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Respiratory > Norm fxn- Biochemistry > Flashcards

Norm fxn- Biochemistry Flashcards

1
Q

True or False: Mb has a higher affinity for O2 than Hb.

A

True

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2
Q

True or false: Hb is made of 2 different pairs of subunits put together.

A

False. They’re identical subunits.

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3
Q

How many alpha and beta subuntis are there in Hb?

A

2 alpha

2 beta

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4
Q

Which state of Fe can accept the O2 in the middle of the Hb? (Fe++ or Fe+++)

A

Ferrous state (Fe++)

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5
Q

True or False: when 1 O2 binds to a Hb subunit, it facilitates the binding of subsequent O2’s to the same Hb.

A

True

big point here

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6
Q

How much stronger does CO bind to Hb than O2?

A

200x stronger (essentially irreversible)

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7
Q

This is the type of Hb in 98% of adults, and is composed of a2b2

A

HbA

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8
Q

This is the type of Hb in 2% of adults where the subunit structure is a2d2

A

HbA2

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9
Q

This is the type of Hb where the subunit structure is a2g2, and is the trpincipal form of Hb from ~7mo before birth unity ~1mo after birth.

A

HbF

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10
Q

True or False: HbF has a slightly lower O2 affinity than HbA.

A

False. It’s higher to ensure O2 delivery from mom’s blood to fetal blood.

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11
Q

Since most CO2 is transported as HCO3 in the blood, what is the role of the Hb?

A

Hb binds the H+ forming HHb

Bohr effect

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12
Q

Does the affinity of Hb for O2 increase or decrease with an increase in pH?

A

Increase

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13
Q

Since Hb can bind to H+ ions and O2 ions, what is it’s role in the blood for regulation?

A

Buffer

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14
Q

True or False- 2,3-DPG is a toxin that should never be present as it lowers the affinity for Hb binding to O2.

A

False- it’s a normal glycolysis product and is vital for regualting binding of O2 to Hb

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15
Q

Does DPG bind to the oxygenated or deoxygenated form of Hb?

A

Deoxygenated

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16
Q

How many DPG molecules bind to 1 Hb?

A

1

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17
Q

When Hb is oxygenated, the central cavity becomes smaller, and what happens to DPG?

A

It’s expelled

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18
Q

True or False: DPG binds HbF less strongly, giving a higher affinity of HbF for O2 than HbA.

A

True

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19
Q

What replaces Glu at position 6 in the B-chain to cause sickle cell (HbS)?

A

Val

20
Q

In which state (deoxy or oxy) does the HbS become sticky by transforming the RBC into the sickle-cell shape?

A

Deoxygenated

21
Q

Do homozygous or heterozygous individuals get sickle-cell anemia?

A

Homozygous (it’s recessive)

22
Q

What is the incidence of SCA in african americans?

A

~1/500

23
Q

True or False: heterozygous sickle cell individuals are always asymptomatic.

A

False. they get symptomatic at high altitudes

24
Q

Heterozygous individuals are at an advantage when there is a prevalence of what?

A

Malaria

25
Q

What are the 2 ways of Dx SCA?

A
  1. blood smear

2. protein electrophoresis

26
Q

In HbC, what replaces the Glu on position 6 of the B-chain?

A

Lys

27
Q

When HbC crystalizes, what is the common pathology?

A

viscous blood and mild hemolysis

28
Q

Is HbC milder or more severe than HbS?

A

Milder

29
Q

True or False: metHb is a daily occurance where it’s made and then reduced back to normal Hb.

A

True

30
Q

What is the enzyme to reduce metHb to Hb?

A

NADH-dependent methemoglobin reductase

31
Q

What is the condition where there is a deficiciency in the reductase or HbM?

A

Methemoglobinemia

32
Q

HbM favors which state of Fe?

A

Fe+++

33
Q

HbM can only exist in which state, heterozygous or homozygous? Why?

A

Heterozygous because homozygous is incompatible with life.

34
Q

What is the biggest Sx for methemoglobinemic patients?

A

Cyanosis

35
Q

This is a group of disorders where the synthesis of either Hb chain is reduced or absent.

A

Thalassemias

36
Q

What types of mutations typically cause a-Thalassemias?

A

deletions

37
Q

What types of mutations typically cause B-Thalassemias?

A

point mutations

38
Q

Which thalassemia is always fatal (a or B)?

A

alpha

39
Q

This is the group of disorders where the a-globin is reduced or absent.

A

a-thalassemia

40
Q

How many a-genes are missing in a-thalassemia 1?

A

1

41
Q

Is a-thalassemia 1 symptomless?

A

yes

42
Q

Mild anemia is present with a-thalassemia 2 because of how many a-genes missing?

A

2

43
Q

3 missing a-genes can cause which disease which causes moderately severe hemolytic anemia?

A

HbH disease

44
Q

4 missing a-genes (like we talked about before) is fatal and shows up with what condition as a fetus?

A

Hydrops fetalis

45
Q

This is the increased concentrations of red cells, usually from hemoglobinopathies which favor the oxyHb state.

A

Polycythemia

46
Q

Since the oxyHb is so strong in polycythemias, what happens to peripheral tissues?

A

Hypoxia from inadequate O2 supply

47
Q

This is a useful index for diabetes because of the glycosylated Hb.

A

HbA1c

Respiratory (9 decks)

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