Igcse Model Questions Vol1 2025 Biology Question 10

Practice essay / theory question 10 from the 2025 Igcse Model Questions Vol1 Biology examination. This question covers Mendelian Genetics, Pedigree Analysis, Gene Linkage, Ethics in Biotechnology .

Igcse Model Questions Vol1 2025 Biology Essay / Theory
Topics: Mendelian Genetics Pedigree Analysis Gene Linkage Ethics in Biotechnology
Question 10 IGCSE_MODEL_QUESTIONS_VOL1 • 2025 • BIOLOGY • essay

A plant breeder is developing a new tomato variety that is resistant to a fungal disease. Resistance is controlled by a single recessive allele (r). The breeder crosses a heterozygous resistant plant (Rr) with a homozygous susceptible plant (RR).

Question Parts

( a )
Predict the genotypic and phenotypic ratios expected in the F1 generation.
( b )
Two F1 plants are inter‑crossed. Calculate the probability that a randomly selected F2 seed will be resistant to the disease.
( c )
Occasionally the observed proportion of resistant seedlings deviates from 25 %. The breeder suspects that the resistance gene is linked to a gene controlling fruit size (S) with a recombination frequency of 10 %. Explain how a test cross could be used to confirm linkage and state the expected phenotypic ratios among the progeny if the two genes are linked with 10 % recombination.
( d )
Discuss two ethical considerations that should be taken into account before releasing a genetically modified tomato variety with disease resistance into the market.

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About This Question

This is Igcse Model Questions Vol1 2025 Biology Question 10. It is one of the essay questions from the 2025 Igcse Model Questions Vol1 Biology examination.

The question covers Mendelian Genetics, Pedigree Analysis, Gene Linkage, Ethics in Biotechnology .

View More Igcse Model Questions Vol1 2025 Biology Questions More Igcse Model Questions Vol1 Practice Questions Back to Questions

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