Skip to content
Try on iPad

Respiration: OCR A‑Level Biology A questions

Every OCR A-Level Biology A exam question on 5.2.2 Respiration, 2016–2025, with its mark scheme and examiner’s report.

Find questions1,984
Calculations

1,984 questions

  1. Q9

    June 2025 · Paper 1

    1 mark5.2.2 Respiration
    The whole paper ↗
    June 2025 Paper 1, question 9: A scientist measures the oxygen uptake and carbon dioxide output of an athlete on an exercise bike at increasing work rates. The results are shown in the graph.

  2. Q12

    June 2025 · Paper 1

    1 mark5.2.2 Respiration
    The whole paper ↗
    June 2025 Paper 1, question 12: What is the function of the link reaction in aerobic respiration? A It converts acetate produced in glycolysis to pyruvate. B It converts pyruvate to oxaloaceta

  3. Q13

    June 2025 · Paper 1

    1 mark5.2.2 Respiration
    The whole paper ↗
    June 2025 Paper 1, question 13: Which statement does not describe the Krebs cycle? A It combines an acetyl group with citrate to form oxaloacetate. B It is a source of ATP produced by substrat

  4. Q16(a)(ii)

    June 2025 · Paper 1

    2 marks5.2.1 Photosynthesis5.2.2 Respiration
    The whole paper ↗
    June 2025 Paper 1, question 16(a)(ii): Identify one similarity and one difference between the structures of chloroplasts and the structures of mitochondria. Similarity Difference [2]

  5. Q17(a)(i)

    June 2025 · Paper 1

    1 mark5.2.2 Respiration
    The whole paper ↗
    June 2025 Paper 1, question 17(a)(i): State the type of reaction that is catalysed by PFK. [1]

  6. Q17(a)(v)

    June 2025 · Paper 1

    2 marks5.2.2 Respiration2.1.4 Enzymes
    The whole paper ↗
    June 2025 Paper 1, question 17(a)(v): ATP is converted to ADP and then AMP (adenosine monophosphate) when ATP provides energy for processes in the cell. AMP reverses the inhibition of PFK by ATP. Us

  7. Q17(c)(i)

    June 2025 · Paper 1

    1 mark5.2.2 Respiration
    The whole paper ↗
    June 2025 Paper 1, question 17(c)(i): State the name of the type of reaction in aerobic respiration that produces CO2. [1]

  8. Q17(c)(ii)

    June 2025 · Paper 1

    2 marks5.2.2 Respiration
    The whole paper ↗
    June 2025 Paper 1, question 17(c)(ii): State the names of the two stages in respiration where CO2 production occurs. 1 2 [2]

  9. Q17(c)(iii)

    June 2025 · Paper 1

    2 marks5.2.2 Respiration
    The whole paper ↗
    June 2025 Paper 1, question 17(c)(iii): Respiration of glucose involves a series of oxidation reactions. Explain how oxidation occurs in glycolysis. [2]

  10. Q15

    June 2024 · Paper 1

    1 mark5.2.2 Respiration
    The whole paper ↗
    June 2024 Paper 1, question 15: Which option about the relative energy values of different foods is not correct? A Carbohydrates have lower energy values because they have a higher oxygen cont

  11. Q20(c)(i)

    June 2024 · Paper 1

    1 mark5.2.2 Respiration
    The whole paper ↗
    June 2024 Paper 1, question 20(c)(i): State the two measurements that you would need to make during the experiment to calculate RQ. 1 2 [1]

  12. Q20(c)(ii)

    June 2024 · Paper 1

    3 marks5.2.2 Respiration
    The whole paper ↗
    June 2024 Paper 1, question 20(c)(ii): Explain what Fig. 20.3 shows about the respiratory substrate(s) used at different intensities of exercise. [3]

  13. Q4(b)

    June 2024 · Paper 3

    1 mark5.2.2 Respiration
    The whole paper ↗
    June 2024 Paper 3, question 4(b): Outline why cellular respiration is necessary in cells that are carrying out DNA replication. [1]

  14. Q9

    June 2023 · Paper 1

    1 mark5.2.1 Photosynthesis5.2.2 Respiration
    The whole paper ↗
    June 2023 Paper 1, question 9: The diagram shows some of the reactions that take place in a leaf cell in a flowering plant. Disaccharides and polysaccharides Glucose Hexose phosphate Hexose b

  15. Q19(d)

    June 2023 · Paper 1

    2 marks5.2.2 Respiration
    The whole paper ↗
    June 2023 Paper 1, question 19(d): An adult was advised to change their diet to reduce their body mass before undergoing surgery. Over a period of several weeks their body mass reduced by 1 kg. S

  16. Q2(c)(i)

    June 2023 · Paper 3

    2 marks5.2.2 Respiration
    The whole paper ↗
    June 2023 Paper 3, question 2(c)(i): A mitochondrion is shown in Fig. 2.3. Label Fig. 2.3 to show the locations where FAD gains H atoms and where FAD releases H atoms during respiration. • Use the

  17. Q2(c)(ii)

    June 2023 · Paper 3

    2 marks5.2.2 Respiration
    The whole paper ↗
    June 2023 Paper 3, question 2(c)(ii): The table lists features that are correct for FAD, NAD, both or neither. Complete the table by adding a tick (✓) to a box where the feature is correct and a cro

  18. Q2(c)(iii)

    June 2023 · Paper 3

    1 mark5.2.2 Respiration
    The whole paper ↗
    June 2023 Paper 3, question 2(c)(iii): ATP is produced in respiration. Some of these molecules of ATP are used to release energy for processes in respiration. For example, ATP is used in the early st

  19. Q5(a)(i)

    June 2023 · Paper 3

    2 marks5.2.2 Respiration
    The whole paper ↗
    June 2023 Paper 3, question 5(a)(i): Compare CO2 production when the substrate is glucose and CO2 production when the substrate is maltose. [2]

  20. Q5(a)(ii)

    June 2023 · Paper 3

    2 marks5.2.2 Respiration
    The whole paper ↗
    June 2023 Paper 3, question 5(a)(ii): The student wrote a note: ‘The CO2 production with fructose is approximately the same as the CO2 production with sucrose’. Explain whether you agree with the st
All 71 questions on Respiration, as a list
  1. June 2025, Paper 1, Q9 (1 mark): A scientist measures the oxygen uptake and carbon dioxide output of an athlete on an exercise bike at increasing work rates. The results are shown in the graph.
  2. June 2025, Paper 1, Q12 (1 mark): What is the function of the link reaction in aerobic respiration? A It converts acetate produced in glycolysis to pyruvate. B It converts pyruvate to oxaloaceta
  3. June 2025, Paper 1, Q13 (1 mark): Which statement does not describe the Krebs cycle? A It combines an acetyl group with citrate to form oxaloacetate. B It is a source of ATP produced by substrat
  4. June 2025, Paper 1, Q16(a)(ii) (2 marks): Identify one similarity and one difference between the structures of chloroplasts and the structures of mitochondria. Similarity Difference [2]
  5. June 2025, Paper 1, Q17(a)(i) (1 mark): State the type of reaction that is catalysed by PFK. [1]
  6. June 2025, Paper 1, Q17(a)(v) (2 marks): ATP is converted to ADP and then AMP (adenosine monophosphate) when ATP provides energy for processes in the cell. AMP reverses the inhibition of PFK by ATP. Us
  7. June 2025, Paper 1, Q17(c)(i) (1 mark): State the name of the type of reaction in aerobic respiration that produces CO2. [1]
  8. June 2025, Paper 1, Q17(c)(ii) (2 marks): State the names of the two stages in respiration where CO2 production occurs. 1 2 [2]
  9. June 2025, Paper 1, Q17(c)(iii) (2 marks): Respiration of glucose involves a series of oxidation reactions. Explain how oxidation occurs in glycolysis. [2]
  10. June 2024, Paper 1, Q15 (1 mark): Which option about the relative energy values of different foods is not correct? A Carbohydrates have lower energy values because they have a higher oxygen cont
  11. June 2024, Paper 1, Q20(c)(i) (1 mark): State the two measurements that you would need to make during the experiment to calculate RQ. 1 2 [1]
  12. June 2024, Paper 1, Q20(c)(ii) (3 marks): Explain what Fig. 20.3 shows about the respiratory substrate(s) used at different intensities of exercise. [3]
  13. June 2024, Paper 3, Q4(b) (1 mark): Outline why cellular respiration is necessary in cells that are carrying out DNA replication. [1]
  14. June 2023, Paper 1, Q9 (1 mark): The diagram shows some of the reactions that take place in a leaf cell in a flowering plant. Disaccharides and polysaccharides Glucose Hexose phosphate Hexose b
  15. June 2023, Paper 1, Q19(d) (2 marks): An adult was advised to change their diet to reduce their body mass before undergoing surgery. Over a period of several weeks their body mass reduced by 1 kg. S
  16. June 2023, Paper 3, Q2(c)(i) (2 marks): A mitochondrion is shown in Fig. 2.3. Label Fig. 2.3 to show the locations where FAD gains H atoms and where FAD releases H atoms during respiration. • Use the
  17. June 2023, Paper 3, Q2(c)(ii) (2 marks): The table lists features that are correct for FAD, NAD, both or neither. Complete the table by adding a tick (✓) to a box where the feature is correct and a cro
  18. June 2023, Paper 3, Q2(c)(iii) (1 mark): ATP is produced in respiration. Some of these molecules of ATP are used to release energy for processes in respiration. For example, ATP is used in the early st
  19. June 2023, Paper 3, Q5(a)(i) (2 marks): Compare CO2 production when the substrate is glucose and CO2 production when the substrate is maltose. [2]
  20. June 2023, Paper 3, Q5(a)(ii) (2 marks): The student wrote a note: ‘The CO2 production with fructose is approximately the same as the CO2 production with sucrose’. Explain whether you agree with the st
  21. June 2023, Paper 3, Q5(b)(i) (2 marks): The student uses glucose as the respiratory substrate in their experiment. The student produces a 0.01 mol dm–3 glucose solution for each yeast population. This
  22. June 2023, Paper 3, Q5(b)(ii) (3 marks): Complete the sentences using appropriate words or phrases. This is the method that the student uses in their experiment: • To avoid contamination, place the yea
  23. June 2022, Paper 1, Q3 (1 mark): Kendal Mint Cake is made from sugar, flavoured with peppermint, and was famously taken on the 1953 ascent of Mount Everest. Which statement describes why climbe
  24. June 2022, Paper 1, Q12 (1 mark): Linoleic acid is a fatty acid found in sunflower oil. The equation for oxidation of linoleic acid is: Linoleic acid: C18H32O2 + 25 O2 18 CO2 + 16 H2O What is th
  25. June 2022, Paper 1, Q15 (1 mark): Erythrocytes are formed from bone marrow stem cells. During this process they lose most of their organelles. Which statement about respiration in erythrocytes i
  26. June 2022, Paper 1, Q19(d) (6 marks): (d)* Muscle contraction requires energy in the form of ATP. Describe the different sources of the ATP that is used in muscle contraction during strenuous exerci
  27. June 2022, Paper 1, Q20(a)(i) (2 marks): Suggest two modifications the researcher would need to make to this apparatus to investigate the effect of temperature on the rate of respiration. 1 2 [2]
  28. June 2022, Paper 1, Q20(a)(ii) (1 mark): Suggest one advantage of using a computer to collect data. [1]
  29. June 2022, Paper 1, Q20(a)(iii) (2 marks): A constant flow of water past the oxygen probe allows continuous monitoring of oxygen concentration. Explain one other reason why it is necessary to maintain a
  30. June 2022, Paper 1, Q20(a)(iv) (2 marks): Suggest and explain one other precaution that the scientists should take to ensure that the results obtained using this apparatus are valid. [2]
  31. June 2022, Paper 1, Q20(b)(i) (2 marks): Calculate the Q10 for respiration in the largest fish. Give your answer to 3 significant figures. Q10 = [2]
  32. June 2022, Paper 1, Q20(b)(ii) (4 marks): The scientists concluded that the best temperature for farming of O. insignis was 18 °C. Evaluate their conclusion. [4]
  33. November 2021, Paper 1, Q13 (1 mark): NAD, FAD and Coenzyme A (CoA) are molecules that are involved in cellular respiration. Which of the following statements about these molecules is/are correct? 1
  34. November 2021, Paper 1, Q14 (1 mark): A respirometer, shown below, can be used to investigate respiration. tap capillary U-tube containing coloured liquid A student placed 5 cm3 of potassium hydroxi
  35. November 2021, Paper 3, Q4(b)(i) (4 marks): The table below contains information about three amino acids. Use Fig. 4.1 and Fig. 4.2 and your own knowledge to draw a conclusion about which amino acid is be
  36. November 2021, Paper 3, Q4(b)(ii) (2 marks): Outline the reactions that must occur to convert α-ketoglutaric acid to oxaloacetate in Fig. 4.2. [2]
  37. November 2021, Paper 3, Q4(c) (3 marks): Most ATP is produced in mitochondria by chemiosmosis. Outline how ATP is produced in mitochondria by chemiosmosis. [3]
  38. November 2021, Paper 3, Q4(d) (3 marks): A person’s RQ changes when they exercise. Fig. 4.3 shows how RQ changes with the power a person exerts during exercise. Power, measured in watts (W), increases
  39. November 2020, Paper 1, Q11 (1 mark): Which of the following would be necessary to ensure valid results? 1 Keeping the respirometer in the dark during the experiment. 2 Keeping the respirometer at t
  40. November 2020, Paper 1, Q12 (1 mark): The student investigated two types of seed, pea and sunflower: • pea seeds store mainly starch • sunflower seeds store mainly lipid. Which of the following, A t
  41. November 2020, Paper 1, Q13 (1 mark): Which of the following statements, A to D, describes and explains the relative yield of ATP in anaerobic and aerobic respiration? A Anaerobic respiration produc
  42. November 2020, Paper 1, Q19(a)(ii) (2 marks): Identify the structures labelled M and N in the photomicrograph. M N [2]
  43. November 2020, Paper 1, Q19(b) (2 marks): Describe two ways in which the structure of mitochondrial membranes is related to the function of a mitochondrion. 1 2 [2]
  44. November 2020, Paper 1, Q19(c)(ii) (3 marks): Explain why early eukaryotes were able to grow more quickly than cells that did not possess mitochondria. [3]
  45. November 2020, Paper 1, Q20(a)(i) (2 marks): Describe two precautions the student should take between each experiment to ensure repeatable results. 1 2 [2]
  46. November 2020, Paper 1, Q20(a)(ii) (1 mark): The student’s procedure did not include a negative control. Describe one negative control that the student could have used. [1]
  47. November 2020, Paper 1, Q20(b)(i) (3 marks): Describe how the student could use the graph to calculate the rate of respiration for each type of sugar. [3]
  48. November 2020, Paper 1, Q20(b)(ii) (6 marks): A student investigated the effect of different sugars on the respiration rate in yeast using the following procedure. Prepare a stock solution of yeast containi
  49. June 2019, Paper 3, Q2(d)(i) (2 marks): Suggest why the use of fructose allows naked mole rats to survive without oxygen for a long time. [2]
  50. June 2019, Paper 3, Q2(d)(ii) (1 mark): Suggest one other aspect of the physiology of naked mole rats that explains how they are able to survive without oxygen for a long time. [1]
  51. June 2018, Paper 1, Q11 (1 mark): Which of the following, A to D, is a similarity in the way ATP is made in respiration and photosynthesis? A both involve NAD B both involve substrate level phos
  52. June 2018, Paper 1, Q16(b)(ii) (3 marks): Explain why glucose is required for the contraction of skeletal muscle. [3]
  53. June 2018, Paper 1, Q19(a) (3 marks): Use the data in Table 19.1 to suggest the likely diet of each genus of honeypot ant. Justify your answer. Genus Diet Justification Camponotus mainly carbohydrat
  54. June 2018, Paper 1, Q19(c) (6 marks): Honeypot ants belong to several different genera. Some specialised individuals are used as food storage vessels. These individuals have swollen abdomens that st
  55. June 2018, Paper 1, Q22(a)(i) (3 marks): The diameter of the capillary tubing was 0.1 mm. The volume of a cylinder can be calculated using the following formula: volume of cylinder = πr2l Calculate the
  56. June 2018, Paper 3, Q2(a) (4 marks): Describe the production of ATP by substrate-level phosphorylation in different stages of respiration with reference to the number of ATP molecules produced. [4]
  57. June 2018, Paper 3, Q2(c)(i) (1 mark): Using the information in Fig. 2, calculate the percentage of carbon atoms in the fatty acid that are able to enter the Krebs cycle. Answer = % [1]
  58. June 2018, Paper 3, Q2(c)(ii) (1 mark): The percentage of carbon atoms that a reaction makes available for use in the Krebs cycle can be described as the efficiency of the reaction. Calculate the effi
  59. June 2018, Paper 3, Q2(c)(iii) (1 mark): Fig. 2 shows the role of coenzyme A in beta oxidation. Suggest a role for coenzymes other than coenzyme A in beta oxidation. [1]
  60. June 2017, Paper 1, Q18(b)(i) (3 marks): Summarise the conclusions that can be drawn from these data. [3]
  61. June 2017, Paper 1, Q18(b)(ii) (6 marks): (ii)* Water can fill air spaces in the soil surrounding the roots. This prevents oxygen from reaching root hair cells. Using your knowledge of aerobic and anaer
  62. June 2017, Paper 1, Q19(c)(i) (3 marks): Identify the structures labelled with the following letters: U W Z [3] ATP, FADH2 and hexose 1,6-bisphosphate are three organic products of respiration in sperm
  63. June 2017, Paper 1, Q19(c)(ii) (1 mark): What can be concluded about the difference between the effects of cyanide and fluoride on respiration in sperm? [1] for the next question
  64. June 2017, Paper 1, Q20(a) (3 marks): Using the information in Table 20, calculate the standard deviation for the number of CO2 bubbles produced by A. pullulans in anaerobic conditions. Write the an
  65. June 2017, Paper 1, Q20(b) (2 marks): Fig. 20 is a graph showing the mean values of the data from Table 20. 40 35 30 aerobic conditions 25 anaerobic conditions 20 15 10 5 0 S. cerevisiae C. krusei C
  66. June 2017, Paper 1, Q20(c) (3 marks): Calculate the mean percentage change in CO2 production for S. cerevisiae when moving from anaerobic to aerobic respiration. Give your answer to four significant
  67. June 2017, Paper 1, Q20(d)(i) (2 marks): The student drew the following conclusions: 1 All the yeast I investigated produced more CO2 during aerobic respiration than anaerobic respiration. 2 There is a
  68. June 2017, Paper 1, Q20(d)(ii) (1 mark): The student found the following definitions of errors in a text book: Random errors: mistakes during measurements caused by low-resolution equipment Systematic
  69. June 2017, Paper 3, Q2(b)(i) (3 marks): Suggest and explain what conclusions can be drawn from Fig. 2 about the factors that affected the rate and type of respiration carried out by S. cerevisiae in t
  70. June 2017, Paper 3, Q2(b)(iv) (3 marks): A group of students were designing an experiment to investigate the effect of temperature on the respiration rate of S. cerevisiae. Their planned method include
  71. June 2017, Paper 3, Q2(b)(v) (1 mark): The students used a Student’s t-test to compare the results at 30 °C and 35 °C. They calculated a t value of 2.200. The critical value for p = 0.05 is 2.306. As

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? Every OCR A-Level Biology A paper, or our free OCR-style practice pack.

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