Monohybrid inheritance: past paper questions
Real questions on monohybrid inheritance
The newest 20 of 30 written questions. Open one to see it on the real paper.
- 0610/32 · February/March 2026 · Q6a(i)[3]
Two pea plants with the genotypes Rr and rr for seed shape are bred together. Complete the Punnett square by writing in the genotypes of the gametes and the genotypes of the offspring for this cross. Calculate the phenotypic ratio. (a) (i)
See it on the paper → - 0610/42 · February/March 2026 · Q5a(iii)[3]
Complete the Punnett square to determine the genotypes and phenotypic ratio of the offspring. male female The phenotypic ratio of the offspring is:
See it on the paper → - 0610/42 · February/March 2026 · Q5a(iv)[1]
State the name of this type of monohybrid inheritance.
See it on the paper → - 0610/33 · May/June 2025 · Q6c(ii)[3]
The flower petals of this fava bean plant have coloured spots. The allele for black spots is dominant and is represented by the letter B. The allele for yellow spots is recessive and is represented by the letter b. A plant with flowers with black spots was crossed with a plant with flowers with yellow spots. The Punnet...
See it on the paper → - 0610/42 · May/June 2025 · Q1c[5]
Cystic fibrosis is an inherited condition in humans caused by a recessive allele of a gene. There are two alleles for this gene: the allele for no cystic fibrosis is represented by the letter F the allele for cystic fibrosis is represented by the letter f. • • Two heterozygous parents wanted to have a child. parental p...
See it on the paper → - 0610/43 · October/November 2024 · Q5b[2]
State all the possible genotypes of chicken 2 and chicken 7 in Fig. 5.1. chicken
See it on the paper → - 0610/43 · October/November 2024 · Q5c[5]
Complete the genetic diagram to show the results of a cross between chicken 5 and chicken 6 in Fig. 5.1. chicken 5 parental phenotypes × parental genotypes × gametes chicken 6 , , offspring genotypes
See it on the paper → - 0610/43 · October/November 2024 · Q5d[1]
State one example of codominance in humans.
See it on the paper → - 0610/33 · May/June 2024 · Q3a(i)[3]
State the genotypes of plants 1, 4 and 6 in Fig. 3.1. plant plant plant
See it on the paper → - 0610/33 · May/June 2024 · Q3a(ii)[3]
Describe how a gardener could use selective breeding to grow plants that only produce blue flowers.
See it on the paper → - 0610/33 · May/June 2024 · Q3b[3]
A different type of plant can produce red flowers or white flowers. The allele for red flowers is dominant and is represented by the letter R. The allele for white flowers is recessive and is represented by the letter r. Two plants were crossed. Complete the Punnett square by writing in: • the colours of the parent pla...
See it on the paper → - 0610/04 · Specimen 2023 · Q3c(i)[3]
State the genotypes of the people identified as P, Q and R in Fig. 3.3. P Q R
See it on the paper → - 0610/04 · Specimen 2023 · Q3c(ii)[1]
The couple S and T are expecting another child. State the probability that the child will have haemophilia.
See it on the paper → - 0610/04 · Specimen 2023 · Q3c(iii)[2]
Describe what is meant by the term sex-linked characteristic. [Total: 15]
See it on the paper → - 0610/33 · October/November 2023 · Q6a[6]
A student investigated variation in flower colour in pea plants. The student counted the number of pea plants that had purple flowers and the number of pea plants that had white flowers. Fig. 6.1 shows the results. 100 90 80 70 60 number of pea plants 50 40 30 20 10 0 purple white flower colour Fig. 6.1 Use the informa...
See it on the paper → - 0610/33 · October/November 2023 · Q6b[2]
Some features of organisms show discontinuous variation. The term discontinuous variation is in the box on the left. The boxes on the right show some features of organisms. Draw two lines from ‘discontinuous variation’ to two features that show discontinuous variation. blood group in humans body length in reptiles disc...
See it on the paper → - 0610/32 · February/March 2023 · Q3a(i)[1]
State the number of males with Huntington’s disease in Fig. 3.1.
See it on the paper → - 0610/32 · February/March 2023 · Q3a(ii)[2]
State the two possible genotypes for person 3 in Fig. 3.1. and
See it on the paper → - 0610/32 · February/March 2023 · Q3a(iii)[1]
State the evidence from Fig. 3.1 that suggests that the allele for Huntington’s disease is dominant.
See it on the paper → - 0610/32 · February/March 2023 · Q3b[3]
A person that is heterozygous for Huntington’s disease has a child with a person that is homozygous recessive. Complete the Punnett square in Fig. 3.2 by writing in the gametes and offspring for this cross and calculate the percentage chance of the child inheriting Huntington’s disease. Percentage chance of the child i...
See it on the paper →
What examiners said
Comprehensive responses • A significant number of candidates completed the Punnet square accurately and gave an acceptably expressed ratio for the phenotypes produced. Limited responses • A significant number of candidates made no attempt to answer the question, indicating that they would benefit from more practice at this skill. • Some candidates completed a heterozygous cross. • A number of can...
— Examiner report, February/March 2026, 0610/32 Q6(a)(i) (Cambridge)
Comprehensive responses • Many candidates were able to give the male and female genotypes and predict the offspring genotypes. Limited responses • Most candidates omitted the sex when giving the phenotypic ratio. • A small number of candidates omitted the sex chromosomes in the Punnett square.
— Examiner report, February/March 2026, 0610/42 Q5(a)(iii) (Cambridge)
Comprehensive responses • Many candidates gave the type of inheritance as ‘sex-linked’. Limited responses • Common incorrect responses included codominance and monohybrid inheritance. • A small number of candidates omitted this question.
— Examiner report, February/March 2026, 0610/42 Q5(a)(iv) (Cambridge)
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