Question

An explanation of why plants with CCpp and ccPP genotypes have white petals while plants with the CcPp genotype have purple flowers is?

1) The dominant allele for Gene C provides an enzyme that converts Colorless Precursor→Colorless Intermediate, while the dominant allele for Gene P provides an enzyme that converts Colorless Intermediate→Purple Pigment.
2) The dominant allele for Gene C provides an enzyme that converts Colorless Intermediate→Purple Pigment, while the dominant allele for Gene P provides an enzyme that converts Colorless Precursor→Colorless Intermediate.
3) The dominant allele for Gene C provides an enzyme that converts Colorless Precursor→Purple Pigment, while the dominant allele for Gene P provides an enzyme that converts Colorless Intermediate→Colorless Precursor.
4) The dominant allele for Gene C provides an enzyme that converts Colorless Intermediate→Colorless Precursor, while the dominant allele for Gene P provides an enzyme that converts Colorless Precursor→Purple Pigment.

Answer 1

Plants with CCpp and ccPP genotypes have white petals because they lack one of the enzymes needed for purple pigment production, while plants with CcPp genotype have at least one dominant allele for each gene, leading to the complete production of purple pigment in the flowers.

Step-by-step explanation:

In genetics, the explanation of why plants with CCpp and ccPP genotypes have white petals while plants with the CcPp genotype have purple flowers is based on the biochemical pathway involving two genes and their corresponding enzymes.

The dominant allele for Gene C (C) provides an enzyme that converts Colorless Precursor→Colorless Intermediate, while the dominant allele for Gene P (P) provides an enzyme that converts Colorless Intermediate→Purple Pigment.

Therefore, both dominant alleles (C and P) are required to produce the purple pigment in the flowers. If either gene has only recessive alleles (cc or pp), the conversion process cannot proceed to produce the purple pigment, resulting in white petals.

Plants with a genotype of CCpp or ccPP lack one of the necessary enzymes in the pathway because the recessive alleles (pp or cc, respectively) do not produce a functional enzyme. Therefore, the biochemical conversion is incomplete, and the plants have white petals. In contrast, plants with a CcPp genotype have at least one dominant allele for each gene (C and P), allowing both steps in the pigment production pathway to occur, resulting in purple flowers.