Inheritance — IGCSE Sciences - Co-Ordinated (0654) questions by topic
Inheritance questions are few but consistently substantial: 5 from the 2023 and 2024 papers, worth 8 to 10 marks, built around pedigree charts for albinism and cystic fibrosis, defining inheritance itself, and working out genotype probabilities for conditions such as polydactyly.
Calculate and identify sit alongside state, complete and explain among the top command words, since pedigree questions demand both correct genetics reasoning and a right numerical likelihood. Submit your pedigree-chart and probability answers for instant marking, so a genotype misread or a percentage slip is caught in the moment rather than carried through a whole family tree of reasoning.
What examiners look for
- Examiners note fewer candidates than expected correctly identified four people with a heterozygous genotype from a pedigree chart.
- A recurring criticism is failing to correctly determine the percentage likelihood of offspring not inheriting a condition such as polydactyly.
- Very few candidates could give a correct definition of the term gene.
- Popular incorrect responses to a genetics question included XX, X, Y and sperm in place of the expected answer.
- Reports note that some candidates did correctly determine that five people in a family had polydactyly.
October–November 2024, Paper 31
Tick the correct definition of inheritance from: inheritance is the transmission of genetic information from the environment; inheritance is the transmission of physical…
Answer this question and get it marked →October–November 2024, Paper 42
Fig. 7.1 summarises mitosis and meiosis in an organism (a parental cell dividing by mitosis to give cells A, and by meiosis through stages to give cell B). The parental cells in…
Answer this question and get it marked →May–June 2023, Paper 43
Albinism is an inherited condition giving no skin pigments. The allele for albinism is recessive a; for no albinism dominant A. Fig. 7.1 is a pedigree chart of albinism in one…
Answer this question and get it marked →October–November 2023, Paper 32
Polydactyly is a condition that results in the growth of extra fingers or toes. The allele for polydactyly is dominant D. The allele for no polydactyly is recessive d. Table 4.1…
Answer this question and get it marked →October–November 2023, Paper 41
Fig. 1.1 is a pedigree diagram for the inheritance of a genetic condition called cystic fibrosis. The allele for cystic fibrosis is recessive a. The allele for no cystic fibrosis…
Answer this question and get it marked →Other IGCSE Sciences - Co-Ordinated topics
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