Question

name: _________________________ period: date: learning check 5b \i can explain the probability of dominant and recessive traits for flowers in pea plant\ • the cross below shows the trait for pea plants. purple color flower (b) is dominant over (b) white flowers. punnett square image 1. what is the probability (%) of having white flowers? __________ 2. how is it possible to produce a white flower? explain how this is genetically possible.

Explanation:

Question 1

Step1: Count total outcomes

The Punnett square has 4 cells (BB, Bb, Bb, bb), so total outcomes \( n = 4 \).

Step2: Count white - flower outcomes

White flowers have genotype \( bb \), and there is 1 such cell.

Step3: Calculate probability

Probability \( P=\frac{\text{Number of white - flower outcomes}}{\text{Total outcomes}}\times100\%=\frac{1}{4}\times100\% = 25\% \).

White flowers have the recessive genotype \( bb \). For a white flower to be produced, both parent plants must contribute the recessive allele (\( b \)). In the given cross, the pistil (female) can contribute \( b \) and the pollen (male) can contribute \( b \). When a \( b \) from the female and a \( b \) from the male combine during fertilization, the offspring has the genotype \( bb \), which expresses the recessive white - flower trait. Since the purple allele (\( B \)) is dominant, the recessive trait (white flowers) is only expressed when the dominant allele is not present (i.e., the genotype is homozygous recessive \( bb \)).

Answer:

\( 25\% \)

Question 2