If a pea plant with genotype Rr (round seeds) is crossed with another pea plant
Practice Questions
Q1
If a pea plant with genotype Rr (round seeds) is crossed with another pea plant with genotype rr (wrinkled seeds), what is the probability of obtaining a round-seeded plant?
0%
25%
50%
75%
Questions & Step-by-Step Solutions
If a pea plant with genotype Rr (round seeds) is crossed with another pea plant with genotype rr (wrinkled seeds), what is the probability of obtaining a round-seeded plant?
Step 1: Identify the genotypes of the parent plants. One plant has genotype Rr (round seeds) and the other has genotype rr (wrinkled seeds).
Step 2: Write down the possible combinations of alleles from the two parent plants when they are crossed.
Step 3: The Rr plant can contribute either R or r, while the rr plant can only contribute r.
Step 4: List the possible offspring genotypes from the cross: Rr (from R and r) and rr (from r and r).
Step 5: Determine which of the offspring genotypes result in round seeds. Rr has round seeds, while rr has wrinkled seeds.
Step 6: Count the total number of possible offspring genotypes. There are 2 possible genotypes: Rr and rr.
Step 7: Count how many of those genotypes are round-seeded. Only 1 genotype (Rr) is round-seeded.
Step 8: Calculate the probability of obtaining a round-seeded plant by dividing the number of round-seeded genotypes by the total number of genotypes: 1 (Rr) out of 2 (Rr and rr).
Step 9: Convert the fraction to a percentage: 1 out of 2 is 50%.
Genetic Crosses – Understanding how to determine the genotypes and phenotypes resulting from a cross between two organisms.
Probability in Genetics – Calculating the likelihood of specific traits appearing in offspring based on parental genotypes.
