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Flashcards in Erythrocyte Biochemistry Deck (40):
1

Human adults have _____ RBCs

We produce _____ RBCs per second

___% of hemoglobin is synthesized before the nucleus is extruded

The remaining ___% is made in the reticulocyte

25 trillion

2.4 million

65%

35%

2

Hemoglobin is a tetramer made of 2 _______ chains and 2 ________ chains

Hemoglobin contains 4 units of _______, which each contain a _______ iron atom, and they carry O2, heme is hydro______

Alpha-globin

Beta-globin

Heme

Ferrous (Fe2+)

Phobic

3

When there is a substitution of valine for glutamic acid at amino acid position #6 in B-globin, we see __________

Sickle cell anemia

4

Sickle cell anemia causes __________ of hemoglobin and ________ shaped RBCs which ____________ (also associated with __________ anemia)

Polymerization

Sickle-shaped

Impede circulation

Hemolytic

5

Hemoglobin in the muscle is called _________

It has a _______ affinity for O2 than Hemoglobin and has a _________ curve

Myoglobin

Higher

Hyperbolic

6

The steepest part of the dissociation curve of hemoglobin and oxygen affinity is from ______ pO2 with the low end corresponding to the onset of _________ and the high end corresponding to the onset of _______

20-40 torr

Exercise

Rest

7

The Oxygen dissociation curve of hemoglobin is shifted to the right by what factors?

Exercise, increased temperature, increased CO2, increased 2,3-BPG and decreased pH

8

What does positive cooperativity mean in regards to hemoglobin?

As one O2 binds to one heme, it facilitates the binding of O2 to another heme. Hb binds to O2 in a cooperative fashion.

9

When the ODC shifts to the right, Hb is giving up _______ to the _________

More O2

Tissues

10

Fetal Hemoglobin has a __________ affinity for O2 than the mother's Hb because ...

The fetal hemoglobin (HbF) curve is to the left or right of the normal Hb curve?

Higher

Because the baby needs to steal the mom's O2 to get any

HbF is to the left

11

Iron readily exchanges _______and is the ideal catalyst for ______-________ reactions taking the dietary form of iron, ________ to a form usable in the blood, ____________.

Ions

Oxidation-reduction

Ferric 3+

Ferrous 2+

12

Because iron cannot freely diffuse across membranes, it involves several proteins. Name four.

Ferrireductase

DMT1 (divalent transporter)

Hephaestin

Ferroportin

13

Fe3+ is reduced to Fe2+ by ________

Dcytb. (Duodenal cytochrome b)

14

fe2+ is transported into the enterocyte by ________ on the apical surface

DMT1

15

Fe2+is transported outside the enterocyte cell into the blood by __________ with also requires _________ to perform the transport (changing Fe2+to Fe3+)

Ferroportin

Hephaestin (a ferroxidase)

16

_________ carries iron to tissues where it is needed, including the bone marrow undergoing erythropoiesis

It binds to iron with a _______ affinity and delivers iron safely in a ________ form.

Transferrin

High

Non-toxic

17

TfR stands for Transferrin Receptor and these mediate ___________

_________ have 800,0000 TfR per cell

In the cell, heme is made in the ___________

__________ is the protein that transports iron out of the endosome

Endocytosis

Erythroblasts

Mitochondria

DMT1

18

Organ disfunction due to iron overload is called ___________and may present as ...

Treatment is _________

Hemochromatosis

Cirrhosis, arthritis, endocrinopathy, skin pigmentation, cardiomyopathy

(Usually manifest in 6th decade)

Treatment is blood-letting

19

A regulator of iron homeostasis that binds to ferroportin and causes internalization of ferroportin and its destruction by proteolysis is called ____________

This peptide is made by the ________

Hepcidin

Liver

20

When iron is high, hepcidin expression ________

And ferroportin levels ________

Increases

Decrease

21

When hepcidin decreases and ferroportin increases, iron must be _______ in the body

Low

22

HFE regulates _________ expression by binding to ________ which turns on ___________ expression

Hepcidin

TfR2

Hepcidin

23

If HFE is mutated, it cannot bind to _______ and there is no control over ________ because ________ wasn't turned on

TfR2

Ferroportin activity

Hepcidin

24

The production of RBCs is dependent on which two vitamins?

Vitamin B12
&
Vitamin B9

25

Vitamin B12 is also known as _________

Vitamin B9 is also known as ________ or __________

Cobalamin

Folate or folic acid

26

Deficiency of vitamin B12 and folate causes ____________ anemia, which occurs as a result of diminished ___________ of __________ in the bone marrow erythroblasts

Megaloblastic

Synthesis

DNA

27

__________ anemias are characterized by large RBCs

What is another sign of this anemia on a slide

Macrocytic

Megaloblastic macrocytic anemia is seen as very large erythroblasts in the bone marrow as well as hypersegmented neutrophils (more than 5 lobes)

28

Folic acid, or pteroylglutamic acid, has 3 parts. Name them.

Pteridine

P-amino-benzocaine acid (PABA)

Chain of glutamate residues

29

Folate can exist as__________ which can be reduced to the active form of ________ by ___________

FH2

THF

Dihydrofolate reductase

30

The function of THF is to _________ ________ units (e.g. _______ groups) from doors to acceptors.

THF plays a vital role in _____ synthesis

Transfer

Carbon

CH3

DNA

31

THF becomes _____________ when the carbon side chain of serine is transferred to it, this is then transferred to ________to form ______ during which DHF is made and is then reduced by _________ to THF to restart the cycle

N5,10-methylene-THF

Deoxyuridylate (dUMP)

Deoxythymidylate (dTMP)

Dihydrofolate reductase

32

Folate is available as an N5-methyl-THF that needs to be ___________ in order to enter the folic acid cycle as THF. _________ is needed in order for this process to happen.

Demethylated

Cobalamin (B12)

33

If B12 is not available,the folate is stuck as ________

N5-methyl-THF

34

Cobalamin transfers the methyl group from N5-methyl-THF to ________ to create _________using the enzyme, ____________

Homocysteine

Methionine

Methionine synthase

35

Because a dietary deficiency of Vitamin B12 is rare, 85% of B12 deficiency is due to the lack of a protein called _______________

Intrinsic factor

36

In B12 absorption, dietary B12 binds to proteins called ________ made by gastric mucosa cells

R-binder proteins

37

Parietal cells of the stomach make ___________ and proteases from the pancreas degrade ________proteins in the duodenum, releasing ______

Then _________ carries B12 to the ileum where receptors bring it to the body

Intrinsic factor (44 kDa protein encoded by gene of Chr 11)

R-binder proteins

B12

Intrinsic factor

38

B12 receptor is _______

Cobalamin circulates through the blood carried by ___________

Cubulin

Transcobalamin

39

Pernicious anemia is a _____________ deficiency due to a lack of ____________ (which is necessary for absorption of the vitamin above)

This is a __________ __________ anemia

B12

Intrinsic factor

Megaloblastic macrocytic anemia

40

In order to determine whether a B12 deficiency is due to a failure of diet or absorption, the ___________ is used

Schilling Test