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Gene technologies: OCR A‑Level Biology B questions

Every OCR A-Level Biology B exam question on 5.1.3 Gene technologies, 2016–2025, with its mark scheme and examiner’s report.

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1,889 questions

  1. Q4(b)(i)

    June 2025 · Paper 3

    2 marks5.1.3 Gene technologies
    The whole paper ↗
    June 2025 Paper 3, question 4(b)(i): Complete the table to show the temperatures used in the three stages of a PCR cycle and the processes that occur at each temperature. Temperature (°C) Process S

  2. Q4(b)(ii)

    June 2025 · Paper 3

    2 marks5.1.3 Gene technologies
    The whole paper ↗
    June 2025 Paper 3, question 4(b)(ii): In theory, the number of DNA molecules can increase exponentially during PCR. Calculate the theoretical maximum number of DNA molecules that could be present af

  3. Q4(b)(iii)

    June 2025 · Paper 3

    1 mark5.1.3 Gene technologies
    The whole paper ↗
    June 2025 Paper 3, question 4(b)(iii): Suggest one reason why the theoretical maximum number of DNA molecules might not be achieved. [1]

  4. Q4(b)(iv)

    June 2025 · Paper 3

    1 mark5.1.3 Gene technologies
    The whole paper ↗
    June 2025 Paper 3, question 4(b)(iv): A version of PCR known as quantitative PCR (qPCR) is used to detect alleles that are associated with an increased risk of cancer. qPCR involves: • extracting mR

  5. Q4(b)(v)

    June 2025 · Paper 3

    2 marks5.1.3 Gene technologies
    The whole paper ↗
    June 2025 Paper 3, question 4(b)(v): The diagram shows a fluorescent probe used in qPCR. Before the probe has bound to cDNA After the action of Taq DNA polymerase Quencher (molecule that Fluorescen

  6. Q4(c)(i)

    June 2025 · Paper 3

    2 marks5.1.3 Gene technologies
    The whole paper ↗
    June 2025 Paper 3, question 4(c)(i): Samples containing DNA fragments are placed in the loading wells of the electrophoresis box before beginning electrophoresis. State one other substance that sho

  7. Q4(c)(ii)

    June 2025 · Paper 3

    2 marks5.1.3 Gene technologies
    The whole paper ↗
    June 2025 Paper 3, question 4(c)(ii): State and explain the purpose of the DNA fragments in lane 1 in the diagram. [2]

  8. Q4(c)(iii)

    June 2025 · Paper 3

    2 marks5.1.3 Gene technologies
    The whole paper ↗
    June 2025 Paper 3, question 4(c)(iii): State the lane numbers that indicate: • a genotype that is homozygous for the normal CYP17 allele • a genotype that is homozygous for the mutant CYP17 allele. •

  9. Q23

    June 2024 · Paper 1

    1 mark5.1.3 Gene technologies
    The whole paper ↗
    June 2024 Paper 1, question 23: Knockout mice are developed as model organisms for studying conditions such as diabetes. Which statement about the features of knockout mice is correct? A An ar

  10. Q35(a)

    June 2024 · Paper 1

    6 marks5.1.3 Gene technologies
    The whole paper ↗
    June 2024 Paper 1, question 35(a): Transcription is the process of producing mRNA using a strand of DNA as a template. The diagram shows a prokaryotic cell producing mature mRNA. Plasma membrane

  11. Q35(b)

    June 2024 · Paper 1

    3 marks5.1.3 Gene technologies
    The whole paper ↗
    June 2024 Paper 1, question 35(b): RNA interference (RNAi) is used by many organisms to control genes. Two forms of RNA, microRNA (miRNA) and small interfering RNA (siRNA), are involved in the di

  12. Q1(b)

    June 2024 · Paper 3

    6 marks2.1.4 Nucleic acids5.1.3 Gene technologies
    The whole paper ↗
    June 2024 Paper 3, question 1(b): (b)* Different methods are used to study DNA. Outline the methods you would use to: • purify DNA from plant tissue by precipitation • separate the DNA into frag

  13. Q2(e)

    June 2024 · Paper 3

    2 marks5.1.3 Gene technologies
    The whole paper ↗
    June 2024 Paper 3, question 2(e): In 2022, the government of the UK announced a rare diseases action plan, which outlined ways to improve the diagnosis and treatment of rare diseases. The use of

  14. Q22

    June 2023 · Paper 1

    1 mark5.1.3 Gene technologies
    The whole paper ↗
    June 2023 Paper 1, question 22: Which statement about post-transcriptional modification of mRNA is correct? A Both introns and exons code for amino acid sequences. B Introns are found in the m

  15. Q23

    June 2023 · Paper 1

    1 mark5.1.3 Gene technologies
    The whole paper ↗
    June 2023 Paper 1, question 23: The sentences below are about the principles of RNA interference (RNAi). 1 In RNAi, gene expression is and protein synthesis is blocked. It involves 2 3 molecul

  16. Q18

    June 2022 · Paper 1

    1 mark5.1.3 Gene technologies
    The whole paper ↗
    June 2022 Paper 1, question 18: DNA ligase is an enzyme used in genetic engineering to produce human proteins from bacterial cells. Which of the statements about DNA ligase is/are correct? 1 I

  17. Q3(a)(i)

    June 2022 · Paper 2

    3 marks5.1.3 Gene technologies
    The whole paper ↗
    June 2022 Paper 2, question 3(a)(i): Describe a procedure you could use to compare the lengths of the VNTRs in two samples of DNA. [3]

  18. Q3(a)(ii)

    June 2022 · Paper 2

    2 marks5.1.3 Gene technologies
    The whole paper ↗
    June 2022 Paper 2, question 3(a)(ii): Explain why forensic analysis uses VNTRs from different chromosomes or from loci that are far apart on the same chromosome. [2]

  19. Q3(a)(iii)

    June 2022 · Paper 2

    2 marks5.1.3 Gene technologies
    The whole paper ↗
    June 2022 Paper 2, question 3(a)(iii): More recent forensic methods use shorter tandem repeats, typically 3 – 5 bases long. These are called short tandem repeats (STRs). STRs of different lengths at

  20. Q3(b)(i)

    June 2022 · Paper 2

    1 mark5.1.3 Gene technologies
    The whole paper ↗
    June 2022 Paper 2, question 3(b)(i): State the meaning of the term haplotype. [1]
All 48 questions on Gene technologies, as a list
  1. June 2025, Paper 3, Q4(b)(i) (2 marks): Complete the table to show the temperatures used in the three stages of a PCR cycle and the processes that occur at each temperature. Temperature (°C) Process S
  2. June 2025, Paper 3, Q4(b)(ii) (2 marks): In theory, the number of DNA molecules can increase exponentially during PCR. Calculate the theoretical maximum number of DNA molecules that could be present af
  3. June 2025, Paper 3, Q4(b)(iii) (1 mark): Suggest one reason why the theoretical maximum number of DNA molecules might not be achieved. [1]
  4. June 2025, Paper 3, Q4(b)(iv) (1 mark): A version of PCR known as quantitative PCR (qPCR) is used to detect alleles that are associated with an increased risk of cancer. qPCR involves: • extracting mR
  5. June 2025, Paper 3, Q4(b)(v) (2 marks): The diagram shows a fluorescent probe used in qPCR. Before the probe has bound to cDNA After the action of Taq DNA polymerase Quencher (molecule that Fluorescen
  6. June 2025, Paper 3, Q4(c)(i) (2 marks): Samples containing DNA fragments are placed in the loading wells of the electrophoresis box before beginning electrophoresis. State one other substance that sho
  7. June 2025, Paper 3, Q4(c)(ii) (2 marks): State and explain the purpose of the DNA fragments in lane 1 in the diagram. [2]
  8. June 2025, Paper 3, Q4(c)(iii) (2 marks): State the lane numbers that indicate: • a genotype that is homozygous for the normal CYP17 allele • a genotype that is homozygous for the mutant CYP17 allele. •
  9. June 2024, Paper 1, Q23 (1 mark): Knockout mice are developed as model organisms for studying conditions such as diabetes. Which statement about the features of knockout mice is correct? A An ar
  10. June 2024, Paper 1, Q35(a) (6 marks): Transcription is the process of producing mRNA using a strand of DNA as a template. The diagram shows a prokaryotic cell producing mature mRNA. Plasma membrane
  11. June 2024, Paper 1, Q35(b) (3 marks): RNA interference (RNAi) is used by many organisms to control genes. Two forms of RNA, microRNA (miRNA) and small interfering RNA (siRNA), are involved in the di
  12. June 2024, Paper 3, Q1(b) (6 marks): (b)* Different methods are used to study DNA. Outline the methods you would use to: • purify DNA from plant tissue by precipitation • separate the DNA into frag
  13. June 2024, Paper 3, Q2(e) (2 marks): In 2022, the government of the UK announced a rare diseases action plan, which outlined ways to improve the diagnosis and treatment of rare diseases. The use of
  14. June 2023, Paper 1, Q22 (1 mark): Which statement about post-transcriptional modification of mRNA is correct? A Both introns and exons code for amino acid sequences. B Introns are found in the m
  15. June 2023, Paper 1, Q23 (1 mark): The sentences below are about the principles of RNA interference (RNAi). 1 In RNAi, gene expression is and protein synthesis is blocked. It involves 2 3 molecul
  16. June 2022, Paper 1, Q18 (1 mark): DNA ligase is an enzyme used in genetic engineering to produce human proteins from bacterial cells. Which of the statements about DNA ligase is/are correct? 1 I
  17. June 2022, Paper 2, Q3(a)(i) (3 marks): Describe a procedure you could use to compare the lengths of the VNTRs in two samples of DNA. [3]
  18. June 2022, Paper 2, Q3(a)(ii) (2 marks): Explain why forensic analysis uses VNTRs from different chromosomes or from loci that are far apart on the same chromosome. [2]
  19. June 2022, Paper 2, Q3(a)(iii) (2 marks): More recent forensic methods use shorter tandem repeats, typically 3 – 5 bases long. These are called short tandem repeats (STRs). STRs of different lengths at
  20. June 2022, Paper 2, Q3(b)(i) (1 mark): State the meaning of the term haplotype. [1]
  21. June 2022, Paper 2, Q3(b)(ii) (4 marks): In this study, DNA from patients with hypothyroidism was sequenced. 52 patients from 41 families had mutations in the Tg gene. Table 3.2 shows the results of ha
  22. June 2022, Paper 2, Q5(d)(i) (2 marks): Suggest how the Ad-IGF-1 could safely deliver the IGF-1 gene into cells in the placenta. [2]
  23. June 2022, Paper 2, Q5(d)(ii) (2 marks): Explain the purpose of Group A and Group C in the study. Group A Group C [2]
  24. June 2022, Paper 2, Q5(d)(iii) (4 marks): The fetuses were allowed to grow and were weighed immediately after birth. The results are shown in Fig. 5.2. 60- 40- Fetal weight (g) 20- A D Group Fig. 5.2 St
  25. November 2021, Paper 1, Q20 (1 mark): Somatic cell gene therapy has been used for treating people with mitochondrial myopathy, a disease of the muscles caused by damage to the mitochondria. Which of
  26. November 2021, Paper 1, Q21 (1 mark): Taq polymerase is an enzyme used during the polymerase chain reaction (PCR). • At optimum temperature, Taq can replicate DNA at a rate of 150 nucleotides per se
  27. November 2021, Paper 1, Q35(c) (3 marks): Avidin is a glycoprotein found in the whites of bird and reptile eggs. It has been investigated as an alternative insecticide for crop plants such as wheat. In
  28. November 2020, Paper 1, Q8 (1 mark): Which of the following statements is/are true of variable number tandem repeats (VNTRs) and single nucleotide polymorphisms (SNPs)? 1: Both VNTRs and SNPs are o
  29. November 2020, Paper 1, Q21 (1 mark): The diagrams A to D represent different setups of an agarose gel electrophoresis experiment. Each diagram shows an agarose gel and the positive and negative ele
  30. November 2020, Paper 2, Q1(c)(i) (3 marks): In PCR, the DNA is placed in a buffered solution in a thermocycler. State the three other components that are placed in the buffered solution in PCR. 1. 2. 3. [
  31. November 2020, Paper 2, Q1(c)(ii) (2 marks): A sample contained 1500 molecules of mtDNA. Calculate the number of mtDNA molecules you would expect after 15 cycles of PCR. Express your answer as a log10 valu
  32. November 2020, Paper 2, Q1(c)(iii) (4 marks): Place the events, A to G, in the correct order in the boxes below to describe the process of gel electrophoresis. The first one is done for you. A DNA fragments
  33. June 2019, Paper 1, Q35(a) (1 mark): Define the term palindrome in the context of DNA. [1]
  34. June 2019, Paper 1, Q35(b)(i) (1 mark): Cas9 is an endonuclease enzyme because it cuts within a nucleotide sequence. Name another type of bacterial endonuclease enzyme. [1]
  35. June 2019, Paper 1, Q35(b)(ii) (2 marks): State one similarity and one difference between Cas9 and the type of enzyme in (b)(i). similarity difference [2]
  36. June 2019, Paper 1, Q35(c) (4 marks): CRISPR has been adapted into a laboratory tool for genetic modification in eukaryotic cells. Using purified Cas9 protein and artificially-synthesised guide RNA
  37. June 2019, Paper 1, Q35(d) (3 marks): Using the most appropriate word(s), complete the sentences below about the production of mature mRNA. A molecule of pre-mRNA contains sequences that code for am
  38. June 2018, Paper 1, Q3 (1 mark): Which of the statements, A to D, is true of single nucleotide polymorphisms (SNPs)? A All SNPs have four possible variations. B Genetic recombination can genera
  39. June 2018, Paper 1, Q22 (1 mark): The polymerase chain reaction (PCR) involves a repeating sequence of temperature changes. Which of the options, A to D, occurs at a temperature of 72 °C? A anne
  40. June 2018, Paper 2, Q2(d)(ii) (2 marks): Alleles of the miRNA 156 gene regulate a group of transcription factors in alfalfa. These transcription factors activate or inhibit promoters that control genes
  41. June 2018, Paper 2, Q2(d)(iii) (2 marks): Scientists have made a plasmid that produces more of the miRNA 156 gene product than normal and want to use this to develop a drought-resistant alfalfa plant. E
  42. June 2018, Paper 3, Q1(c)(i) (3 marks): In response to infection by Rhizobium, bean plant nodule cells produce protein called leghaemoglobin. Researchers wanted to find out more about three genes that
  43. June 2018, Paper 3, Q1(c)(ii) (3 marks): Describe how miRNA inhibits the mRNA of the treated plants. [3]
  44. June 2018, Paper 3, Q1(c)(iii) (1 mark): Explain why the researchers chose miRNA rather than siRNA (small interfering RNA) to inhibit the transcription of the leghaemoglobin genes. [1]
  45. June 2017, Paper 1, Q25 (1 mark): A gene mutation causes part of a DNA sequence to change from TAC to TAA. TAA is a stop codon. Which of the statements, A to D, is a correct explanation of why t
  46. June 2017, Paper 1, Q32(c) (6 marks): This question is about the hormonal control of blood glucose concentration in health and disease. (c)* Some patients with diabetes are treated with regular insu
  47. June 2017, Paper 2, Q1(c) (6 marks): This question is based on the Advance Notice article TURBOCHARGED PHOTOSYNTHESIS?, which is an insert. (c)* Evaluate the risks and benefits of growing supercrop
  48. June 2017, Paper 2, Q3(c)(i) (2 marks): Single nucleotide polymorphisms (SNPs) have been detected in the genes coding for several types of VGSC. It is thought that these SNPs might alter the response

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