THE MOLECULAR BASIS OF INHERITANCE
GENE MUTATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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valine is substituted with proline.
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valine is substituted with glutamic acid.
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glutamic acid is substituted with proline.
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glutamic acid is substituted with 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. The resulting hemoglobin tetramer (alpha2/betaS2) is poorly soluble when deoxygenated.
Detailed explanation-2: -Sickle cell anemia results from the single amino acid substitution of valine for glutamic acid in the beta-chain owing to a nucleotide defect that causes the production of abnormal beta-chains in hemoglobin S.
Detailed explanation-3: -People who have sickle-cell anemia have a single amino acid substitution in their hemoglobin. The substitution is a switch from this glutamate to valine. This alteration causes hemoglobin molecules to clump, as reflected in a change in the shape of the red blood cells, which have a distorted, sickle shape.
Detailed explanation-4: -The sickle cell disease occurs when the sixth amino acid, glutamic acid is replaced by valine to change is structure and function.
Detailed explanation-5: -So, the correct answer is ‘GUG’.