Question

purple is dominant to white. a heterozygous purple flower is crossed with a white flower. what are the genotypes and phenotypes of the offspring?

Explanation:

Step1: Define alleles

Let \(P\) represent the dominant allele for purple and \(p\) represent the recessive allele for white. A heterozygous purple flower has the genotype \(Pp\) and a white - flower has the genotype \(pp\).

Step2: Set up the Punnett - square

The possible gametes from the \(Pp\) parent are \(P\) and \(p\), and the only possible gamete from the \(pp\) parent is \(p\). The Punnett - square has two columns (gametes from \(Pp\): \(P\) and \(p\)) and one row (gamete from \(pp\): \(p\)).

Step3: Fill in the Punnett - square

When we combine the gametes, we get two genotypes: \(Pp\) and \(pp\).

Step4: Determine genotypes and phenotypes

The genotypes of the offspring are \(Pp\) and \(pp\) in a 1:1 ratio. Since \(P\) is dominant to \(p\), the phenotype of \(Pp\) is purple and the phenotype of \(pp\) is white. So the phenotypes are purple and white in a 1:1 ratio.

Answer:

Genotypes: \(Pp:pp = 1:1\); Phenotypes: Purple:White = 1:1