ABDOMINAL
THALASSEMIA
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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adenine for thymine
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lysine for valine
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valine for glutamic acid
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glutamic acid for valine
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Detailed explanation-1: -Sickle cell anemia is caused by homozygous sickle mutation (Hb SS). The sickle mutation causes substitution of a valine for glutamic acid as the seventh amino acid of the beta globin chain.
Detailed explanation-2: -Valine is a hydrophobic amino acid, whereas glutamic acid is hydrophilic: as position 6 of the globin is externally situated, the solubility of the HbS molecule is much reduced compared to HbA, especially in the deoxygenated state. Deoxy-HbS polymerizes the contact points between molecules involving the 6 valines.
Detailed explanation-3: -Sickle-cell anemia is caused by a point mutation in the -globin chain of hemoglobin, replacing the amino acid glutamic acid with the less polar amino acid valine at the sixth position of the chain. The mutation occurs in exon 1 and changes the nucleic acid sequence from GAG to GTG.