When Mendel crossed two purple-flowered pea plants with each other, he obtained a phenotypic ratio of 3:1 (purple-flowered pea plants to white-flowered pea plants). His results are consistent with which of the following sets of parents?

A. Homozygous dominant purple pea plant and heterozygous white pea plant
B. Heterozygous purple pea plant and homozygous dominant purple pea plant
C. Homozygous dominant purple pea plant and homozygous recessive white pea plant
D. Heterozygous purple pea plant and heterozygous purple pea plant

The correct answer to the question is D, as crossing two heterozygous purple-flowered pea plants (Pp) results in a 3:1 phenotypic ratio of purple to white flowers. This occurs because of the different combinations of dominant and recessive traits in the offspring. Therefore, Mendel's observations align with this genetic outcome.
;

Answered by Anonymous | 2025-07-11

Gregor Mendel's experiments with pea plants laid the foundation for understanding inheritance patterns. In his experiments, Mendel observed that when he crossed two heterozygous plants (known as monohybrid crosses), the resulting offspring exhibited a 3:1 phenotypic ratio in traits such as flower color.
Explanation of the Problem:
When Mendel crossed two purple-flowered pea plants and obtained a phenotypic ratio of 3:1 (three purple-flowered plants for every one white-flowered plant), this suggested that the purple-flowered plants were not all homozygous dominant. Instead, they were likely heterozygous.
Parental Genotypes:

Mendel's purple-flowered plants were represented by the genotype 'Pp,' where 'P' denotes the dominant purple allele and 'p' denotes the recessive white allele.
Both plants being crossed were heterozygous, so their genotypes were 'Pp.'
The possible gametes from each parent are 'P' and 'p.'

Punnett Square Analysis:
When you set up a Punnett square for two heterozygous (Pp) plants, you get the following combinations for their offspring:

PP (homozygous dominant) = Purple
Pp (heterozygous) = Purple
Pp (heterozygous) = Purple
pp (homozygous recessive) = White

So, the phenotypic ratio of the offspring would be 3 purple-flowered plants to 1 white-flowered plant, which matches the observed 3:1 ratio.
Based on this analysis, the correct answer is (D) Heterozygous purple pea plant and heterozygous purple pea plant .

Answered by OliviaLunaGracy | 2025-07-21