If you cross pea plants that are both heterozygous for purple flowers and yellow seeds ( PpYy), and you examine 800 offspring for flower and seed color, about how many do you expect to have white flowers and green seeds?
A) 450
B) All of them (800)
C) 50
D) 150
E) None of them

Question

Quizplus · Accepted Answer

The cross of two heterozygous pea plants (PpYy x PpYy) involves two traits, each with two alleles: P (purple flowers) is dominant over p (white flowers), and Y (yellow seeds) is dominant over y (green seeds). To find the offspring with white flowers and green seeds (ppy), we use a Punnett square or the forked-line method. Each trait segregates independently according to Mendel's law of independent assortment. The probability of pp (white flowers) is 1/4, and the probability of yy (green seeds) is also 1/4. Multiplying these probabilities gives 1/16 for the combination of pp and yy in any given offspring. Therefore, out of 800 offspring, 800 * (1/16) = 50 are expected to have white flowers and green seeds.

If You Cross Pea Plants That Are Both Heterozygous for Purple