The genes for pod shape and colour assort independently - VCE - SSCE Biology - Question 33 - 2015 - Paper 1
Question 33
The genes for pod shape and colour assort independently. A cross was performed between two plants that are heterozygous for both pod shape and colour. The ratio of p... show full transcript
Worked Solution & Example Answer:The genes for pod shape and colour assort independently - VCE - SSCE Biology - Question 33 - 2015 - Paper 1
Step 1
Determine the Genotype of Parents
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Answer
The parental plants are heterozygous for both traits, which means their genotypes can be represented as AaBb, where A represents inflated pods, a represents constricted pods, B represents green color, and b represents yellow color.
Step 2
Set Up a Punnett Square
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Answer
To predict the offspring ratios, we can use a 4x4 Punnett square considering the independent assortment of the two traits. The gametes from each parent would be AB, Ab, aB, and ab.
Step 3
Analyze the Offspring Ratios
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Answer
Upon filling in the Punnett square, we find the following phenotypic ratios:
9 Inflated Green (A_B_)
3 Inflated Yellow (A_bb)
3 Constricted Green (aaB_)
1 Constricted Yellow (aabb)
This results in a total phenotype ratio of 9:3:3:1.
Step 4
Select the Correct Answer Choice
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Answer
Based on the analysis, the correct phenotype ratio observed in the offspring is:
C. 9 inflated, green : 3 constricted, green : 3 inflated, yellow : 1 constricted, yellow.
