HEMOGLOBIN Flashcards
found in the rbc of the body
hemoglobin
each rbc contains approximately ____ hemoglobin molecules
280 million hemoglobin molecules
main function of rbc
transport of oxygen from the lungs to the body’s cell
rbc contains a protein called
hemoglobin
carries oxygen
hemoglobin
hemoglobin molecule is composed of a protein group, known as
globin
hemoglobin have __ heme groups, associated with an iron atom.
4 heme groups
1 heme = ___ of oxygen and 1 hemoglobin molecule = ____ of oxygen
1 mole of oxygen ; 4 moles of oxygen
in synthesis of hb molecule, the heme portion begins..
Heme Portion: begins in the mitochondria with the formation of D-ALA from glycine and succinyl coenzyme A
in synthesis of hb molecule, the globin portion begins..
Globin portion: produced on specific ribosome in the cytoplasm of the red blood cells
The globin in each hemoglobin molecule consists of ___ polypeptide chains which
determine the type of hemoglobin formed.
four
Gene involved for Alpha & Zeta chains:
chromosome 16
Gene involved for Beta, Delta, Epsilon & Gamma chains:
chromosome 11
hb in Adult
HbA1 > 95%
HbA2 1.5-3%
HbF <2%
hb in neonate
-HbF 60-80%
-HbA 20-40%
This is the designation for the normal hemoglobin that exists after birth. Hemoglobin __ is a tetramer with two alpha chains and two beta chains (a2b2).
Hemoglobin A
This is a minor component of the hemoglobin found in red cells after birth and consists of two alpha chains and two delta chains (a2d2).
Hemoglobin A2
Hemoglobin F is the predominant hemoglobin during fetal development. The molecule is a tetramer of two alpha chains and two
gamma chains (a2g2).
Hemoglobin F.
This the predominant hemoglobin in people with sickle cell disease. The alpha chain is normal.
Hemoglobin S
in hemoglobin S, Valine replaces
GLUTAMIC ACID at 6th position
results from a mutation in the beta globin
gene and is the predominant hemoglobin found in people with hemoglobin __ disease (a2bC2).
Hemoglobin C.
relatively benign, producing a mild hemolytic
anemia and splenomegaly.
Hemoglobin C.
in hemoglobin c , lysine replaces
GLUTAMIC ACID at 6th position
People with this disease have a mild hemolytic anemia and mild splenomegaly. this trait is benign and is extremely common in S.E. Asia and in some areas equals hemoglobin A in frequency.
Hemoglobin E
in Hemoglobin E, lysine replaces
GLUTAMIC ACID at 26th position
a variant in which a mutation in the alpha globin gene produces an alpha globin chain that is
abnormally long.
Hemoglobin Constant Spring.
The quantity of hemoglobin in the cells for hemoglobin CS is low for two reasons.
First, the messenger
RNA for hemoglobin Constant Spring is unstable. Some is degraded prior to
protein synthesis. Second, the Constant Spring alpha chain protein is itself unstable.
result of hemoglobin constant spring
The result is a thalassemic phenotype. From family of ethnic Chinese background
from the Constant Spring district of Jamaica
a tetramer composed of four beta globin
chains and forms in people with three-gene alpha thalassemia as well as in people with
the combination of two-gene deletion alpha thalassemia and hemoglobin
Constant Spring.
Hemoglobin H
Hemoglobin Barts develops in fetuses with four-gene deletion alpha thalassemia.
During normal embryonic development, the episilon gene of the alpha globin gene locus
combines with genes from the beta globin locus to form functional hemoglobin molecules.
The episilon gene turns off at about 12 weeks, and normally the alpha gene takes over. With
four-gene deletion alpha thalassemia no alpha chain is produced.
Hemoglobin Barts
hemoglobin barts was named
From St. Bartholomew’s Hospital in London. The hospital has the fond sobriquet,
St. Barts, and the hemoglobin was named “hemoglobin Barts.”
Hemoglobin is made of two subunits derived from genes in the alpha gene
cluster on chromosome 16 and two subunits derived from genes in the beta
gene cluster on chromosome 11.
Compound Heterozygous Conditions
Having two different variant genes from the alpha globin gene cluster or two
different variant genes from the beta globin gene cluster (a gene for
hemoglobin S and one for hemoglobin C)
Compound Heterozygous Conditions
Patients with hemoglobin SC disease inherit a gene for hemoglobin S from one parent, and a gene for hemoglobin C from the other. Hemoglobin C interacts with hemoglobin S to produce some of the abnormalities seen in patients with sickle cell disease. On average, patients with hemoglobin ____disease have milder symptoms than do those with sickle cell disease.
Hemoglobin SC disease
In this condition, the patient has inherited a gene for hemoglobin S from one parent and a gene for beta-thalassemia from the other. Has large quantity of normal hemoglobin produced by the beta-thalassemia gene. (Thalassemia genes produce normal hemoglobin, but in variably reduced amounts).
Sickle/beta-thalassemia
The combination of hemoglobin E and beta-thalassemia produces a
condition more severe than is seen with either hemoglobin E trait or
beta-thalassemia trait.
moderately severe thalassemia (thalassemia intermedia)
most common in people of S.E. Asian background.
Hemoglobin E/beta-thalassemia
Has alpha globin gene cluster
The alpha globin gene cluster on one of the two chromosomes 16 has
both alpha globin genes deleted. On the other chromosome 16, the
alpha1 gene has the Constant Spring mutation.
produces a severe shortage of alpha globin chains.
The excess beta chains associate into tetramers to form hemoglobin H.
Alpha thalassemia/Hemoglobin Constant Spring.