Sickle cell anemia is a serious disease in which the body makes an abnormal form of the protein hemoglobin, which causes red blood cells to deform. The normal allele results in disc-shaped cells, while the sickle cell allele results in sickle-shaped alleles.

At the molecular level, an individual heterozygous for sickle cell disease has cells that are

Question

Sickle cell anemia is a serious disease in which the body makes an abnormal form of the protein hemoglobin, which causes red blood cells to deform. The normal allele results in disc-shaped cells, while the sickle cell allele results in sickle-shaped alleles.

At the molecular level, an individual heterozygous for sickle cell disease has cells that are

BlackTom AI · Accepted Answer

Question context: Sickle cell anemia involves alleles for hemoglobin; heterozygous individuals (AS) have a mixture of normal and abnormal hemoglobin.
Option 1: 'a mix of sickle-shaped and disc-shaped.' This aligns with the concept of heterozygous advantage and codominance, where some red blood cells may sickle under low oxygen while others remain disc-shaped when oxygenated. Thus, a mixed population of cell shapes is expected.
Option 2: 'None of these is correct.' This is inaccurate because there is a well-supported description for heterozygotes in sickle cell genetics, namely the presence of both cell forms.
Option 3: 'all sickle-shaped.' This would imply homozygous for the sickle allele (SS), not heterozygous AS, so it’s incorrect for a heterozygous individual.
Option 4: 'all disc-shaped.' This would imply no sickling at all, which is not the case in heterozygotes, since they produce some HbS and can exhibit sickling under certain conditions.
In summary, the heterozygous genotype yields a coexistence of normal and abnormal red blood cells, reflecting the mixed cell morphology described in option 1.

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