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Inheritance: Eduqas A‑Level Biology questions

Every Eduqas A-Level Biology exam question on 2.5 Inheritance, 2016–2025, with its mark scheme and examiner’s report.

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2,061 questions

  1. Q5(b)(i)

    June 2025 · Component 2

    2 marks2.5 Inheritance
    The whole paper ↗
    June 2025 Component 2, question 5(b)(i): Using the information given, complete Table 5.2 giving all the possible genotypes of individuals with the blood groups shown. Use symbols IA, IB and IO to repre

  2. Q5(b)(ii)

    June 2025 · Component 2

    2 marks2.5 Inheritance
    The whole paper ↗
    June 2025 Component 2, question 5(b)(ii): A child with blood group O was born to parents with blood groups A and B. Complete the genetic diagram below to show a cross between these parents that could pr

  3. Q5(b)(iii)

    June 2025 · Component 2

    1 mark2.5 Inheritance
    The whole paper ↗
    June 2025 Component 2, question 5(b)(iii): State the probability that another child born to these parents will have blood group O. [1]

  4. Q5(d)(iii)

    June 2025 · Component 2

    3 marks2.5 InheritanceC.5 Nucleic acids and their functions
    The whole paper ↗
    June 2025 Component 2, question 5(d)(iii): Explain how the substitution of a nucleotide may cause a gene to code for a different protein. [3]

  5. Q5(d)(v)

    June 2025 · Component 2

    2 marksC.4 Biological reactions are regulated by enzymes2.5 Inheritance
    The whole paper ↗
    June 2025 Component 2, question 5(d)(v): Bombay blood group is a very rare blood type. People with this blood type always show up as type O on a blood test, but they can carry the allele for blood grou

  6. Q5(c)(i)

    June 2024 · Component 1

    2 marks2.5 Inheritance
    The whole paper ↗
    June 2024 Component 1, question 5(c)(i): Use the information to suggest why attempts to breed new useful varieties of avocado have low success rates. [2]

  7. Q3(b)(ii)

    June 2024 · Component 2

    2 marks2.5 Inheritance
    The whole paper ↗
    June 2024 Component 2, question 3(b)(ii): G6PD deficiency is caused by a recessive allele. Explain this statement. Use a suitable example from Image 3 to support your answer. [2] The following symbols

  8. Q3(b)(iii)

    June 2024 · Component 2

    3 marks2.5 Inheritance
    The whole paper ↗
    June 2024 Component 2, question 3(b)(iii): Using these symbols, state all the possible genotypes for the following individuals in Image 3.  [3] 4 5 6 10

  9. Q3(b)(iv)

    June 2024 · Component 2

    1 mark2.5 Inheritance
    The whole paper ↗
    June 2024 Component 2, question 3(b)(iv): A genetic screening test shows that individual 13 is a carrier of the allele for the G6PD deficiency. Determine the probability that a child of individuals 13 a

  10. Q4(c)

    June 2024 · Component 2

    3 marks2.5 Inheritance
    The whole paper ↗
    June 2024 Component 2, question 4(c): A group of scientists recently studied the genomes of the two forms of fish. The scientists found the two forms of fish had very similar genomes but there were

  11. Q6(a)

    June 2023 · Component 2

    3 marks2.5 Inheritance
    The whole paper ↗
    June 2023 Component 2, question 6(a): Give three practical precautions that should be taken to ensure that the offspring produced are only from the desired cross. [3]

  12. Q6(b)(i)

    June 2023 · Component 2

    3 marks2.5 Inheritance
    The whole paper ↗
    June 2023 Component 2, question 6(b)(i): results. [3] Table 6.1 Observed Expected O  E ( O  E ) 2 ( O  E ) 2 Phenotype number number E (O) (E) Glossy green leaves 64 Glossy striped leaves 12 Rough

  13. Q6(b)(ii)

    June 2023 · Component 2

    1 mark2.5 Inheritance
    The whole paper ↗
    June 2023 Component 2, question 6(b)(ii): State the number of degrees of freedom for these results. [1] Table 6.2 Degrees Probability of freedom 0.9 0.8 0.7 0.5 0.2 0.1 0.05 0.02 0.01 1 0.016 0.064 0.15

  14. Q6(b)(iii)

    June 2023 · Component 2

    1 mark2.5 Inheritance
    The whole paper ↗
    June 2023 Component 2, question 6(b)(iii): the probability of the results being significantly different from the expected ratio.  [1]  Probability =

  15. Q6(b)(iv)

    June 2023 · Component 2

    2 marks2.5 Inheritance
    The whole paper ↗
    June 2023 Component 2, question 6(b)(iv): State what conclusion can be made from these results and explain your answer.  [2]

  16. Q6(b)(v)

    June 2023 · Component 2

    4 marks2.5 Inheritance
    The whole paper ↗
    June 2023 Component 2, question 6(b)(v): With reference to the results of the cross, explain why the actual ratio of phenotypes obtained was different from the expected ratio. [4]

  17. Q1(b)(ii)

    June 2022 · Component 2

    1 mark2.5 Inheritance
    The whole paper ↗
    June 2022 Component 2, question 1(b)(ii): The data collected from each site were analysed separately using a type of chi2 test. State the null hypothesis that would have been tested. [1] Statistical ana

  18. Q6(c)(i)

    June 2022 · Component 2

    1 mark2.5 Inheritance
    The whole paper ↗
    June 2022 Component 2, question 6(c)(i): State what is meant by an X-linked condition. [1]

  19. Q6(c)(ii)

    June 2022 · Component 2

    4 marks2.5 Inheritance
    The whole paper ↗
    June 2022 Component 2, question 6(c)(ii): There are three possible gametes that can be produced by the male and female cats: XD, Xd, and Y, where D = unaffected and d = muscular dystrophy. Complete the

  20. Q6(d)

    June 2022 · Component 2

    2 marks2.5 Inheritance
    The whole paper ↗
    June 2022 Component 2, question 6(d): One form of muscular dystrophy in humans is called Duchenne muscular dystrophy (DMD). It is also inherited as a recessive, sex-linked condition. The inheritance
All 58 questions on Inheritance, as a list
  1. June 2025, Component 2, Q5(b)(i) (2 marks): Using the information given, complete Table 5.2 giving all the possible genotypes of individuals with the blood groups shown. Use symbols IA, IB and IO to repre
  2. June 2025, Component 2, Q5(b)(ii) (2 marks): A child with blood group O was born to parents with blood groups A and B. Complete the genetic diagram below to show a cross between these parents that could pr
  3. June 2025, Component 2, Q5(b)(iii) (1 mark): State the probability that another child born to these parents will have blood group O. [1]
  4. June 2025, Component 2, Q5(d)(iii) (3 marks): Explain how the substitution of a nucleotide may cause a gene to code for a different protein. [3]
  5. June 2025, Component 2, Q5(d)(v) (2 marks): Bombay blood group is a very rare blood type. People with this blood type always show up as type O on a blood test, but they can carry the allele for blood grou
  6. June 2024, Component 1, Q5(c)(i) (2 marks): Use the information to suggest why attempts to breed new useful varieties of avocado have low success rates. [2]
  7. June 2024, Component 2, Q3(b)(ii) (2 marks): G6PD deficiency is caused by a recessive allele. Explain this statement. Use a suitable example from Image 3 to support your answer. [2] The following symbols
  8. June 2024, Component 2, Q3(b)(iii) (3 marks): Using these symbols, state all the possible genotypes for the following individuals in Image 3.  [3] 4 5 6 10
  9. June 2024, Component 2, Q3(b)(iv) (1 mark): A genetic screening test shows that individual 13 is a carrier of the allele for the G6PD deficiency. Determine the probability that a child of individuals 13 a
  10. June 2024, Component 2, Q4(c) (3 marks): A group of scientists recently studied the genomes of the two forms of fish. The scientists found the two forms of fish had very similar genomes but there were
  11. June 2023, Component 2, Q6(a) (3 marks): Give three practical precautions that should be taken to ensure that the offspring produced are only from the desired cross. [3]
  12. June 2023, Component 2, Q6(b)(i) (3 marks): results. [3] Table 6.1 Observed Expected O  E ( O  E ) 2 ( O  E ) 2 Phenotype number number E (O) (E) Glossy green leaves 64 Glossy striped leaves 12 Rough
  13. June 2023, Component 2, Q6(b)(ii) (1 mark): State the number of degrees of freedom for these results. [1] Table 6.2 Degrees Probability of freedom 0.9 0.8 0.7 0.5 0.2 0.1 0.05 0.02 0.01 1 0.016 0.064 0.15
  14. June 2023, Component 2, Q6(b)(iii) (1 mark): the probability of the results being significantly different from the expected ratio.  [1]  Probability =
  15. June 2023, Component 2, Q6(b)(iv) (2 marks): State what conclusion can be made from these results and explain your answer.  [2]
  16. June 2023, Component 2, Q6(b)(v) (4 marks): With reference to the results of the cross, explain why the actual ratio of phenotypes obtained was different from the expected ratio. [4]
  17. June 2022, Component 2, Q1(b)(ii) (1 mark): The data collected from each site were analysed separately using a type of chi2 test. State the null hypothesis that would have been tested. [1] Statistical ana
  18. June 2022, Component 2, Q6(c)(i) (1 mark): State what is meant by an X-linked condition. [1]
  19. June 2022, Component 2, Q6(c)(ii) (4 marks): There are three possible gametes that can be produced by the male and female cats: XD, Xd, and Y, where D = unaffected and d = muscular dystrophy. Complete the
  20. June 2022, Component 2, Q6(d) (2 marks): One form of muscular dystrophy in humans is called Duchenne muscular dystrophy (DMD). It is also inherited as a recessive, sex-linked condition. The inheritance
  21. June 2022, Component 3, Q4(d)(i) (2 marks): Describe what is meant by the term autosomal dominant allele. [2]
  22. Autumn 2021, Component 1, Q3(d)(i) (1 mark): State the name given to a change in gene expression brought about by methylation.  [1]
  23. Autumn 2021, Component 1, Q3(d)(ii) (2 marks): Use the information given and your knowledge of protein synthesis to explain why the sweetness of the tomatoes will not increase after they have been stored at
  24. Autumn 2021, Component 2, Q5(a)(i) (2 marks): Based on these laws, state the phenotypes and the ratios you would expect in the offspring following a cross between the following parent plants: I. both plants
  25. Autumn 2021, Component 2, Q5(a)(ii) (2 marks): State what is meant by the term linkage and explain why Mendel’s law of independent assortment only applies if the genes are not linked. [2]
  26. Autumn 2021, Component 2, Q5(b) (5 marks): Corn cobs were produced by crossing parent plants that were heterozygous for both colour and appearance of the seeds. The phenotypes in the F1 can be seen in im
  27. Autumn 2021, Component 2, Q5(c)(i) (1 mark): State the null hypothesis for this test. [1]
  28. Autumn 2021, Component 2, Q5(c)(ii) (3 marks): Complete the table below to calculate the Chi2 statistic for these data. [3] observed expected (O–E )2 phenotype numbers numbers O–E (O–E)2 E O E purple; smooth
  29. Autumn 2021, Component 2, Q5(c)(iii) (5 marks): Based on these data the hypothesis was accepted but with low confidence. Use your calculated value of Chi2 and data from table 5.3 to explain this conclusion. 
  30. Autumn 2021, Component 3, Q9(b)(i) (1 mark): Describe what is meant by an epigenetic change in the DNA. [1] One example of epigenetic modification is the methylation of DNA that prevents transcription of a
  31. Autumn 2021, Component 3, Q9(b)(ii) (3 marks): Use the information in image 9.3 to explain how methylation of the NR3C1 gene could lead to higher incidences of stress-related mental illnesses in survivors of
  32. Autumn 2020, Component 2, Q1(a)(i) (1 mark): State the term currently used in genetics to describe the form or trait of a characteristic. [1]
  33. Autumn 2020, Component 2, Q1(a)(ii) (1 mark): Explain what is meant by the term pure breeding. [1]
  34. Autumn 2020, Component 2, Q1(a)(iii) (2 marks): Mendel’s ‘units of inheritance’ are now known as alleles. Explain why some characteristics always appear in the offspring produced from a cross, while others do
  35. Autumn 2020, Component 2, Q1(c)(i) (2 marks): Calculate the ratio of the following combinations of traits found in the F2 offspring. Give each value to one decimal place. [2] F2 trait smooth smooth wrinkled
  36. Autumn 2020, Component 2, Q1(c)(ii) (2 marks): Explain how these pure breeding parents produced the combinations of traits shown in the F2 offspring. [2]
  37. Autumn 2020, Component 2, Q1(d)(i) (1 mark): Suggest why this cross did not produce the same ratio of the combination of characters as found by Mendel in his experiment. [1]
  38. Autumn 2020, Component 2, Q1(d)(ii) (2 marks): Using your knowledge of meiosis, explain how plants producing purple flowers and round pollen grains could have been produced in this cross. [2]
  39. Autumn 2020, Component 2, Q2(d)(i) (2 marks): Name the genes that when mutated can trigger uncontrolled cell division and state the term used to describe the chemicals that can cause these mutations. [2] Ge
  40. Autumn 2020, Component 2, Q2(e) (3 marks): Scientists have used C. elegans to study epigenetic effects on genes that are involved in the control of the cell cycle and how these effects could trigger the
  41. Autumn 2020, Component 3, Q4(b) (2 marks): One type of Bartter syndrome is caused by a recessive allele found on chromosome number 1. The allele for functioning ion channels, N, is dominant to that for B
  42. June 2019, Component 2, Q4(b) (4 marks): In breeding experiments: • chestnut crossed with black always produced chestnut-black offspring, • chestnut-black crossed with other chestnut-black produced off
  43. June 2019, Component 2, Q4(e) (2 marks): Since the 1950s, nuclear weapons tests have taken place in the South Pacific. Suggest how this might have accounted for the emergence of the black phenotype on
  44. June 2019, Component 3, Q2(c) (3 marks): Alport’s Syndrome is an inherited condition which causes the thickening of the basement membrane of the glomerulus. This can lead to the retention of fluid in t
  45. June 2018, Component 1, Q4(c) (3 marks): Explain what has happened to produce a non-functional glycogen debranching enzyme. [3]
  46. June 2018, Component 1, Q4(d) (1 mark): Both parents are usually unaffected and it affects both males and females equally. How is this gene most likely to be inherited? [1]
  47. June 2018, Component 2, Q1(c)(i) (1 mark): Mark, by placing the letter f on the diagram, a possible locus for the gene that causes Fabry disease. [1]
  48. June 2018, Component 2, Q1(c)(ii) (2 marks): With reference to the positions of the gene loci explain the following observations: [2] I. Males with the f allele always suffer Fabry disease but females can
  49. June 2018, Component 2, Q1(d) (4 marks): Complete the genetic diagram below to show how Fabry disease might be inherited from parents neither of whom suffers from the condition and state the probabilit
  50. June 2018, Component 2, Q2(a)(ii) (1 mark): Use the photograph to deduce the sex of the mammal and explain your choice. [1]
  51. June 2018, Component 3, Q5(c)(i) (2 marks): Explain why a t-test was used to assess the significance of the differences in the results and not a Chi-squared test. [2]
  52. June 2017, Component 2, Q4(a)(i) (4 marks): Complete the genetic diagram below to show the expected outcome of crossing mice heterozygous at both loci. [4] Parental phenotype x Parental genotype x Gametes
  53. June 2017, Component 2, Q4(a)(ii) (1 mark): Give the ratio in which the following phenotypes would appear in the offspring. [1] Offspring phenotypes: normal agouti : solid black : cinnamon : solid brown P
  54. June 2017, Component 2, Q4(b)(i) (3 marks): Using the table provided, calculate χ2 to test this null hypothesis. [3] χ2 = ∑ (O – E)2 E χ2 =
  55. June 2017, Component 2, Q4(b)(ii) (1 mark): Choose an appropriate probability level and circle the critical value for χ2 in the table below: [1] Degrees Probability of 0.9 0.8 0.7 0.5 0.2 0.1 0.05 0.02 0.
  56. June 2017, Component 2, Q4(b)(iii) (2 marks): State whether you accept or reject the null hypothesis, and explain why. [2] A mutant form of the gene at locus II exists, called Avy, which results in hair whi
  57. June 2017, Component 2, Q4(c)(i) (1 mark): What name is given to the study of the control of gene expression by factors other than changes in the DNA sequence? [1] Normal allele (A) regulator gene agouti
  58. June 2017, Component 2, Q4(c)(iii) (3 marks): Explain how the addition of an increasing number of methyl groups to the inserted sequence of bases results in mice with a range of coat colours. [3]

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