Jane has blue eyes and Keith has brown eyes - Edexcel - GCSE Biology - Question 2 - 2013 - Paper 1
Question 2
Jane has blue eyes and Keith has brown eyes.
They have a daughter Sue who has blue eyes.
The allele for brown eyes is dominant over the allele for blue eyes.
(i) Co... show full transcript
Worked Solution & Example Answer:Jane has blue eyes and Keith has brown eyes - Edexcel - GCSE Biology - Question 2 - 2013 - Paper 1
Step 1
Sue has the genotype
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Answer
Sue has blue eyes, which means she must have the genotype 'bb'. Therefore, the correct answer is C: bb.
Step 2
State the genetic term
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Answer
The genetic term used to describe an individual with two different alleles for the same gene is 'heterozygous'.
Step 3
Complete the Punnett square
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Answer
To complete the Punnett square for Jane (bb) and Keith (Bb), we can outline the possible gametes:
| B | b |
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b | Bb | bb |
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b | Bb | bb |
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The Punnett square indicates that there is a 50% chance of having a child with blue eyes (bb) and a 50% chance of having a child with brown eyes (Bb).
