Can the student tell from an individual's blood type phenotype alone (no information is known about the parents) if that individual is heterozygous or homozygous for their blood type genotype? Explain for each possible blood type.
No, the student cannot determine whether an individual is heterozygous or homozygous for their blood type genotype based solely on the blood type phenotype.
For blood type A, an individual can have either genotype AA or AO. Both genotypes would result in the same blood type phenotype of type A. Therefore, the student cannot determine whether the individual is heterozygous (AO) or homozygous (AA) for blood type A.
Similarly, for blood type B, an individual can have either genotype BB or BO. Both genotypes would result in the same blood type phenotype of type B. Thus, the student cannot determine whether the individual is heterozygous (BO) or homozygous (BB) for blood type B.
For blood type AB, individuals who have this blood type phenotype must have the genotype AB. There is no variation or heterozygosity possible for blood type AB.
For blood type O, an individual with this blood type phenotype can only have the genotype OO. Again, there is no variation or heterozygosity possible for blood type O.
In conclusion, the student cannot determine whether an individual is heterozygous or homozygous for their blood type genotype based solely on the blood type phenotype, except in the case of blood type AB.