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Photosynthesis: OCR A‑Level Biology A questions

Every OCR A-Level Biology A exam question on 5.2.1 Photosynthesis, 2016–2025, with its mark scheme and examiner’s report.

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1,984 questions

  1. Q14

    June 2025 · Paper 1

    1 mark5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 14: Which of the statements about the effect of reducing light intensity is/are correct? 1 The amount of glucose produced will be reduced. 2 The concentration of GP

  2. Q15

    June 2025 · Paper 1

    1 mark5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 15: Which of the statements about the effect of reducing carbon dioxide concentration is/are correct? 1 The amount of glucose produced will be increased. 2 The conc

  3. Q16(a)(i)

    June 2025 · Paper 1

    4 marks5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 16(a)(i): Identify the components labelled A and B and describe how they are adapted for their function. Component A Adaptation Component B Adaptation [4]

  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. Q16(b)(i)

    June 2025 · Paper 1

    3 marks5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 16(b)(i): Calculate the R f for the most soluble pigment. Give your answer to 2 significant figures. Distance travelled = mm Rf = [3]

  6. Q16(b)(ii)

    June 2025 · Paper 1

    2 marks5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 16(b)(ii): The student noticed that the spots were very faint and thought that there might be other pigments present in the mixture that were too faint to be seen. Describ

  7. Q16(b)(iii)

    June 2025 · Paper 1

    1 mark5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 16(b)(iii): Describe how the student could use the same equipment but increase the accuracy of the calculated Rf value. [1]

  8. Q16(b)(iv)

    June 2025 · Paper 1

    1 mark5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 16(b)(iv): The student was not able to identify any of the pigments using Rf values from a data book. Suggest an explanation for this. [1]

  9. Q16(b)(v)

    June 2025 · Paper 1

    2 marks5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 16(b)(v): Describe how the student could use TLC to identify the pigments present in the mixture without calculating Rf values. [2]

  10. Q19(a)(i)

    June 2025 · Paper 1

    2 marks5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 19(a)(i): State two variables that the student should keep constant during this experiment. 1 2 [2]

  11. Q19(a)(ii)

    June 2025 · Paper 1

    2 marks5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 19(a)(ii): The student places the bottles at different distances from a light source. There are four replicates at each distance. The student’s results are shown in the ta

  12. Q19(a)(iii)

    June 2025 · Paper 1

    2 marks5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 19(a)(iii): Outline an improvement to the method that the student could use to get a more accurate measure of the rate of photosynthesis. [2]

  13. Q19(b)(i)

    June 2025 · Paper 1

    2 marks5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 19(b)(i): Explain why it would not be possible to use the hydrogencarbonate indicator method to investigate the effect of CO2 concentration. [2]

  14. Q19(b)(ii)

    June 2025 · Paper 1

    2 marks5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 19(b)(ii): Suggest how the student could modify the method so the effect of CO2 concentration on the rate of photosynthesis could be measured. [2]

  15. Q19(c)(i)

    June 2025 · Paper 1

    2 marks5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 19(c)(i): Explain the evidence from the graph that shows that CO2 concentration is a limiting factor in these experiments. [2]

  16. Q19(c)(ii)

    June 2025 · Paper 1

    2 marks5.2.1 Photosynthesis
    The whole paper ↗
    June 2025 Paper 1, question 19(c)(ii): A student looked at the graph and concluded that CO2 concentration has a greater effect on the rate of photosynthesis than temperature. Use your knowledge of Q1

  17. Q13

    June 2024 · Paper 1

    1 mark5.2.1 Photosynthesis
    The whole paper ↗
    June 2024 Paper 1, question 13: Which of the statements about the effect of light intensity on the concentrations of GP, RuBP and TP is/are correct? 1 At low light intensity, less GP is conver

  18. Q14

    June 2024 · Paper 1

    1 mark5.2.1 Photosynthesis
    The whole paper ↗
    June 2024 Paper 1, question 14: Which of the statements about factors affecting the rate of photosynthesis is/are correct? 1 Lack of water is not usually a limiting factor, although it does ca

  19. Q17(a)(i)

    June 2024 · Paper 1

    2 marks5.2.1 Photosynthesis
    The whole paper ↗
    June 2024 Paper 1, question 17(a)(i): Identify the molecules labelled X, Y and Z in Fig. 17.1. X Y Z [2]

  20. Q17(a)(ii)

    June 2024 · Paper 1

    3 marks5.2.1 Photosynthesis
    The whole paper ↗
    June 2024 Paper 1, question 17(a)(ii): Use the information in Fig. 17.1 to explain how plants are able to survive in a sealed glass container, such as a terrarium or bottle garden, for many months or
All 76 questions on Photosynthesis, as a list
  1. June 2025, Paper 1, Q14 (1 mark): Which of the statements about the effect of reducing light intensity is/are correct? 1 The amount of glucose produced will be reduced. 2 The concentration of GP
  2. June 2025, Paper 1, Q15 (1 mark): Which of the statements about the effect of reducing carbon dioxide concentration is/are correct? 1 The amount of glucose produced will be increased. 2 The conc
  3. June 2025, Paper 1, Q16(a)(i) (4 marks): Identify the components labelled A and B and describe how they are adapted for their function. Component A Adaptation Component B Adaptation [4]
  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, Q16(b)(i) (3 marks): Calculate the R f for the most soluble pigment. Give your answer to 2 significant figures. Distance travelled = mm Rf = [3]
  6. June 2025, Paper 1, Q16(b)(ii) (2 marks): The student noticed that the spots were very faint and thought that there might be other pigments present in the mixture that were too faint to be seen. Describ
  7. June 2025, Paper 1, Q16(b)(iii) (1 mark): Describe how the student could use the same equipment but increase the accuracy of the calculated Rf value. [1]
  8. June 2025, Paper 1, Q16(b)(iv) (1 mark): The student was not able to identify any of the pigments using Rf values from a data book. Suggest an explanation for this. [1]
  9. June 2025, Paper 1, Q16(b)(v) (2 marks): Describe how the student could use TLC to identify the pigments present in the mixture without calculating Rf values. [2]
  10. June 2025, Paper 1, Q19(a)(i) (2 marks): State two variables that the student should keep constant during this experiment. 1 2 [2]
  11. June 2025, Paper 1, Q19(a)(ii) (2 marks): The student places the bottles at different distances from a light source. There are four replicates at each distance. The student’s results are shown in the ta
  12. June 2025, Paper 1, Q19(a)(iii) (2 marks): Outline an improvement to the method that the student could use to get a more accurate measure of the rate of photosynthesis. [2]
  13. June 2025, Paper 1, Q19(b)(i) (2 marks): Explain why it would not be possible to use the hydrogencarbonate indicator method to investigate the effect of CO2 concentration. [2]
  14. June 2025, Paper 1, Q19(b)(ii) (2 marks): Suggest how the student could modify the method so the effect of CO2 concentration on the rate of photosynthesis could be measured. [2]
  15. June 2025, Paper 1, Q19(c)(i) (2 marks): Explain the evidence from the graph that shows that CO2 concentration is a limiting factor in these experiments. [2]
  16. June 2025, Paper 1, Q19(c)(ii) (2 marks): A student looked at the graph and concluded that CO2 concentration has a greater effect on the rate of photosynthesis than temperature. Use your knowledge of Q1
  17. June 2024, Paper 1, Q13 (1 mark): Which of the statements about the effect of light intensity on the concentrations of GP, RuBP and TP is/are correct? 1 At low light intensity, less GP is conver
  18. June 2024, Paper 1, Q14 (1 mark): Which of the statements about factors affecting the rate of photosynthesis is/are correct? 1 Lack of water is not usually a limiting factor, although it does ca
  19. June 2024, Paper 1, Q17(a)(i) (2 marks): Identify the molecules labelled X, Y and Z in Fig. 17.1. X Y Z [2]
  20. June 2024, Paper 1, Q17(a)(ii) (3 marks): Use the information in Fig. 17.1 to explain how plants are able to survive in a sealed glass container, such as a terrarium or bottle garden, for many months or
  21. June 2024, Paper 1, Q17(b)(i) (1 mark): Chlorophyll a has an absorption peak at 680 nm. Use Fig. 17.2 to estimate the percentage of light absorbed by chlorophyll a that is used in photosynthesis by Po
  22. June 2024, Paper 1, Q17(b)(ii) (3 marks): Explain why the percentage of light used in photosynthesis is higher than your answer to part (i) at wavelengths other than 680 nm. [3]
  23. June 2024, Paper 1, Q17(b)(iii) (2 marks): Porphyra naiadum grows in deep water. Use the data in Fig. 17.2 to suggest how it is able to survive in conditions where other types of algae or plant cannot. [
  24. June 2024, Paper 1, Q17(c)(i) (2 marks): Calvin concluded that GP was the first product of carbon fixation, and that GP was converted into TP. Use the data in Fig. 17.3 to explain how Calvin reached th
  25. June 2024, Paper 1, Q17(c)(ii) (1 mark): State what you can conclude from Fig. 17.3 about what happens to TP. [1]
  26. June 2024, Paper 3, Q4(c)(i) (2 marks): Evidence for chemiosmosis during photosynthesis can be demonstrated by: • isolating chloroplasts from plant cells • placing the chloroplasts in an acidic soluti
  27. June 2024, Paper 3, Q4(c)(ii) (2 marks): André Jagendorf provided evidence for chemiosmosis in an experiment carried out in the 1960s. In his experiment, Jagendorf: • broke open chloroplasts to expose
  28. June 2023, Paper 1, Q8 (1 mark): The diagram shows the absorption spectra of different photosynthetic pigments. Chlorophyll b Carotenoids Absorbance (%) Chlorophyll a 400 500 600 700 Wavelength
  29. 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
  30. June 2023, Paper 3, Q3(a)(i) (1 mark): State one dependent variable in this investigation. [1]
  31. June 2023, Paper 3, Q3(a)(ii) (2 marks): Explain the effect of genetic modification on the rate of CO2 fixation after 150 seconds of low light intensity. [2]
  32. June 2022, Paper 1, Q7 (1 mark): Which option is not a component of a chloroplast? A Cristae B DNA C Ribosome D Thylakoid Your answer [1] 5 The following information is needed to answer questio
  33. June 2022, Paper 1, Q8 (1 mark): One student examined a cross section of a leaf under a light microscope. They counted the number of chloroplasts in each cell in the field of view. Their result
  34. June 2022, Paper 1, Q9 (1 mark): Which option is the correct procedure for statistical analysis of the data collected by the class? A Calculate the mean number of chloroplasts per cell in the h
  35. June 2022, Paper 1, Q14 (1 mark): Which of the statements about the relationship between photosynthesis and aerobic respiration in plants is/are correct? 1 During the day, photosynthesis produce
  36. June 2022, Paper 1, Q22(a) (4 marks): The image is a transmission electron micrograph (TEM) of a chloroplast. F G D E Complete the table using the letters from the TEM which identifies the structure
  37. June 2022, Paper 1, Q22(b) (5 marks): Complete the sentences using the most appropriate terms. Carbon fixation occurs in the Calvin cycle when CO2 combines with the five-carbon molecule . This forms
  38. November 2021, Paper 1, Q19(a)(i) (1 mark): State the name of the final electron acceptor in the light-dependent stage of photosynthesis. [1]
  39. November 2021, Paper 1, Q19(a)(ii) (2 marks): DCPIP is reduced in the Hill reaction. Suggest and explain the function of DCPIP in the Hill reaction. [2]
  40. November 2021, Paper 1, Q19(a)(iii) (4 marks): Using the results shown in the table, explain what can be concluded from each tube, or pair of tubes, about the light-dependent stage of photosynthesis. Tube A
  41. November 2021, Paper 1, Q19(a)(iv) (2 marks): The student knew that it was important to use sucrose solution when homogenising the leaves. Explain why it was important that the pellet was suspended in buffe
  42. November 2021, Paper 1, Q19(a)(v) (4 marks): Suggest and explain two improvements that would increase the validity of the method. Improvement 1 Explanation Improvement 2 Explanation [4]
  43. November 2021, Paper 1, Q19(b)(i) (1 mark): Suggest one other reason why the plants in a sealed terrarium continue to grow. [1]
  44. November 2021, Paper 3, Q5(b) (2 marks): Light intensity is one factor that affects the rate of photosynthesis. Fig. 5.1 shows how the rate of photosynthesis varies with light intensity in two plants:
  45. November 2021, Paper 3, Q5(c)(i) (3 marks): The students investigated the relationship between the water content of soils and mean rate of photosynthesis for the two plants. Using the values in Table 5.2,
  46. November 2021, Paper 3, Q5(c)(ii) (1 mark): Use Table 5.3 to decide what the students can conclude from the rs value you calculated in part (i). [1]
  47. November 2021, Paper 3, Q5(c)(iii) (1 mark): The students calculated the rs value for water content and rate of photosynthesis in Calotropis procera as 0.714. Use Table 5.3 to decide what the students can
  48. November 2021, Paper 3, Q5(d)(i) (1 mark): The cyanobacterium Acaryochloris marina lives in an aquatic habitat with many aquatic plant species. Acaryochloris marina has a high concentration of chlorophyl
  49. November 2021, Paper 3, Q5(d)(ii) (1 mark): Diatoms are unicellular photosynthetic eukaryotes. Diatoms contain high concentrations of the pigment fucoxanthin. Fig. 5.3 shows a chromatogram with three pigm
  50. November 2020, Paper 1, Q17(a)(i) (3 marks): Calculate the Rf value for spot 3 and use this to identify the pigment that spot 3 represents. Rf = pigment = [3]
  51. November 2020, Paper 1, Q17(a)(ii) (1 mark): Predict the colour of spot 4. [1]
  52. November 2020, Paper 1, Q17(a)(iii) (2 marks): The solvent used for the separation was non-polar. Identify the spot corresponding to the least polar pigment. Give a reason for your choice. spot reason [2]
  53. November 2020, Paper 1, Q17(b)(i) (2 marks): Explain why the method included the following precautions: Hold the TLC plate carefully by the edges and avoid damaging the surface of the plate. Make sure the
  54. November 2020, Paper 1, Q17(b)(ii) (1 mark): Suggest an advantage of working as quickly as possible in Step 1. [1]
  55. November 2020, Paper 1, Q17(c) (3 marks): Algae are single-celled photosynthetic organisms. An investigation was carried out into the effect of CO2 concentration on the concentrations of ribulose bispho
  56. June 2019, Paper 1, Q14 (1 mark): Cyanobacteria are photosynthetic prokaryotes. A scientist exposed cyanobacteria to light of different colours and intensities and made the following observation
  57. June 2019, Paper 1, Q22(a) (4 marks): Identify the molecules represented by the letters A, B, C and D in Fig. 22.1 A B C D [4]
  58. June 2019, Paper 1, Q22(b)(i) (3 marks): Identify the following variables from the scientist’s method: independent variable dependent variable one control variable [3]
  59. June 2019, Paper 1, Q22(b)(ii) (1 mark): Identify one variable that was not controlled in the scientist’s method. [1]
  60. June 2019, Paper 1, Q22(c) (3 marks): Fig. 22.2 is a graph of the scientist’s results. 22 20 18 10 °C 16 O2 concentration 15 °C (mg dm–3) 14 20 °C 25 °C 12 30 °C 10 0 0 20 40 60 80 100 120 140 160 1
  61. June 2019, Paper 1, Q22(d)(i) (2 marks): Explain why this is both an accurate and an inaccurate way to describe the light- independent stage. [2]
  62. June 2019, Paper 1, Q22(d)(ii) (1 mark): Name the enzyme responsible for fixing CO2 in the light-independent stage. [1]
  63. 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
  64. June 2018, Paper 1, Q17(a)(i) (4 marks): Outline the importance of photosynthetic pigments in photosynthesis. [4]
  65. June 2018, Paper 1, Q17(a)(ii) (1 mark): The wavelengths of light absorbed by chlorophyll c are different from those wavelengths absorbed by chlorophyll a and chlorophyll b. Suggest why Chromista need
  66. June 2018, Paper 1, Q17(b) (2 marks): Fig. 17.1 is a diagram of the chloroplast found in a Chromista cell. thylakoids stacked external membrane in threes DNA Fig. 17.1 Outline the structural differe
  67. June 2018, Paper 1, Q22(a)(ii) (2 marks): 1700 lux is a typical light intensity on a cloudy day in the UK. Calculate the percentage increase in gas production between 1700 and 2000 lux. Show your workin
  68. June 2018, Paper 1, Q22(a)(iii) (1 mark): Suggest why soda-lime was not placed in the respirometer with the seedlings grown in the light. [1]
  69. June 2018, Paper 1, Q22(b) (2 marks): The scientist made the following claim: These results suggest that, in maize seedlings, the rate of photosynthesis only exceeds the rate of respiration when the
  70. June 2018, Paper 3, Q3(a)(i) (2 marks): Identify the anomalous result in Table 3 and explain how this result could be confirmed as an anomaly. [2]
  71. June 2018, Paper 3, Q3(a)(ii) (6 marks): Temperature and light intensity are two factors that affect the rate of photosynthesis. A student investigated how temperature and light intensity affected the
  72. June 2018, Paper 3, Q3(b) (2 marks): Photosynthesis occurs in two stages: the light-dependent stage and the light-independent stage. The light-independent stage is affected by temperature more than
  73. June 2017, Paper 1, Q2 (1 mark): Which of the images, A to D, correctly summarises photosynthesis? A B reduced reduced light light light light NAD NAD independent dependent dependent independen
  74. June 2017, Paper 1, Q8 (1 mark): RuBisCO is an enzyme that fixes carbon dioxide in photosynthesis. In some conditions, RuBisCO also carries out oxygen fixation. The graph below shows how the ca
  75. June 2017, Paper 1, Q18(a) (2 marks): Light intensity, carbon dioxide concentration and temperature are all limiting factors in photosynthesis. Explain what is meant by a limiting factor. [2] Questi
  76. June 2017, Paper 3, Q1(b)(ii) (2 marks): State the precise location of photosynthetic pigments in a chloroplast. [2]

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