HEMA Hgb Flashcards
HEMOGLOBIN
Structure
B. Biosynthesis
C. Regulation
D. Functions
E. Derivatives
iron bearing protein contained
within the ___ .
it is synthesized by young
___ from the ____ up to _____.
____ can carry ___
Hemoglobin
-erythrocytes
-erythroblast
- polychromatophilic normoblast
stage
- reticulocytes stage
- one gram of hemoglobin
- 1.34 ml of oxygen
1 heme= ___
1 hgb= ____
1mole of O
4 moles of 0
FUNCTIONS OF
HEMOGLOBIN
Transport oxygen from the lungs
to the tissue and carbon dioxide
from the tissue.
Acid – base balance regulation
ph7.35-7.45
Hemoglobin assist in maintaining the pH of blood by _____, ___ and ___ of ___ ( a regular vascular tone that refers to degree of constriction which blood vessel experience)
binding, releasing and transport of nitric oxide
Structure of Heme
Composition of Heme
- Protophorphyrin IX
Consists of a ring of :
Carbon ( C)
Hydrogen ( H)
Nitrogen
2.Ferrous iron (Fe2+)
The______ comprising each hemoglobin molecule
consist of _____ , 141 to
146 amino acids each.
Each globin ___ separated by ___
Globin Structure
- four globin chains
-two identical pairs of unlike polypeptide chains
- 8 helices
-7 non helices segment
Alpha
Beta
Gamma A
Gamma G
Delta
Epsilon
Zelta
Theta
Number of amino acids (important in each globin chain- * if not = problem esp. he,oglobinopathies)
141 (if Adult Hgb 141+ 141 alpha= 282 no more/less)
146
146 (position 136: alanine)
146 (position 136:glycine)
146
146
141
Unknown
COMPLETE HEMOGLOBIN
MOLECULE
* The hemoglobin molecule can be described by its
1.
2.
3.
4.
COMPLETE HEMOGLOBIN
MOLECULE
1.primary, ——– amino acid sequence
2 Secondary —— helices and non
helices (pleated sheet)
3. Tertiary ——- pretzel like
configuration
4. quaternary ——- complete molecule
Enzyme involved in Heme synthesis
ALA synthase (Aminolevulinic synthase)
ALA dehydralase
Hydroxymethylbilane synthase (PBG deaminase)
Uroporphyrinogen III synthase
Uroporphyrinogen III decarboxylase
Coproporphyrinogen-III oxidase
Protoporphyrinogen III oxidase
Ferrochelatase
Flow of Heme synthesis
First step: Condensation- It takes place in mitochondria of Succinyl coA with Glycine w/c catalyzes by ALA synthase to form Amino levulinic acid. This ALA will go out from mitochondria which will go into cytoplasm, by the help of ALA dehydralase which will have multiple transformation/ reaction starting from Porphobilinogen-> hydroxymethylbilane which is catalyzed by Hydroxymethylbilane synthase (PBG deaminase). Then forming uroporphyrinogen III by the help of Uroporphyrinogen III synthase. Then will form COP3 (Coproporphyrinogen III) which will catalyzes by Uroporphyrinogen III decarboxylase, then it will go back to mitochondria to form Protoporphyrinogen III by the COP3 oxidase and eventually form Protoporphyrin IX by Protoporphyrinogen III oxidase.
Last step: In mitochondria, Insertion of Iron w/c will catalyzes by Ferrochelataseto form Heme.
Always be ____ because if oxidize to ___ they can no longer bind to ___
- the oxidize hgb called ___ which can’t carry oxygen
Ferrous Iron (Fe2+)
Ferric
Oxygen
Methemoglobin
Occurs in the cytoplasm of __ and
____.
* Polypepdtide chains are manufactured in the ___.
* ____ are made via transcription
of genetic code to mRNA and
translation of mRNA
SYNTHESIS OF GLOBIN
normoblast
reticulocytes
ribosomes
Globin protein
ONTOGENY OF GLOBIN SYNTHESIS
Time Region
Type of Globin Gene
Type of Hb
1. 3 weeks of Gestation
2. 5 weeks of Gestation
3. 6-30 weeks of Gestation
4. 30 weeks of Gestation
5. At Birth
Yolk Sac
zeta and epsilon
Hb Gower1
Yolk Sac
γ&α
Hb Portland
Hb Gower II
Liver & spleen
α & γ & β
Hb F
Liver
delta
Hb A2
Bone marrow
___
HbA
Hemoglobin Function
Oxygen Transport
Carbon dioxide transport
Nitric Oxide transport
The function of hemoglobin is to readily bind oxygen molecules in the ___, which requires ____; ____; and_____, which requires low
oxygen affinity.
Oxygen Transport
lung
high oxygen affinity
to transport oxygen
to efficiently unload oxygen to the
tissues
A second crucial function of
hemoglobin
Carbon dioxide transport
third function of
hemoglobin involves the
___, ___ and ____. It is secreted by
vascular endothelial cells and causes relaxation of vascular wall smooth muscle and vasodilation .
Nitric Oxide transport
- binding, inactivation, and
transport of nitric oxide
is the ability of hemoglobin to bind or release oxygen . Expressed in terms of the ___ at which hgb is 50% saturated
- The relationship between ____ and ____ is described as ODC
- _____ relationship of O2 affinity with Hb to pH which states that :
Inc pH ( alkalosis) = ______
Dec pH ( acidosis )= _____
OXYGEN DISSOCIATION CURVE
- Oxygen Affinity
- oxygen tension
- O2 tension(partial tension) and hemoglobin saturation with oxygen
-Bohr Effect
- Inc Hb affinity for O2
- dec hb affinity for O2
FACTORS THAT INFLUENCE OXYGEN BINDING
Shift to the left Shift to the right
Temperature
Organic phosphates (2,3 DPG) 2,3-diphosphoglyceric acid
p(CO₂) partial pressure of carbon dioxide
p(CO)
pH
Decrease
Increase
Decrease
Increase
Decrease
Increase
Increase
Decrease
Increase
Decrease
HB-OXYGEN DISSOCIATION CURVE (Sigmoid curve)
the normal position of curve depends on __, ___, ____, ____
Concentration of 2,3-DPG
H+ ion concentration (pH)
CO2 in red blood cells
Structure of Hb