MIDTERM - HEMOGLOBIN METABOLISM Flashcards

1
Q

iron bearing protein contained
within the erythrocytes .

A

hemoglobin

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2
Q

one gram of hemoglobin can carry
____ of oxygen

A

1.34 ml

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3
Q

The concentration of hemoglobin within RBCs is approximately ____ and its molecular weight is
approximately ____.

A

34 g/dL; 64,000 Daltons

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4
Q

what are the main function of hemoglobin

A

transport oxygen from lungs to tissue, carbon dioxide from tissue to lungs.

contributes to acid-base balance by binding and releasing hydrogen ions and

transport nitric oxide (a regulator of vascular tone)

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5
Q

a regulator of vascular tone

A

nitric oxide

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6
Q

Hemoglobin is the first protein whose structure was described
using _____.

A

x-ray crystallography

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7
Q

-
-

A

carbon, hydrogen, nitrogen

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8
Q

the ring of heme composed of carbon, hydrogen, and nitrogen is called as

A

protoporphyrin IX

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9
Q

what is the central atom found in the heme of the hemoglobin

A

ferrous iron

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10
Q

When the ferrous irons are oxidized
to the ferric state (Fe3+), they no longer can bind oxygen.

true or false

A

True

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11
Q

Oxidized hemoglobin is also called ___

A

methemoglobin

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12
Q

describe the globin strcture

A

The four globin chains comprising each hemoglobin molecule
consist of two identical pairs of unlike polypeptide chains, 141 to
146 amino acids each.

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13
Q

in globin structure, each globin chain is divided into how many helices and non helices

A

divided into eight helices separated by
seven nonhelical segments

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14
Q

Hemoglobin is a tetramer of four globin chains with a heme attached
to each globin chain.

true or false

A

true

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15
Q

globin chain alpha and its number of amino acids

A

141

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16
Q

globin chain beta and its number of amino acids

A

146

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17
Q

aside from globin chain alpha, what is the globin chain that has 141 amino acids as well?

A

globin chain zeta

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18
Q

how many amino acids do theta has?

A

unknown

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19
Q

the hemoglobin molecule can be describe as its

A

primary
secondary
tertiary
quaternary structures

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20
Q

the structure of hemoglobin that refers to the amino acid sequence of the POLYPEPTIDE CHAINS

A

primary structure

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21
Q

the structure of hemoglobin that refers to chain arrangements in HELICES and NON HELICES

A

secondary structure

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22
Q

the structure of hemoglobin that refers to the
arrangement of the helices into a PRETZEL LIKE CONFIGURATION

A

tertiary hemoglobin

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23
Q

The quaternary structure of hemoglobin, also called a _____, describes the complete hemoglobin molecule

A

tetramer

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24
Q

The complete hemoglobin molecule is SPHERICAL, has four heme groups
attached to four polypeptide chains, and may carry up to
four molecules of oxygen

true or false

A

true

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25
Q

A small percentage of Hb A is ____.

A

glycated

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26
Q

is a posttranslational modification formed by the nonenzymatic
binding of various sugars to globin chain amino groups over
the life span of the RBC

A

glycation

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27
Q

Heme biosynthesis occurs in the ____of bone marrow erythroid precursors,

A

mitochondria and cytoplasm

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28
Q

can mature rbc make hemoglobin?

A

nope, they will lose the capability to make as they lose mitochondria and ribosomes along the maturation process

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29
Q

how many enzymes do we have for heme synthesis

A

8

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30
Q

how many enzymes involve in hemem synthesis in both mitochondria and cytoplasm

A

each have 4 enzymes involve

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31
Q

the heme synthesis starts with the condensation of what substances

A

succinyl-coA and glycine

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32
Q

glycine and succinyl coenzyme A (CoA) is catalyzed by ___ to produced aminolevulinic acid (ALA)

A

aminolevulinate synthase

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33
Q

aminolevulinic acid (ALA)

–> in the cytoplasm, aminolevulinic acid dehydratase converts ALA to ___

A

porphobilinogen (PBG)

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34
Q

porphobilinogen (PBG)

–> it will then be converted into ______ through the enzyme ____

A

hydroxymethylbilane; hydroxymethylbilane synthase (PBG deaminase)

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35
Q

uroporphyrinogen III

–>will be converted into ____ through what enzyme

A

coproporphyrinogen III ; uroporphyrinogen III decarboxylase

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35
Q

hydroxymethylbilane

–> it will be converted into ___ through enzyme ____

A

uroporphyrinogen III; uroporphyrinogen III synthase

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35
Q

what are the products made along the heme synthesis under cytosol or cytoplasm?

A

porphobilinogen
hydroxymethylbilane
uroporphyrinogen III
coproporphyrinogen III

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35
Q

From coproporphyrinogen III, it will go back to mitochondria to continue and be converted into

A

protoporphyrinogen III

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36
Q

coproporphyrinogen III will be converted into protoporphyrinogen III through what enzyme

A

coproporphyrinogen III oxidase

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36
Q

protoporphyrinogen III will be converted into ___ by the enzyme ____

A

protoporphyrin IX ; protoporphyrin III oxidase

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37
Q

protoporphyrin IX will form a heme through what enzyme

A

ferrochelatase

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38
Q

where does the heme synthesis starts and ended?

A

mitochondria

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39
Q

in globin synthesis, which chromosome do alpha and zeta globin are coded?

A

short arm chromosome 16

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40
Q

in globin synthesis, which chromosome do epsilon, gamma, delta and beta globin gene cluster are coded?

A

short arm of chromosome 11

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41
Q

expect for which globin chain we do have a single genome per chromatid. In this 2 globin chain, they both have 2 copies per chromatid

A

alpha and gamma globins

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42
Q

Production of globin chains takes place in erythroid precursors from the PRONORMOBLAST through the circulating POLYCHROMATIC ERYTHROCYTES, but not in ____.

A

mature erythrocytes

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43
Q

Transcription of the globin genes to messenger ribonucleic acid (mRNA) occurs in the ___,

A

nucleus

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44
Q

Transcription of the globin genes to messenger ribonucleic acid (mRNA) occurs in the nucleus,

and translation of mRNA to the globin polypeptide chain occurs on ___

A

Ribosomes in the cytoplasm.

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45
Q

which globin chain produces more mRNA upon transcription? is it the alpha globin or the beta globin

A

alpha globin, but less efficient in translation

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46
Q

alpha globin makes more MRNA but the globin gene chain is much more efficient in translating,

Therefore, a and b chains are produced in
approximately _____ amounts. After translation is complete,
chains are released from the ribosomes in the cytoplasm.

A

equal

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47
Q

the alpha chain has what charge?

A

positive charge

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48
Q

b chain has what charge?

A

negative

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49
Q

arrange the highest affinity of a chain starting alpha

A

alpha chain
gamma chain
delta chain

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50
Q

in order to form a complete hemoglobin mob\lecule

Two heterodimers then combine
to form a ____.

A

tetramer

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51
Q

The two alpha and two beta chain will form ____ the major hemoglobin present from 6 months of age through adult hood

A

HB A

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52
Q

chains comprising the HB A2

A

Two alpha and two delta

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53
Q

Hb A2 comprises less
than ___ of total hemoglobin in adults.

A

3.5%

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54
Q

Hb F contains ___ chains.

A

two alpha and two gamma

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55
Q

These RBCs with Hb F are
called F or ___

A

A/F cells.

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56
Q

A third function of
hemoglobin involves the
___, ___- and ____ of nitric oxide.

A

binding, inactivation, and
transport

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57
Q

Nitric oxide is secreted by
___

A

vascular endothelial cells

58
Q

Nitric oxide is secreted by
vascular endothelial cells
and causes ___

A

relaxation of
vascular wall smooth
muscle and vasodilation

59
Q

The function of hemoglobin
is to readily bind oxygen
molecules in the lung,
which requires ____ oxygen
affinity; to transport
oxygen;

A

high

60
Q

hemoglobin transport and efficiently
unload oxygen to the
tissues, which requires ___oxygen affinity

A

low

61
Q

is the ability of hemoglobin to bind or
release oxygen

A

oxygen affinity

62
Q

The relationship between OXYGEN tension and HEMOGLOBIN SATURATION with oxygen is described as

A

Oxygen dissociation curve

63
Q

it states the relationship of oxygen affinity with hemoglobin to PH

A

bohr effect

64
Q

In Bohr effect, if the pH increase or the blood is alkaline (alkalosis) the affinity of hemoglobin to oxygen will

(increase. decrease)

A

increase affinity

65
Q

In Bohr effect, if the pH decrease or the blood is acidic (acidosis) the affinity of hemoglobin to oxygen will

(increase. decrease)

A

decrease affinity

66
Q

increase temperature

A

shift to the right

67
Q

decrease temperature

A

shift to the left

68
Q

increase organic phosphate (2,3 DPG)

A

shift to the right

69
Q

decrease organic phosphate (2,3 DPG)

A

shift to the left

70
Q

increase p(CO2)

A

shift to the right

71
Q

decrease p(CO2)

A

shift to the left

72
Q

increase p(CO)

A

shift to the left

73
Q

decrease p(CO)

A

shift to the right

74
Q

increase pH

A

shift to the left

75
Q

decrease pH

A

shift to the right

76
Q

The normal position of curve depends on

A

§ Concentration of 2,3-DPG
§ H+ ion concentration (pH)
§ CO2 in red blood cells
§ Structure of Hb

77
Q

HbS will shft to ??

A

shift to the right

78
Q

HbF will shift to the

A

shift to the left

79
Q

what are the physiological forms of hemoglobin

A

oxyhemoglobin
Deoxyhemoglobin

80
Q

hemoglobin in combination WITH
oxygen gives pinkness to the skin and mucous membrane.
seen in arterial circulation

A

oxyhemoglobin

81
Q

hgb with iron but no O2, seen in
venous circulation. Unassociated with oxygen

A

deoxyhemoglobin

82
Q

a hemoglobin that is Found in normal human embryos
and fetuses with a gestational age
of less than three months

A

Embryonic Hemoglobin

83
Q

this hemoglobin is absent at birth

A

Embryonic Hemoglobin

84
Q

what are the hemoglobin under embryonic hemoglobin

A

gower I, gower II, and portland

85
Q

in hemoglobin Gower I, what are the globin chains involved

A

2 zeta 2 epsilon

86
Q

what are the globin chains involved in Gower II

A

2 alpha and 2 epsilon

87
Q

what are the globin chains involved in portland

A

2 zeta and 2 gamma

88
Q

the major hemoglobin of the fetus
and newborns

A

fetal hemoglobin

89
Q

fetal hemoglobin is composed of what globin chains

A

2 alpha and 2 gamma

90
Q

when was the fetal hemoglobin produced?

A

4 months after conception

91
Q

normal ADULT hemoglobin

A

hemoglobin A or A1

92
Q

how many percent of hemoglobin in a normal adult does HbA produced after one year onwards

A

95 - 97%

93
Q

Hemoglobin A or A1 is composed of what globin chains?

A

2 alpha 2 beta (141, 146)

94
Q

How many percent do Hemoglobin A2 constitute in the total hemoglobin?

A

less than 3%

95
Q

Hemoglobin A has the globin chains of

A

2 alpha 2 delta

96
Q

a normal hemoglobin that is a product of a degradation of HbA2

A

Hemoglobin 3

97
Q

Hemoglobin 3 has what globin chains?

A

2 alpha 2 delta - same with HbA2 as it’s own degradation

98
Q

This is the primary hemoglobin
in people with sickle cell disease

A

Hemoglobin S

99
Q

what is wrong in terms of the globin chains of blood with sickle cell disease?

A

2 normal alpha
2 abnormal beta

100
Q

causes the red blood cell to deform and
assume a sickle shape when exposed to
decreased amounts of oxygen.

A

Hemoglobin S

101
Q

In hemoglobin S, the Glutamic acid in the 6th position of beta chain place was been replaced by ____

A

Valine

102
Q

In an abnormal hemoglobin, ____ patient with this kind of hemoglobin only has one copy of Beta chain

A

Hemoglobin C

103
Q

In hemoglobin C, instead of glutamic acid , ___ is in B6

A

lysine

104
Q

It usually causes a minor amount of hemolytic
anemia and a mild to moderate
enlargement of the spleen

A

hemoglobin C

105
Q

is one of the most common beta
chain hemoglobin variants in the world.

A

Hemoglobin E

106
Q

People who are homozygous for Hb E (have two
copies of βE) generally have a ____

A

mild hemolytic
anemia, microcytic red blood cells, and a mild
enlargement of the spleen.

107
Q

an abnormal hemoglobin that occurs in some cases of
alpha thalassemia .

A

hemoglobin H

108
Q

hemoglobin has what globin chains

A

4 beta and is response to a sever shortage of alpha chains

109
Q

this kind of hemoglobin gene does not
cause symptoms unless it is combined with another
mutation, such as the one for beta thalassemia
trait

A

true

110
Q

Are acquired hemoglobin variants whose structure has
been modified by drugs or environmental chemicals.

A

CHEMICALLY MODIFIED
HEMOGLOBINS

111
Q

inability to transport oxygen to the tissue well resulting in

A

cyanosis

112
Q

3 types of chemically modified hemoglobins

A

methemoglobin
sulfhemoglobin
carboxyhemoglobin

113
Q
  • Is a form hgb in its ferric state
A

methemoglobin

114
Q

Has a brownish to bluish color and does not revert to
red on exposure to oxygen

A

methemoglobin

115
Q

methemoglobin is Peak in the range of ___ nm at pH ____ under
spectral absorption test.

A

620 – 640; 7.1

116
Q

what are the causes of methemoglobin

A
  • Presence of oxidants-
    -Genetic deficiency
    – decrease activity of MethHB
117
Q

Formed by the irreversible oxidation of Hb of certain drugs and
chemicals.

A

SULFHEMOGLOBIN

118
Q

examples of SULFHEMOGLOBIN

A

a. sulfonomides
b. phenacetin
c. acetanilide

119
Q

In sulfhemoglobin, what is added on the hemoglobin and the resulting color?

A

hydrogen sulfide; greenish color

120
Q

If sulfhemoglobin reaches the critical level in the blood it
imparts the color

A

MAUVE LAVENDER

121
Q

how sulfhemoglobin is reported?

A
  1. Px under prolonged treatment with sulfonamides or aromatic compounds (phenacitin, acetanilide )
    * 2. Px with severe constipation
    * 3. In cases of bacteremia caused by Clostridium perfringens
    * 4. In condition known as enterogenous cyanosis
122
Q

Results from the binding of carbon monoxide to heme iron

A

CARBOXYHEMOGLOBIN

123
Q

Hb can combine with carbon monoxide with affinity ____times greater than that of Oxygen.

A

200

124
Q

___ is termed as silent killer for its colorless gas , odor and patient becomes easily hypoxic.

A

Carbon monoxide

125
Q

methods to detect or determine hemoglobin

A

visual methods
gasometric method
spectronic method
automated
other method such as alkaline, specific gravity, comparator

126
Q

qualitative screening test based on
specific gravity. The density of the
drop of blood is directly proportional to
the amount of hemoglobin it contains.

A

copper sulfate specific gravty

127
Q

what are the visual metjod to determine hgb

A

A. Sahli Method
B .Dares Method
c. Hadens Method
D.Wintrobe
E.Haldene
F.Tallquists

128
Q

The principle of the test is that when
the drop of donor’s blood dropped into
copper sulfate solution becomes
encased in a sac of
copper proteinate, which prevents any
change in the specific gravity for
about 15 seconds.

A

copper sulfate specific gravity

129
Q

Hb will combine and liberate a fixed quantity of O₂.

A

Gasometric Method (Oxygen Capacity
Method)

130
Q

In Gasometric Method (Oxygen Capacity
Method), the blood will be hemolyzed using ___ and the gas is collected and measured in a van slyke apparatus

A

saponin

131
Q

a colorimetric methods under visiual

A

direct matching
acid hematin
alkaline hematin

132
Q

a colorimetric methods under photoelectric

A

1.Oxyhemoglobin Method-
2. Cyanmethemoglobin or HiCN
method

133
Q

a colorimetric - photoeelectric method that measures plasma hemoglobin

A

oxyhemoglobin method

134
Q

a colorimetric - photoeelectric method that is a -standard and reference method use
to measure hemoglobin

A

cyanmethemoglobin or HiCN method

135
Q

what are the factors that can affect hemoglobin results

A

age
sex
altitude of the locality

136
Q

reagents used in cyanmet

A

Modified drabkin’s reagent

137
Q

modified drabkin’s reagent color and pH

A
  • pale and yellow with a pH of 7.2 +
    0.2
138
Q

composition of modified drabkin’s reagent

A

Sodium bicarbonate
1 gram

Potassium cyanide
52 mg

Potassium ferricyanide
198 mg

Distilled water
1000 mL

139
Q

(HYPERCHROMIA)increased hemoglobin level
found in:

A

a. polycythemia
b. dehydration
c. changing from high to low altitudes

140
Q

(oligochromia) decreased hemoglobin
level
found in:

A

anemia

141
Q

Drabkin’s reagent is sensitive to
light

to correct it

A

Store in a brown bottle or in a
dark place

142
Q
  1. WBC Count (>20 x 10 ⁹/L)
    Platelet Count (>700 x 10⁹/L)- can cause turbidity and
    a falsely high
    result

to correct it

A

Centrifuge the solution and
measure the supernatant

143
Q

Lipemic sample can interfere
and can give a false result

to correct it

A

Add 0.01 mL of the patient’s
plasma to 5 mL of drabkin’s
reagent and used the solution as
reagent blank

144
Q

Hb S and Hb C maybe resistant
to hemolysis causing turbidity

to correct it

A

Dilution with distilled water (1:2)

145
Q

. Abnormal globulins found in
multiple myeloma or
Waldenstrom macroglobulinemia
may precipitate

to correct it

A

Add 0.1 g of potassium
carbonate to drabkin’s reagent

146
Q

The hemoglobin determination test is used to

A
  1. Screen for disease associated with anemia
  2. Determine the severity of anemia
  3. Follow the response to treatment for anemia
  4. Evaluate polycythemia