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17 Cards in this Set
- Front
- Back
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Adult hemoglobin consists of 4 ______ chains and 4 ______ groups.
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4 Globin (chains) and 4 heme groups.
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Where are globin chains synthesized?
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On polyribosomes in the cytoplasm.
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Where are heme groups synthesized?
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Protoporphoryin is combined with iron in the Mitochondria to form heme, which is then expelled into the cytoplasm to combine with globin chains to form hemoglobin.
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Globin gene clusters are found on which 2 chromosomes?
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Chromosome 16 (2 alpha, 2 pseudogenes, 1 zeta)
Chromosome 11 (1 beta, 1 epsilon, 2 gamma, 1 delta, 1 pseudogene) |
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When do epsilon and zeta chains disappear?
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In the first trimester, as they are only synthesized in the yolk sac.
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What are 3 embryonic hemoglobin types?
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Gower1 (2 zeta, 2 epsilon)
Gower 2 (2 alpha, 2 epsilon) Portland (2 zeta, 2 gamma) |
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What does HbF stand for?
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Fetal Hemoglobin (2 alpha, 2 A-gamma/G-gamma)
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When does the switch from producing HbF to adult hemoglobin occur?
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The switch occurs maily at birth.
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96% of adult hemoglobin is HbA, 4% is HbA2, what is the difference?
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HbA consists of 2 alpha and 2 beta chains.
HbA2 consists of 2 alpha and 2 delta chains. |
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Disorders of heme synthesis due to abnormal accumulation of porphyrin precursors or porphyrins in the bone marrow/liver are known as _________.
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Porphyrias disorders
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Inherited disorders characterized by reduced or absent synthesis of one or more globin chains are known as ____________.
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Thalassemias
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Structural hemoglobinopathies are disorders characterized by synthesis of abnormal globin chains, give the most common example.
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Sickle Cell Anemia (HbS).
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What is the result of imbalanced production of one globin chain?
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Accumulation and precipitaiton of malformed chains leading to membrane damage and hemolysis.
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Which thalassemia is associated with a worse phenotype.
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Beta-Thalassemia (excess alpha chains inflict worse oxidative and structural damage.
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There are 2 Beta globin genes (1 on each chromosome 11). If 1 is mutated, the patient is said to have ________. If both are mutated the patient is said to have ________.
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Beta Thalassemia Trait,
Beta Thalassemia Major |
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There are 4 alpha globin genes (2 on each chromosome 16). What is the outcome if 1,2,3 or all 4 are mutated?
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1: Silent Carrier (asymptomatic)
2: Alpha Thalassemia Trait (mostly asymptomatic) 3: Hb H (thalassemia intermediate symptoms) 4: Hydrops fetalis (lethal) |
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Most phenotypes of Sickle Cell anemia result from what mutaion?
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A single nucleotude mutation (Glu -> Val)
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