A

15%

36
Q

Is hepcidin expression increased or decreased during hematochromatosis?

A

decreased

37
Q

What does Fe3+ do to heme synthesis?

A

repress

38
Q

What does hemin do to heme synthesis?

A

repress

39
Q

How is AIP diagnosed?

A

dark red urine

40
Q

Durig iron overload, what is the first cell to express hemosiderin?

A

macrophages