PATHOLOGY MCQ
GENETICS AND DISEASE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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100% Pp (purple)
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50% Pp (purple); 50% pp (white)
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75% Pp (purple); 25% pp (white)
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25% PP, 50% Pp, 25% pp75% purple, 25% white
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Detailed explanation-1: -When a heterozygous purple flower (Rr) is crossed with a recessive white flower (rr), the progeny obtained are with the genotype (Rr), (Rr), (rr) and (rr). So, 50% of the progeny are with purple flowers (Rr) and 50% are with white flowers (rr). Q.
Detailed explanation-2: -P is the dominant allele, whereas p is the recessive allele. Here, purple flower is dominant and white flower is recessive in pea plants. Therefore, the presence of atleast one P allele will give purple colour (dominant phenotype) to the flower. Thus, the PP is a homozygous dominant genotype.
Detailed explanation-3: -In Mendel’s pea plants, purple flowers are dominant to white flowers, and a single gene controls this trait. The possible genotypes for this trait are PP, Pp, and pp. An organism with a genotype of PP will have a phenotype of purple flowers, since two copies of the dominant allele (P) are present.