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38 Cards in this Set
- Front
- Back
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What are the hemoglobins of normal HbA?
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Two alpha
Two beta |
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What is the normal hemoglobin component of the minor (2%) in adults?
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two alpha
two delta |
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What is the hemoglobin chains of fetal hemoglobin?
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two alpha
two gamma |
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What is the normal protein chains of embryonic hemoglobin(Hb Gower I)?
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Two Zeta
Two Epsilon |
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About what time does HbA become the majority of a human's hemoglobin?
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6th week
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Where are the two alpha genes located (on which chromosome)?
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Chromosome 16
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Where is the beta hemoglobin gene located?
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Chromosome 11
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Define: hemoglobinopathies where the amount of Hb synthesized is low.
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Thalassemias
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Define: A hemoglobinopathy where the synthesis of alpha chains is lower than normal.
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Alpha thalassemia
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Define: A hemoglobinopathy where the synthesis of the beta chain is low.
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Beta thalassemia
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Name one other hemoglobinopathy other than thalassemia.
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Sickle cell anemia
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Name the clinical states and genotypes of alpha-thalassemia.
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Normal (a2-a1)/(a2-a1)
Silent carrier has 3 functional alpha genes HbH 1 functional alpha gene Hb Barts (hydrops fetalis) no functional alpha gene |
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Which is more severe: Loss of alpha2 gene activity or alpha1?
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Alpha 2 gene loss is more sever becomes it is expressed at about 3 times the level of alpha 1.
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What is the normal protein chains of embryonic hemoglobin(Hb Gower I)?
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Two Zeta
Two Epsilon |
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If both alpha globin genes on the same chromosomes are affected (a2thal-a1thal) the mutations are said to be _______.
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"in cis"
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What is the difference between a silent carrier and a non-silent carrier?
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1 more active non-Thalassemia gene
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Define: Phenotype is very subtle and they are most often undiagnosed. The MCV may be slightly below normal (75-80 fL vs. 80-85 fL)
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Silent Alpha Thalassemia carrier
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Define: Clinically normal, but have a low MCV in the 70-75 fL (reference 80-85). Mild anemia and slight microcytosis (small than normal erythrocytes). Frequently misdiagnosed as having iron-deficiency anemia.
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Alpha-thalassemia trait (one functional gene (either a1 or a2)
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Define: Have moderately sever hemolytic condition characterized by fatigue, discomfort and splenogmegaly. They usually have a normal lifespan.
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HbH disease.
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What is HbH?
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A tetramer of hemoglobin B.
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Define: disease where an individual has no functional alpha gene.
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Hb Barts (hydrops fetalis)
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What are the two types of beta thalassemia?
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Thalassemia minor
Thalassemia major |
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What is the difference between beta thalassemia trait and disease?
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Thalassemia trait have one normal beta globin gene and one defective beta gene. Generally assymptomatic.
Thalassemia disease two defective gnees. which are anemic. |
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Why does ineffective erythropoeisis with beta thalassemia major?
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Excess alpha-globin causing it to preceitpate in the red cell and damage the cell membrane.
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Wha tis the treatment for Beta Thalassemia major?
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3-4 week blood transfunsion and iron chelaters.
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What is the most common mechanism of the alpha thalassemias?
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Gene deletions in the alpha gene locus arise from unequal crossover s that result from mispairing and crossin gover within homologous blocks of sequence repeated in this region.
The alpha2 and/or alpha1 is lost in the crossing over. |
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Are most beta-thalassemias caused by deletion?
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No, they are not. They are caused by point mutations.
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Define: Results in a shift of the reading frame.
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Frameshift
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Define: Results in a change of a stop codon.
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Read-through
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Define: Results in the substitution of one A.A. for another A.A.
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Missense.
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Define: Results in the change of a coding codon to a stop codon.
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Nonsense
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What is the difference between genomic DNA and cDNA for a particular gene?
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The presence of introns in the genomic DNA
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Give the consensus sequence at the 5' donor boundary.
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exon-A-G-BREAK-G-T-pu-A-G-T-intron
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What is the consensus sequence at the 3' acceptor boundary for an intron?
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intron-T-T-N-C-A-G-BREAK-G-exon
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Other than splicing what is required to generate a fully functional mRNA?
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Capping
Polyadenylation |
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Reading left to right (5"-->>3') is this the coding strand?
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Yes! It contains the same sequnce information as in mRNA.
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Which strand(5'->3' or 3'->5') is the template strand?
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Bottom one 3'-> 5'
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Which strand coding or noncoding (template) strand is the RNA polymerase bound to during transcription?
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Template (bottom) strand
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