MIDTERM - HEMOGLOBIN METABOLISM Flashcards
(150 cards)
1
Q
iron bearing protein contained
within the erythrocytes .
A
hemoglobin
2
Q
one gram of hemoglobin can carry
____ of oxygen
A
1.34 ml
3
Q
The concentration of hemoglobin within RBCs is approximately ____ and its molecular weight is
approximately ____.
A
34 g/dL; 64,000 Daltons
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)
5
Q
a regulator of vascular tone
A
nitric oxide
6
Q
Hemoglobin is the first protein whose structure was described
using _____.
A
x-ray crystallography
7
Q
-
-
A
carbon, hydrogen, nitrogen
8
Q
the ring of heme composed of carbon, hydrogen, and nitrogen is called as
A
protoporphyrin IX
9
Q
what is the central atom found in the heme of the hemoglobin
A
ferrous iron
10
Q
When the ferrous irons are oxidized
to the ferric state (Fe3+), they no longer can bind oxygen.
true or false
A
True
11
Q
Oxidized hemoglobin is also called ___
A
methemoglobin
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.
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
14
Q
Hemoglobin is a tetramer of four globin chains with a heme attached
to each globin chain.
true or false
A
true
15
Q
globin chain alpha and its number of amino acids
A
141
16
Q
globin chain beta and its number of amino acids
A
146
17
Q
aside from globin chain alpha, what is the globin chain that has 141 amino acids as well?
A
globin chain zeta
18
Q
how many amino acids do theta has?
A
unknown
19
Q
the hemoglobin molecule can be describe as its
A
primary
secondary
tertiary
quaternary structures
20
Q
the structure of hemoglobin that refers to the amino acid sequence of the POLYPEPTIDE CHAINS
A
primary structure
21
Q
the structure of hemoglobin that refers to chain arrangements in HELICES and NON HELICES
A
secondary structure
22
Q
the structure of hemoglobin that refers to the
arrangement of the helices into a PRETZEL LIKE CONFIGURATION
A
tertiary hemoglobin
23
Q
The quaternary structure of hemoglobin, also called a _____, describes the complete hemoglobin molecule
A
tetramer
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
25
A small percentage of Hb A is ____.
glycated
26
is a posttranslational modification formed by the nonenzymatic
binding of various sugars to globin chain amino groups over
the life span of the RBC
glycation
27
Heme biosynthesis occurs in the ____of bone marrow erythroid precursors,
mitochondria and cytoplasm
28
can mature rbc make hemoglobin?
nope, they will lose the capability to make as they lose mitochondria and ribosomes along the maturation process
29
how many enzymes do we have for heme synthesis
8
30
how many enzymes involve in hemem synthesis in both mitochondria and cytoplasm
each have 4 enzymes involve
31
the heme synthesis starts with the condensation of what substances
succinyl-coA and glycine
32
glycine and succinyl coenzyme A (CoA) is catalyzed by ___ to produced aminolevulinic acid (ALA)
aminolevulinate synthase
33
aminolevulinic acid (ALA)
--> in the cytoplasm, aminolevulinic acid dehydratase converts ALA to ___
porphobilinogen (PBG)
34
porphobilinogen (PBG)
--> it will then be converted into ______ through the enzyme ____
hydroxymethylbilane; hydroxymethylbilane synthase (PBG deaminase)
35
uroporphyrinogen III
-->will be converted into ____ through what enzyme
coproporphyrinogen III ; uroporphyrinogen III decarboxylase
35
hydroxymethylbilane
--> it will be converted into ___ through enzyme ____
uroporphyrinogen III; uroporphyrinogen III synthase
35
what are the products made along the heme synthesis under cytosol or cytoplasm?
porphobilinogen
hydroxymethylbilane
uroporphyrinogen III
coproporphyrinogen III
35
From coproporphyrinogen III, it will go back to mitochondria to continue and be converted into
protoporphyrinogen III
36
coproporphyrinogen III will be converted into protoporphyrinogen III through what enzyme
coproporphyrinogen III oxidase
36
protoporphyrinogen III will be converted into ___ by the enzyme ____
protoporphyrin IX ; protoporphyrin III oxidase
37
protoporphyrin IX will form a heme through what enzyme
ferrochelatase
38
where does the heme synthesis starts and ended?
mitochondria
39
in globin synthesis, which chromosome do alpha and zeta globin are coded?
short arm chromosome 16
40
in globin synthesis, which chromosome do epsilon, gamma, delta and beta globin gene cluster are coded?
short arm of chromosome 11
41
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
alpha and gamma globins
42
Production of globin chains takes place in erythroid precursors from the PRONORMOBLAST through the circulating POLYCHROMATIC ERYTHROCYTES, but not in ____.
mature erythrocytes
43
Transcription of the globin genes to messenger ribonucleic acid (mRNA) occurs in the ___,
nucleus
44
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 ___
Ribosomes in the cytoplasm.
45
which globin chain produces more mRNA upon transcription? is it the alpha globin or the beta globin
alpha globin, but less efficient in translation
46
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.
equal
47
the alpha chain has what charge?
positive charge
48
b chain has what charge?
negative
49
arrange the highest affinity of a chain starting alpha
alpha chain
gamma chain
delta chain
50
in order to form a complete hemoglobin mob\lecule
Two heterodimers then combine
to form a ____.
tetramer
51
The two alpha and two beta chain will form ____ the major hemoglobin present from 6 months of age through adult hood
HB A
52
chains comprising the HB A2
Two alpha and two delta
53
Hb A2 comprises less
than ___ of total hemoglobin in adults.
3.5%
54
Hb F contains ___ chains.
two alpha and two gamma
55
These RBCs with Hb F are
called F or ___
A/F cells.
56
A third function of
hemoglobin involves the
___, ___- and ____ of nitric oxide.
binding, inactivation, and
transport
57
Nitric oxide is secreted by
___
vascular endothelial cells
58
Nitric oxide is secreted by
vascular endothelial cells
and causes ___
relaxation of
vascular wall smooth
muscle and vasodilation
59
The function of hemoglobin
is to readily bind oxygen
molecules in the lung,
which requires ____ oxygen
affinity; to transport
oxygen;
high
60
hemoglobin transport and efficiently
unload oxygen to the
tissues, which requires ___oxygen affinity
low
61
is the ability of hemoglobin to bind or
release oxygen
oxygen affinity
62
The relationship between OXYGEN tension and HEMOGLOBIN SATURATION with oxygen is described as
Oxygen dissociation curve
63
it states the relationship of oxygen affinity with hemoglobin to PH
bohr effect
64
In Bohr effect, if the pH increase or the blood is alkaline (alkalosis) the affinity of hemoglobin to oxygen will
(increase. decrease)
increase affinity
65
In Bohr effect, if the pH decrease or the blood is acidic (acidosis) the affinity of hemoglobin to oxygen will
(increase. decrease)
decrease affinity
66
increase temperature
shift to the right
67
decrease temperature
shift to the left
68
increase organic phosphate (2,3 DPG)
shift to the right
69
decrease organic phosphate (2,3 DPG)
shift to the left
70
increase p(CO2)
shift to the right
71
decrease p(CO2)
shift to the left
72
increase p(CO)
shift to the left
73
decrease p(CO)
shift to the right
74
increase pH
shift to the left
75
decrease pH
shift to the right
76
The normal position of curve depends on
§ Concentration of 2,3-DPG
§ H+ ion concentration (pH)
§ CO2 in red blood cells
§ Structure of Hb
77
HbS will shft to ??
shift to the right
78
HbF will shift to the
shift to the left
79
what are the physiological forms of hemoglobin
oxyhemoglobin
Deoxyhemoglobin
80
hemoglobin in combination WITH
oxygen gives pinkness to the skin and mucous membrane.
seen in arterial circulation
oxyhemoglobin
81
hgb with iron but no O2, seen in
venous circulation. Unassociated with oxygen
deoxyhemoglobin
82
a hemoglobin that is Found in normal human embryos
and fetuses with a gestational age
of less than three months
Embryonic Hemoglobin
83
this hemoglobin is absent at birth
Embryonic Hemoglobin
84
what are the hemoglobin under embryonic hemoglobin
gower I, gower II, and portland
85
in hemoglobin Gower I, what are the globin chains involved
2 zeta 2 epsilon
86
what are the globin chains involved in Gower II
2 alpha and 2 epsilon
87
what are the globin chains involved in portland
2 zeta and 2 gamma
88
the major hemoglobin of the fetus
and newborns
fetal hemoglobin
89
fetal hemoglobin is composed of what globin chains
2 alpha and 2 gamma
90
when was the fetal hemoglobin produced?
4 months after conception
91
normal ADULT hemoglobin
hemoglobin A or A1
92
how many percent of hemoglobin in a normal adult does HbA produced after one year onwards
95 - 97%
93
Hemoglobin A or A1 is composed of what globin chains?
2 alpha 2 beta (141, 146)
94
How many percent do Hemoglobin A2 constitute in the total hemoglobin?
less than 3%
95
Hemoglobin A has the globin chains of
2 alpha 2 delta
96
a normal hemoglobin that is a product of a degradation of HbA2
Hemoglobin 3
97
Hemoglobin 3 has what globin chains?
2 alpha 2 delta - same with HbA2 as it's own degradation
98
This is the primary hemoglobin
in people with sickle cell disease
Hemoglobin S
99
what is wrong in terms of the globin chains of blood with sickle cell disease?
2 normal alpha
2 abnormal beta
100
causes the red blood cell to deform and
assume a sickle shape when exposed to
decreased amounts of oxygen.
Hemoglobin S
101
In hemoglobin S, the Glutamic acid in the 6th position of beta chain place was been replaced by ____
Valine
102
In an abnormal hemoglobin, ____ patient with this kind of hemoglobin only has one copy of Beta chain
Hemoglobin C
103
In hemoglobin C, instead of glutamic acid , ___ is in B6
lysine
104
It usually causes a minor amount of hemolytic
anemia and a mild to moderate
enlargement of the spleen
hemoglobin C
105
is one of the most common beta
chain hemoglobin variants in the world.
Hemoglobin E
106
People who are homozygous for Hb E (have two
copies of βE) generally have a ____
mild hemolytic
anemia, microcytic red blood cells, and a mild
enlargement of the spleen.
107
an abnormal hemoglobin that occurs in some cases of
alpha thalassemia .
hemoglobin H
108
hemoglobin has what globin chains
4 beta and is response to a sever shortage of alpha chains
109
this kind of hemoglobin gene does not
cause symptoms unless it is combined with another
mutation, such as the one for beta thalassemia
trait
true
110
Are acquired hemoglobin variants whose structure has
been modified by drugs or environmental chemicals.
CHEMICALLY MODIFIED
HEMOGLOBINS
111
inability to transport oxygen to the tissue well resulting in
cyanosis
112
3 types of chemically modified hemoglobins
methemoglobin
sulfhemoglobin
carboxyhemoglobin
113
* Is a form hgb in its ferric state
methemoglobin
114
Has a brownish to bluish color and does not revert to
red on exposure to oxygen
methemoglobin
115
methemoglobin is Peak in the range of ___ nm at pH ____ under
spectral absorption test.
620 – 640; 7.1
116
what are the causes of methemoglobin
- Presence of oxidants-
-Genetic deficiency
– decrease activity of MethHB
117
Formed by the irreversible oxidation of Hb of certain drugs and
chemicals.
SULFHEMOGLOBIN
118
examples of SULFHEMOGLOBIN
a. sulfonomides
b. phenacetin
c. acetanilide
119
In sulfhemoglobin, what is added on the hemoglobin and the resulting color?
hydrogen sulfide; greenish color
120
If sulfhemoglobin reaches the critical level in the blood it
imparts the color
MAUVE LAVENDER
121
how sulfhemoglobin is reported?
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
Results from the binding of carbon monoxide to heme iron
CARBOXYHEMOGLOBIN
123
Hb can combine with carbon monoxide with affinity ____times greater than that of Oxygen.
200
124
___ is termed as silent killer for its colorless gas , odor and patient becomes easily hypoxic.
Carbon monoxide
125
methods to detect or determine hemoglobin
visual methods
gasometric method
spectronic method
automated
other method such as alkaline, specific gravity, comparator
126
qualitative screening test based on
specific gravity. The density of the
drop of blood is directly proportional to
the amount of hemoglobin it contains.
copper sulfate specific gravty
127
what are the visual metjod to determine hgb
A. Sahli Method
B .Dares Method
c. Hadens Method
D.Wintrobe
E.Haldene
F.Tallquists
128
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.
copper sulfate specific gravity
129
Hb will combine and liberate a fixed quantity of O₂.
Gasometric Method (Oxygen Capacity
Method)
130
In Gasometric Method (Oxygen Capacity
Method), the blood will be hemolyzed using ___ and the gas is collected and measured in a van slyke apparatus
saponin
131
a colorimetric methods under visiual
direct matching
acid hematin
alkaline hematin
132
a colorimetric methods under photoelectric
1.Oxyhemoglobin Method-
2. Cyanmethemoglobin or HiCN
method
133
a colorimetric - photoeelectric method that measures plasma hemoglobin
oxyhemoglobin method
134
a colorimetric - photoeelectric method that is a -standard and reference method use
to measure hemoglobin
cyanmethemoglobin or HiCN method
135
what are the factors that can affect hemoglobin results
age
sex
altitude of the locality
136
reagents used in cyanmet
Modified drabkin’s reagent
137
modified drabkin's reagent color and pH
- pale and yellow with a pH of 7.2 +
0.2
138
composition of modified drabkin's reagent
Sodium bicarbonate
1 gram
Potassium cyanide
52 mg
Potassium ferricyanide
198 mg
Distilled water
1000 mL
139
(HYPERCHROMIA)increased hemoglobin level
found in:
a. polycythemia
b. dehydration
c. changing from high to low altitudes
140
(oligochromia) decreased hemoglobin
level
found in:
anemia
141
Drabkin’s reagent is sensitive to
light
to correct it
Store in a brown bottle or in a
dark place
142
2. WBC Count (>20 x 10 ⁹/L)
Platelet Count (>700 x 10⁹/L)- can cause turbidity and
a falsely high
result
to correct it
Centrifuge the solution and
measure the supernatant
143
Lipemic sample can interfere
and can give a false result
to correct it
Add 0.01 mL of the patient’s
plasma to 5 mL of drabkin’s
reagent and used the solution as
reagent blank
144
Hb S and Hb C maybe resistant
to hemolysis causing turbidity
to correct it
Dilution with distilled water (1:2)
145
. Abnormal globulins found in
multiple myeloma or
Waldenstrom macroglobulinemia
may precipitate
to correct it
Add 0.1 g of potassium
carbonate to drabkin’s reagent
146
The hemoglobin determination test is used to
1. Screen for disease associated with anemia
2. Determine the severity of anemia
3. Follow the response to treatment for anemia
4. Evaluate polycythemia
