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A gardener grows a species of plant that has either red or white flowers - OCR Gateway - GCSE Biology (Combined Science) - Question 11 - 2023 - Paper 8
Question 11
A gardener grows a species of plant that has either red or white flowers. The colour of the flowers is controlled by a single pair of alleles, R and r. The gardener... show full transcript
Worked Solution & Example Answer:A gardener grows a species of plant that has either red or white flowers - OCR Gateway - GCSE Biology (Combined Science) - Question 11 - 2023 - Paper 8
Step 1
Explain why the offspring in the diagram are all red.
Answer
The offspring are all red because red is the dominant trait. In this cross, the red flower parent provides the dominant allele (R), and since both parents of the offspring have red flowers, they can only exhibit the dominant phenotype.
Step 2
Step 3
Predict the probability that the next generation of plants will have white flowers.
Answer
To predict the probability, we start with a genetic cross between a heterozygous red flower (Rr) and a homozygous white flower (rr).
The Punnett square for this cross is:
R r
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r | Rr | rr |
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r | Rr | rr |
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From the diagram, the possible offspring are:
- 50% Rr (red flowers)
- 50% rr (white flowers)
Thus, the probability of obtaining a plant with white flowers is:
P(white) = rac{1}{2}