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HEMATOLOGY 1 > Lesson 6: Hemoglobin > Flashcards

Lesson 6: Hemoglobin Flashcards

1
Q

True or False:
Polypeptide chains are manufactured on ribosomes.

A

True

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2
Q

True or False:
Globin chains are assembled from two pairs of polypeptide chains.

A

True

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3
Q

True or False:
Does globin chain synthesis has four primary chains that can be produced?

A

True

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4
Q

What is Hb forms?

A

An embryonic form, α2, ε2, is detected early in fetal life.

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5
Q

What are the Hemoglobin F structure?

A
  • four heme groups
  • globin chains 2 alpha and 2 gamma chain
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6
Q

Hb forms
What happened by 3 months of embryonic life?

A

Embryonic Hb is replaced by fetal Hb (Hb F).

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7
Q

Hb forms
After birth, the production of Hb F slowly ceases

A

6 months: <8% of the total Hb content
(a) 1 year, infants <2% Hb F
(b) Less than 1% Hb F is normally found in adults

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8
Q

What is Adult hemoglobin (HbA)?

A

The major adult form, consisting of two α chains and two β chains (i.e., α2β2),

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9
Q

Hemoglobin A2 (HbA2) has?

A

1.5% to 3.5%

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10
Q

α-chains has?

A

chromosome 16

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11
Q

all other globin chains has?

A

chromosome 11

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12
Q

What is the main of an RBC?

A

contain, transport, and protect hemoglobin molecules.

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13
Q

Each globin chain consists of?

A

Four globin chains (most commonly, α2β2) and four heme groups, each with a center iron molecule.

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14
Q

True or False:
Does ferric form cannot bind oxygen?

A

True

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15
Q

What are the three kinds of hemoglobin allosteric effects?

A
  • Bohr effect
  • 2,3 Biphosphoglycerate (BPG)
  • Carbon monoxide
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16
Q

What are the function of hemoglobin?

A

a. Cooperative binding of oxygen

a. 1 facilitates the further binding of oxygen
a. 2 oxygen dissociation curve

17
Q

What is the Oxygen-hemoglobin dissociation?

A

Exercise

18
Q

The factors that shift curve to right are:

A

Increase ph (more acidc)
Increase temperature
Increase PCO2
Increase 2,3 - PBG

19
Q

What is Bohr effect?

A
  1. enhance the release
    of oxygen
  2. carbonic anhydrase
20
Q

Chemical reaction of Bohr effect

A

CA
Metabolically active tissue → CO2 + H2O → HCO− 3 + H+

21
Q

Lungs chemical reaction under Bohr effect

A

CA
HCO− 3 + H+ → CO2 + H2O

22
Q

What is the third allosteric affect demonstrated by Hb?

A

Regulation of the oxygen affinity of Hb by 2,3-diphosphoglycerate (2,3-DPG).

23
Q

Hemoglobin can exist in?

A

two allosteric forms

24
Q

What is T form?

A

low oxygen affinity state of hemoglobin

25
Q

The allosteric properties of HB arise from what?

A

interactions between the α and β chains

26
Q

The T form is stabilized by:

A

(i) Binding of 2,3-DPG
(ii) Binding of CO2
(iii) Binding of H+

27
Q

What is R (i.e., reactive) form?

A

refers to the high oxygen affinity state, in which the iron in each heme ring is readily accessible to oxygen binding.

28
Q

What is oxygen transport?

A
  1. Regulation
  2. In a normal steady state
    Oxygen is carried in the blood in two forms
    Each gram of Hb has the maximum capacity to bind 1.34 mL of oxygen.
  3. Carbon monoxide binds 210 times stronger than oxygen to a hemoglobin molecule.
29
Q

Carbon dioxide transport

A

Approximately 5% of the total CO2 in arterial blood is physically dissolved in plasma.

30
Q

What is Carboxyhemoglobin (HbCO)?

A

A carbon monoxide (CO) variant of Hb found in the blood at levels <1% of the total Hb in a normal individual.

31
Q

Laboratory diagnosis

A

(1) A blood level of 0.5% is typical in nonsmokers.
(2) Blood levels of up to 5% are typical of chronic smokers.
(3) Assays
(a) Screening methods use a mixture of a patient hemolysate and 1 Mol/L NAOH.
(b) Quantitative methods - gas chromatography and spectrophotometry

32
Q

What is sulfhemoglobin?

A

An Hb variant resulting from the oxidative degeneration of Hb by the addition of a sulfur atom to each Hb molecule.

33
Q

Laboratory diagnosis of sulfhemoglobin

A

Analysis of a sample hemolysate for a increase in an absorption band at 620 nm.

34
Q

What is methemoglobin?

A

(HbM) is Hb with the heme-iron in the ferric (Fe3+) valance.

35
Q

Laboratory diagnosis of methemoglobin:

A

(1) Heinz bodies - crystal violet staining.
(2) Diaphorase screening tests
(3) Quantitation with spectrophotometry.
(a) HbM levels above 1.5%
(b) KCN

36
Q

What is glycosylated hemoglobin?

A

(HbA1) is a minor component of adult Hb on chromatography analysis.

HEMATOLOGY 1 (3 decks)

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