Inheritance: OCR GCSE Combined Science A questions

Every OCR GCSE Combined Science A exam question on B5.1 Inheritance, 2018–2025, with its mark scheme and examiner’s report.

All 93 questions on Inheritance, as a list

June 2025, Biology Paper 2 Foundation, Q7 (1 mark): Scientists have developed a detailed understanding of the human genome. Which of these is a benefit from developing this understanding? A Discovering new antibi
June 2025, Biology Paper 2 Foundation, Q9 (1 mark): The diagram shows a genetic cross for inheriting cystic fibrosis. Cystic fibrosis is a recessive inherited condition. Egg Cc Sperm Cc C c C C CC Cc c c cC cc Wh
June 2025, Biology Paper 2 Foundation, Q12(b) (4 marks): Complete the sentences to describe the genetic material. Use words from the list. diploid genes genome genotype haploid heterozygous homozygous variation The en
June 2025, Biology Paper 2 Foundation, Q12(c) (3 marks): Phenotypes, such as height, are determined by genetics, the environment or a combination of both. State a phenotype that is determined by each of the following.
June 2025, Biology Paper 8 Higher, Q1 (1 mark): The diagram shows a genetic cross for inheriting cystic fibrosis. Cystic fibrosis is a recessive inherited condition. Egg Cc Sperm Cc C c C C CC Cc c c cC cc Wh
June 2025, Biology Paper 8 Higher, Q12(a) (2 marks): Variation in a characteristic can be: • caused by genes only, the environment only or both • classified as continuous or discontinuous variation. Draw three lin
June 2025, Biology Paper 8 Higher, Q12(b)(i) (2 marks): Complete the sentences about human genetics. Use words from the list. alleles amino acids gametes genome mutations nucleus proteins recessive The entire genetic
June 2025, Biology Paper 8 Higher, Q12(b)(ii) (1 mark): Genetics determine a person’s sex. Determine the sex of the person whose chromosomes are shown in Fig. 12.1. Give a reason for your answer. Sex of the person Ex
June 2025, Biology Paper 8 Higher, Q12(b)(iii) (1 mark): Fig. 12.2 shows the karyotype of a human who has a genetic condition called Down’s Syndrome. Fig. 12.2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
June 2025, Biology Paper 8 Higher, Q13(b) (1 mark): The BRCA1 gene and the BRCA2 gene are associated with an increased risk of developing breast cancer. Scientists discovered the link between these genes and dise
June 2025, Biology Paper 8 Higher, Q16(c) (3 marks): The malaria protist can reproduce asexually by mitosis. At a different point in its lifecycle, the malaria protist reproduces sexually by meiosis. State three d
June 2024, Biology Paper 2 Foundation, Q5 (1 mark): Eye colour, height and weight in humans all show variation. Which of these are examples of continuous variation? A Eye colour and height B Eye colour, height an
June 2024, Biology Paper 2 Foundation, Q10 (1 mark): Which row is a correct comparison of meiosis and mitosis? Involves cell Halves the number Requires DNA division of chromosomes replication A both meiosis only b
June 2024, Biology Paper 2 Foundation, Q11(a) (2 marks): Draw lines to connect each term used in inheritance with its correct definition. Term Definition a change in the structure of DNA Chromosomes different versions
June 2024, Biology Paper 2 Foundation, Q11(b) (2 marks): Which terms describe sex cells in humans? Tick (✓) two boxes. Diploid Double helix Gamete Genome Specialised Undifferentiated [2]
June 2024, Biology Paper 2 Foundation, Q11(c)(i) (3 marks): A pea plant with green pods is crossed with a pea plant with yellow pods. All the pods on the new plant are green. Complete the sentences about the pea pods. Us
June 2024, Biology Paper 2 Foundation, Q11(c)(ii) (2 marks): The new plants with green pods are then crossed. What is the probability that a plant from this cross will have yellow pods? Complete the genetic diagram to exp
June 2024, Biology Paper 8 Higher, Q2 (1 mark): Which row is a correct comparison of meiosis and mitosis? Involves cell Halves the number Requires DNA division of chromosomes replication A both meiosis only b
June 2024, Biology Paper 8 Higher, Q12(b)(i) (2 marks): Pea pods are either green or yellow. The allele for green is dominant over the allele for yellow. The table shows some information about three different pea pod
June 2024, Biology Paper 8 Higher, Q12(b)(ii) (3 marks): A gardener crosses a plant that has green pods with a plant that has yellow pods. The gardener thinks both these plants have a homozygous genotype. The result i
June 2024, Biology Paper 8 Higher, Q12(b)(iii) (1 mark): The ratio the gardener achieved was 5 green to 1 yellow. Suggest why this does not match either of the offspring ratios. [1]
June 2023, Biology Paper 2 Foundation, Q1 (1 mark): Which word describes the entire genetic material of an organism? A Chromosome B Genome C Nucleus D Phenotype Your answer [1]
June 2023, Biology Paper 2 Foundation, Q16(a)(i) (2 marks): Explain why the offspring in the diagram are all red. [2]
June 2023, Biology Paper 2 Foundation, Q16(a)(ii) (1 mark): The offspring are all heterozygous for flower colour. What is meant by the term heterozygous? [1]
June 2023, Biology Paper 2 Foundation, Q16(b) (3 marks): The gardener crosses one of these offspring plants with a plant that is homozygous for white flowers. Predict the probability that the next generation of plants
June 2023, Biology Paper 2 Foundation, Q16(c)(i) (3 marks): The gardener counted 97 plants. Calculate the percentage of these plants that have blue flowers. Give your answer to the nearest whole number. Percentage of pla
June 2023, Biology Paper 2 Foundation, Q16(c)(ii) (1 mark): What evidence is there in the graph that flower colour is an example of discontinuous variation in this species? [1]
June 2023, Biology Paper 2 Foundation, Q16(d) (2 marks): The male gametes of a plant are called pollen. The sentences in the text box are about pollen. There are two words in the sentences that are not correct. Put ri
June 2023, Biology Paper 8 Higher, Q11(a)(i) (2 marks): Explain why the offspring in the diagram are all red. [2]
June 2023, Biology Paper 8 Higher, Q11(a)(ii) (1 mark): The offspring are all heterozygous for flower colour. What is meant by the term heterozygous? [1]
June 2023, Biology Paper 8 Higher, Q11(b) (3 marks): The gardener crosses one of these offspring plants with a plant that is homozygous for white flowers. Predict the probability that the next generation of plants
June 2023, Biology Paper 8 Higher, Q11(c)(i) (3 marks): The gardener counted 97 plants. Calculate the percentage of these plants that have blue flowers. Give your answer to the nearest whole number. Percentage of pla
June 2023, Biology Paper 8 Higher, Q11(c)(ii) (1 mark): What evidence is there in the graph that flower colour is an example of discontinuous variation in this species? [1]
June 2023, Biology Paper 8 Higher, Q11(d) (2 marks): The male gametes of a plant are called pollen. The sentences in the text box are about pollen. There are two words in the sentences that are not correct. Put ri
June 2022, Biology Paper 2 Foundation, Q4 (1 mark): The diagram shows how a condition caused by a recessive gene mutation is inherited. Which child, A, B, C or D, will inherit and develop the condition? Parents M
June 2022, Biology Paper 2 Foundation, Q6 (1 mark): Which term is used to describe a pair of alleles that control a characteristic? A Gamete B Genome C Genotype D Phenotype Your answer [1]
June 2022, Biology Paper 2 Foundation, Q7 (1 mark): The kangaroo diploid chromosome number is 16. Which row shows the number of chromosomes found in each type of cell? Kangaroo cells Skin Sperm Egg A 8 8 16 B 8 1
June 2022, Biology Paper 2 Foundation, Q9 (1 mark): The diagram shows a genetic cross for seed shape in peas. R r Key R RR Rr Round seed r Wrinkled seed Rr rr Which prediction about the offspring is most likely?
June 2022, Biology Paper 2 Foundation, Q13(a) (1 mark): A student models the inheritance of sex using two coins. • The student puts a red sticker on both sides of one coin to represent a female. • They then put a red
June 2022, Biology Paper 2 Foundation, Q13(b)(i) (1 mark): Complete the column for the offspring. One has been done for you. [1]
June 2022, Biology Paper 2 Foundation, Q13(b)(ii) (1 mark): Calculate the ratio of boys to girls in the 10 offspring. Ratio of boys : girls = [1]
June 2022, Biology Paper 2 Foundation, Q13(b)(iii) (1 mark): The results do not match the expected ratio. What is the expected ratio of offspring for boys : girls? [1]
June 2022, Biology Paper 2 Foundation, Q13(c) (2 marks): Explain why the results do not match the expected ratio. Suggest how the student could develop the experiment to get closer to the expected result. [2]
June 2022, Biology Paper 8 Higher, Q1 (1 mark): The diagram shows a genetic cross for seed shape in peas. R r Key R RR Rr Round seed r Wrinkled seed Rr rr Which prediction about the offspring is most likely?
June 2022, Biology Paper 8 Higher, Q4 (1 mark): Which number per cell is halved during meiosis? A Chromosome B Gamete C Haploid D Nucleus Your answer [1]
June 2022, Biology Paper 8 Higher, Q15(a)(i) (1 mark): A male who is heterozygous for BRCA has children with a female who is homozygous recessive. How are they affected by the BRCA allele? Put ticks (✓) in the corre
June 2022, Biology Paper 8 Higher, Q15(a)(ii) (3 marks): What is the percentage probability of them having a child with an increased risk of developing breast cancer? Use a labelled genetic diagram to explain your ans
June 2022, Biology Paper 8 Higher, Q15(b) (6 marks): Breast cancer has many genetic and clinical factors that affect its development. A woman has her genome mapped because her mother had breast cancer. Medical ris
November 2021, Biology Paper 2 Foundation, Q3 (1 mark): Which is the correct combination of chromosomes that determine sex in humans? A XX in a female B XX in a male C XY in a female D YY in a male Your answer [1]
November 2021, Biology Paper 2 Foundation, Q13(a)(i) (2 marks): Complete Table 13.1 by choosing words from this list to identify the genetic term used to describe cell A and cell B. diploid genotype haploid phenotype [2]
November 2021, Biology Paper 2 Foundation, Q13(a)(ii) (2 marks): Give an explanation for each choice of word in Table 13.1. [2] Cell Genetic term Explanation A B Table 13.1
November 2021, Biology Paper 2 Foundation, Q13(b) (2 marks): Huntington’s disease (HD) is an inherited disorder of the nervous system caused by a dominant allele. A person with the allele for HD will not normally develop
November 2021, Biology Paper 2 Foundation, Q13(c) (1 mark): Huntington’s disease can cause death. Fig. 13.3 shows the occurrence of HD by age when symptoms first appear. 250 200 150 Frequency (cases per 100 million peopl
November 2021, Biology Paper 2 Foundation, Q13(d) (2 marks): Early studies in the UK showed one in 15 000 have the HD allele. There are 66 000 000 people in the UK. Calculate the number of people in the UK with the HD all
November 2021, Biology Paper 8 Higher, Q4 (1 mark): The mass of an individual is one example of their phenotype. Which row describes variation in mass of individuals within a population? Type of variation Influen
November 2021, Biology Paper 8 Higher, Q5 (1 mark): A flower homozygous dominant for colour is crossed with a homozygous recessive flower. What is the predicted percentage of heterozygous offspring? A 25% B 50% C
November 2021, Biology Paper 8 Higher, Q10 (1 mark): The human genome project mapped the human genome. This gave many benefits and risks. Which statement is an ethical issue arising from the mapping of the human g
November 2021, Biology Paper 8 Higher, Q14(a) (2 marks): The diagram shows two cells from a mosquito with a chromosome number of 6. Different types of cell division produced Cell A and Cell B. Cell A Cell B Name the t
November 2021, Biology Paper 8 Higher, Q14(b)(i) (1 mark): Within a species of mosquito there are some mosquito that need blood to lay eggs and others that do not. Why is this an example of discontinuous variation? [1]
November 2021, Biology Paper 8 Higher, Q14(b)(ii) (2 marks): What is the probability of a baby being male when humans sexually reproduce? Complete the genetic diagram to explain your answer. Male Female Probability = [2]
November 2020, Biology Paper 2 Foundation, Q4 (1 mark): Which statement about skin cells is correct? A They are diploid cells containing one set of chromosomes. B They are diploid cells containing two sets of chromos
November 2020, Biology Paper 2 Foundation, Q9 (1 mark): A scientist crossed a white flower with a purple flower. The white flower is homozygous recessive. The purple flower is heterozygous. The scientist uses this Pu
November 2020, Biology Paper 2 Foundation, Q10 (1 mark): Meiosis is a type of cell division that is needed to make gametes. Which diagram shows meiosis? n = number of chromosomes A B 1n 1n 2n 2n 1n 1n 2n 2n 1n 1n 1n 1
November 2020, Biology Paper 2 Foundation, Q13(a)(i) (1 mark): Belgian Blue cattle have a different muscle phenotype than other cattle. What is meant by the term phenotype? [1]
November 2020, Biology Paper 2 Foundation, Q13(a)(ii) (2 marks): Explain why Belgian Blue cattle have a different muscle phenotype. [2]
November 2020, Biology Paper 8 Higher, Q1 (1 mark): A scientist crossed a white flower with a purple flower. The white flower is homozygous recessive. The purple flower is heterozygous. The scientist uses this Pu
November 2020, Biology Paper 8 Higher, Q2 (1 mark): Meiosis is a type of cell division that is needed to make gametes. Which diagram shows meiosis? n = number of chromosomes A B 1n 1n 2n 2n 1n 1n 2n 2n 1n 1n 1n 1
November 2020, Biology Paper 8 Higher, Q5 (1 mark): The genetic cross shows how genes are passed from parents to offspring. tall tall A Hh Hh H h H h B C HH Hh Hh hh D tall tall tall short Which part of the genet
November 2020, Biology Paper 8 Higher, Q7 (1 mark): The phenotype of rabbits can be black or white fur. The allele for black fur is dominant. Which genetic cross identifies the genotype of a rabbit with black fur
November 2020, Biology Paper 8 Higher, Q9 (1 mark): Which statement about alleles and genes is correct? A Alleles are found in the cytoplasm, while genes are only found in the nucleus on the DNA. B Allele is just
June 2019, Biology Paper 2 Foundation, Q5 (1 mark): Which combination of sex chromosomes is correct for humans? A female XX male XX B female XY male XX C female XX male XY D female XX male YY Your answer [1]
June 2019, Biology Paper 2 Foundation, Q6 (1 mark): Huntington’s disease is a single gene disorder caused by a dominant allele (H). The Punnett square shows the genetic cross between two heterozygous parents. H h
June 2019, Biology Paper 2 Foundation, Q8 (1 mark): Which word describes the number of chromosomes in a human sperm cell? A Diploid B Dominant C Haploid D Recessive [1] Your answer
June 2019, Biology Paper 2 Foundation, Q11(e)(i) (2 marks): Write down two environmental factors that could affect pea pod length. 1 2 [2]
June 2019, Biology Paper 2 Foundation, Q11(e)(ii) (1 mark): Early genetic studies identified the colour of pea pods as green or yellow. Results suggested that the colour is an example of single gene inheritance. Why is i
June 2019, Biology Paper 2 Foundation, Q12(c)(i) (1 mark): Write down what is meant by the term genome. [1]
June 2019, Biology Paper 2 Foundation, Q12(c)(ii) (2 marks): Knowledge of the human genome could identify the genes affected by HIV. Write down two ways knowledge of the human genome could help with the treatment of HIV.
June 2019, Biology Paper 8 Higher, Q3 (1 mark): A genetic cross occurs between a heterozygous individual and a homozygous recessive individual. What is the probability of these individuals having offspring th
June 2019, Biology Paper 8 Higher, Q15(a)(ii) (1 mark): Compare the number of chromosomes in human germinal epithelium cells and human mature sperm cells. [1]
June 2019, Biology Paper 8 Higher, Q15(b) (2 marks): Describe the events that occur at Stage 1 and Stage 2 in Fig. 15.1. [2]
June 2018, Biology Paper 2 Foundation, Q7 (1 mark): Sperm are made by meiosis. Look at the diagram of meiosis. GERMINAL EPITHELIUM Repeated cell A division and growth B C D MATURE SPERM At which stage A, B, C or
June 2018, Biology Paper 2 Foundation, Q9 (1 mark): Genes control eye colour. The allele for brown eyes (B) is dominant over the allele for blue eyes (b). Look at the genetic cross. Bb x BB Choose the possible ou
June 2018, Biology Paper 2 Foundation, Q14(a) (2 marks): Some children can inherit a rare kidney condition called ARPKD. It is caused by a recessive allele. A pregnant woman has ARPKD. The baby’s father is heterozygou
June 2018, Biology Paper 2 Foundation, Q14(b)(i) (2 marks): It is estimated that 1 in 70 people in the UK is a carrier of ARPKD. The estimated population of the UK in 2011 was 63.2 million. Estimate the number of people
June 2018, Biology Paper 2 Foundation, Q14(b)(ii) (1 mark): Explain why this number is only an estimate and not the real number of carriers. [1]
June 2018, Biology Paper 2 Foundation, Q15(a) (1 mark): The ratio for 16 is missing. Calculate the ratio for 16 tosses. Answer = [1]
June 2018, Biology Paper 2 Foundation, Q15(b) (2 marks): None of the ratios match the expected ratio of males to females you would show in a genetic cross. Here are three statements about the results: Student A – The
June 2018, Biology Paper 2 Foundation, Q15(c) (1 mark): The students want to improve the method to get a result that matches the expected ratio. Write down one way to improve the method. [1]
June 2018, Biology Paper 8 Higher, Q14(a) (1 mark): Look at the diagram of a pair of human chromosomes. Eye colour allele Eye colour allele Hair colour allele Hair colour allele Skin colour alleles Skin colour al
June 2018, Biology Paper 8 Higher, Q14(b)(i) (1 mark): How many chromosomes are there in a single human pancreas cell? [1]
June 2018, Biology Paper 8 Higher, Q14(b)(ii) (1 mark): Some individuals have a copy of the gene that would cause diabetes but do not have the disorder. Suggest a reason why. [1]
June 2018, Biology Paper 8 Higher, Q14(c)(i) (1 mark): What name is given to a change in the PKD1 gene that causes ADPKD? [1]
June 2018, Biology Paper 8 Higher, Q14(c)(iii) (2 marks): A pregnant woman is heterozygous for ADPKD. The baby’s father does not have ADPKD and is homozygous recessive. ADPKD is caused by a dominant allele (D). What is

Questions, mark schemes and examiner’s reports are © OCR, from their published past papers. Plumi isn’t affiliated with any exam board. Want whole papers? Full past papers.

Rather write your answers by hand on iPad? Plumi marks them against the same mark schemes.

3,411 questions