Concept:A single point mutation in DNA can radically alter the primary, and thus tertiary/quaternary, structure of a protein.
Solution:- Sickle cell anemia is caused by a precise point mutation in the gene encoding the beta-chain of hemoglobin.
- This genetic error causes a highly polar, hydrophilic amino acid (Glutamic acid) at position 6 to be erroneously replaced by a highly non-polar, hydrophobic amino acid (Valine).
- Because valine is hydrophobic, it tries to hide from water by sticking to other hemoglobin molecules, causing the proteins to polymerize into long, sharp fibers that distort the red blood cell into a sickle shape.
Why other options are incorrect:- This is a specific memorization fact. Proline, Glutamine, and Glycine are not the specific amino acid substituted in this famous genetic disorder.
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