Question

suppose we have a pea plant with purple flowers, determined by the dominant allele p. how might you determine whether the plant is homozygous (pp) or heterozygous (pp)?view available hint(s)for part across the plant with a true-breeding purple plant.perform a testcross: cross the plant with a white one, which must be homozygous recessive (pp).examine the plant's chromosomes with a microscope.perform a testcross: cross the plant with one with green seeds, which must be homozygous recessive (yy).

Answer 1

To check if a pea plant is homozygous or heterozygous for purple flowers, a testcross with a white-flowered (pp) plant is performed. Crosses between PpYY and ppYy or ppyy pea plants involve Punnett squares with four or sixteen squares, respectively, to analyze genotypic and phenotypic outcomes.

Step-by-step explanation:

To determine if a pea plant with purple flowers, which is a trait determined by the dominant allele P, is homozygous (PP) or heterozygous (Pp), one can perform a testcross with a white-flowered plant, which must be homozygous recessive (pp). The outcomes of this cross would reveal the genotype of the purple-flowered plant. If all offspring have purple flowers, the original plant is likely homozygous (PP). If any offspring have white flowers, the plant is heterozygous (Pp).

When looking at a cross between a PpYY and a ppYy pea plant, the possible genotypes for the offspring can be determined using a Punnett square. To calculate this, we need to consider each allele the parent can pass on. The PpYY plant can pass on PY alleles, and the ppYy plant can pass on pY or py. This results in a Punnett square with four squares, as there are two different possibilities from one parent (P or p from the PpYY plant) and two from the other (Y or y from the ppYy plant).

For a dihybrid cross, as in the case of a cross between PpYY and ppyy pea plants, a 16-square Punnett square is used to represent all possible combinations of the two genes being considered (flower color and pea color).