Photosynthesis: past paper questions
Real questions on photosynthesis
The newest 20 of 165 written questions, plus 3 multiple-choice. Open one to see it on the real paper.
- 9700/22 · October/November 2025 · Q5a[2]
Fig. 5.1 is a diagram of a cross section through the leaf of a herbaceous dicotyledonous mesophyte. Complete Fig. 5.1 by naming structure A and tissue layer B. A upper epidermis palisade mesophyll vein B intercellular air space lower epidermis
See it on the paper → - 9700/22 · October/November 2025 · Q5b[3]
In xerophytes, some of the structural features shown in Fig. 5.1 are modified as adaptations for surviving conditions of water stress. Complete Table 5.1 to show how the structural feature listed may be modified in the leaf of a xerophyte. Each feature should have a different example of a modification. Table 5.1 struct...
See it on the paper → - 9700/42 · October/November 2025 · Q9a(i)[2]
Explain what is meant by an absorption spectrum and an action spectrum.
See it on the paper → - 9700/42 · October/November 2025 · Q9a(ii)[3]
Suggest and explain why the curve shown in Fig. 9.1 for the absorption spectrum is different from the curve for the action spectrum for wavelengths of light between 450 nm and 550 nm.
See it on the paper → - 9700/42 · October/November 2025 · Q9b(i)[4]
With reference to Fig. 9.2, describe and explain the effect of temperature on the rate of photosynthesis for K. procumbens.
See it on the paper → - 9700/42 · October/November 2025 · Q9b(ii)[2]
The rate of photosynthesis in this investigation was obtained by measuring the uptake of carbon dioxide from the atmosphere. It did not take into account the use of carbon dioxide produced by respiration. Using Fig. 9.2, calculate the rate of photosynthesis at 20 °C when the carbon dioxide produced by respiration is ta...
See it on the paper → - 9700/51 · October/November 2025 · Q1a[1]
Identify the independent variable in this investigation.
See it on the paper → - 9700/51 · October/November 2025 · Q1b(i)[2]
State the volumes that the student used to carry out the dilution to produce 500 cm 3 of 1.0 × 10 –3 mol dm –3 juglone solution.
See it on the paper → - 9700/51 · October/November 2025 · Q1b(ii)[1]
Outline one improvement the student could make to reduce the percentage error while carrying out the dilution.
See it on the paper → - 9700/41 · May/June 2025 · Q4a[3]
Identify three similarities between the artificial photosynthesis process shown in Fig. 4.1 and the normal process of photosynthesis.
See it on the paper → - 9700/41 · May/June 2025 · Q4c(i)[1]
Name the products of the light-dependent stage of photosynthesis.
See it on the paper → - 9700/41 · May/June 2025 · Q4c(ii)[4]
Some of the protein components of the thylakoid membrane have a role in the light-dependent stage of photosynthesis. Explain the roles of the different proteins that function in the light-dependent stage of photosynthesis.
See it on the paper → - 9700/41 · May/June 2025 · Q4d[1]
The products of the light-dependent stage of photosynthesis are used in the Calvin cycle. Calvin cycle intermediates are used to produce amino acids, carbohydrates and lipids. Name the Calvin cycle intermediate that can be used to produce starch.
See it on the paper → - 9700/41 · May/June 2025 · Q4e[3]
Scientists claim that the artificial photosynthesis process shown in Fig. 4.1 is more efficient at converting light energy into food than normal photosynthesis by crop plants. Give reasons why this claim may or may not be true. true not true
See it on the paper → - 9700/42 · May/June 2025 · Q8c(i)[1]
State which photosystem is involved in the release of oxygen.
See it on the paper → - 9700/42 · May/June 2025 · Q8c(ii)[4]
With reference to Fig. 8.2: • • explain the curve between A and B explain why the curve levels off after C.
See it on the paper → - 9700/43 · May/June 2025 · Q7a(i)[2]
identify the structures involved in the production of rubisco
See it on the paper → - 9700/43 · May/June 2025 · Q7a(ii)[1]
identify the structure that contains a high concentration of protons in daylight.
See it on the paper → - 9700/43 · May/June 2025 · Q7b[3]
A student carried out paper chromatography on a solution containing a mixture of chloroplast pigments. The results are shown in Table 7.1. chlorophyll a chlorophyll b carotene distance travelled by solvent from baseline / cm R f 6.5 8.9 0.73 4.6 8.9 0.52 8.9 0. 8.2 8.9 Complete Table 7.1. pigment distance travelled by...
See it on the paper → - 9700/43 · May/June 2025 · Q7c[4]
Fig. 7.1 shows the absorption spectrum for carotene and for chlorophyll a. carotene chlorophyll a absorbance 200 300 400 500 600 700 wavelength / nm Fig. 7.1 With reference to Fig. 7.1, describe and explain the role of carotene in photosynthesis.
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What examiners said
While recognising that chlorophyll b is an accessory pigment that absorbs light, many responses did not explain the significance of this in that the wavelengths absorbed are different to those absorbed by the primary pigment. This is important for extending the range of wavelengths that can be used for photosynthesis. A common error was to state that the accessory pigments pass light on to the re...
— Examiner report, February/March 2025, 9700/42 Q9(a) (Cambridge)
Candidates were asked to describe the results of the experiment. Few described the shape of the curves accurately to reflect the fact that the rate of production of oxygen increased with light intensity at first and then levelled off. Most stated that the mutant plant had a higher rate of photosynthesis than the normal plant, but many did not support this statement by quoting data from the graph.
— Examiner report, February/March 2025, 9700/42 Q9(b)(i) (Cambridge)
Most responses noted that more light would be absorbed by the mutant plants leading to a higher rate of photosynthesis as a result of the greater production of ATP in the light-dependent reactions. Fewer considered the importance of an increased production of reduced NADP. Only stronger responses related the increase in the rate of photosynthesis to increased growth through increased production o...
— Examiner report, February/March 2025, 9700/42 Q9(b)(ii) (Cambridge)
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