plumiFactors affecting photosynthesis: OCR A‑Level Biology A questions
OCR A-Level Biology A past-paper questions on 5.2.1.5 Factors affecting photosynthesis, 2016–2025, with mark schemes and examiner’s reports where available.
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All 27 questions on Factors affecting photosynthesis, as a list
- 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
- 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
- June 2025, Paper 1, Q19(a)(i) (2 marks): State two variables that the student should keep constant during this experiment. 1 2 [2]
- 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
- 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]
- 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]
- 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]
- 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]
- 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
- 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
- June 2023, Paper 3, Q3(a)(i) (1 mark): State one dependent variable in this investigation. [1]
- 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]
- 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:
- 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,
- 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]
- 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
- 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
- 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]
- June 2019, Paper 1, Q22(b)(ii) (1 mark): Identify one variable that was not controlled in the scientist’s method. [1]
- 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
- 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
- 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]
- 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
- 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]
- 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
- 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
- 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
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