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CAIE A Level Biology 9700

Photosynthesis questions

Exam-style questions on Photosynthesis, ordered from foundation to challenge. Pick one, write your answer the way you would in the exam, and it comes back marked against the mark scheme, point by point.

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Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.

  1. Describe5 marksStandardA student investigated the effect of light intensity on the rate of photosynthesis of the aquatic plant Elodea canadensis. The rate was measured by counting the number of oxygen bubbles released per minute at different…
  2. Describe4 marksStandardAn electron micrograph of a chloroplast from a tomato leaf shows numerous flattened sacs (thylakoids) stacked into grana, surrounded by a semi-fluid stroma. Describe how the structural features of the grana and the…
  3. Predict4 marksStandardA student investigated the effect of light intensity on the rate of photosynthesis using a suspension of chloroplasts and DCPIP. The table shows the time taken for the DCPIP to become colourless at different light…
  4. Predict4 marksStandardA student investigated the effect of light intensity on the rate of photosynthesis using a suspension of isolated chloroplasts and the redox indicator DCPIP. DCPIP is blue when oxidised and becomes colourless when…
  5. Predict5 marksStandardAn experiment was set up to investigate the effect of light intensity, carbon dioxide concentration, and temperature on the rate of photosynthesis in the aquatic plant Elodea. The rate was measured by counting the…
  6. Describe4 marksStandardA student investigated the effect of light intensity on the rate of photosynthesis in the aquatic plant Elodea. The plant was placed in a beaker of water at 20 °C with a constant concentration of dissolved carbon…
  7. Explain4 marksStandardIn an experiment, a plant cell is supplied with carbon dioxide containing the radioactive isotope ^14C. A radioactive carbon atom is incorporated into a molecule of triose phosphate (TP) in the Calvin cycle. Explain…
  8. Outline4 marksStandardA researcher is investigating the light-dependent reactions of photosynthesis in isolated chloroplasts. As part of the investigation, the researcher compares cyclic and non-cyclic photophosphorylation. Outline four…
  9. Explain4 marksStandardA student investigated the effect of light intensity on the rate of photosynthesis of an aquatic plant (Elodea) at two different temperatures. The oxygen evolution (mm³ min⁻¹) was measured. The results are shown in the…
  10. Explain4 marksStandardThe Calvin cycle of photosynthesis produces several three-carbon intermediates. One of these intermediates is used to make carbohydrates such as starch and sucrose, while another is used to make amino acids such as…
  11. Explain4 marksStandardA student investigated the effect of light intensity on the rate of photosynthesis in the aquatic plant Elodea canadensis at two different temperatures, 15°C and 25°C. The rate of photosynthesis was measured by…
  12. Describe4 marksStandardA student investigated the effect of light intensity on the rate of photosynthesis in an aquatic plant (Elodea). The plant was placed in a beaker of water at 20°C with excess carbon dioxide (by adding sodium…
  13. Describe5 marksStandardA student placed a pondweed in a beaker of water and measured the number of oxygen bubbles produced per minute at different distances from a lamp. The results are shown in the table. Distance from lamp / cm Bubbles per…
  14. Describe5 marksStandardA student examines a transmission electron micrograph of a chloroplast isolated from a spinach leaf. Describe the main structural features of the chloroplast visible in the micrograph and explain how each feature is…
  15. Outline4 marksStandardA plant leaf is supplied with 14CO₂ in the light. After a short time, radioactive carbon is detected in triose phosphate (TP). Outline the sequence of events that leads to a carbon atom from carbon dioxide becoming…
  16. Outline4 marksStandardThe table below shows the percentage of incident light absorbed by chlorophyll a and chlorophyll b at selected wavelengths. Wavelength / nm Chlorophyll a absorption / % Chlorophyll b absorption / % 400 40 35 450 60 50…
  17. Predict4 marksStandardAn experiment was carried out to investigate the effect of light intensity on the light-dependent stage of photosynthesis. A suspension of isolated chloroplasts was mixed with DCPIP, a blue redox indicator that becomes…
  18. Describe5 marksStandardDescribe the differences between cyclic and non-cyclic photophosphorylation in the light-dependent stage of photosynthesis. Include in your answer the photosystems used, the products formed, and the role of water.
  19. Outline5 marksStandardA student used paper chromatography to separate the photosynthetic pigments from a leaf extract. The solvent front moved 15.0 cm from the origin. The distances moved by the four main pigments were: Carotene: 14.5 cm…
  20. Describe5 marksStandardDescribe how protons (H+) move across the thylakoid membrane during the light-dependent stage of photosynthesis and explain how this movement is linked to the synthesis of ATP. Include the role of photolysis of water.
  21. Explain5 marksStandardWith reference to the structural features of a chloroplast, explain how it is adapted to carry out the light-dependent and light-independent stages of photosynthesis.
  22. Describe4 marksStandardThe table below shows the percentage of incident light absorbed by chlorophyll a and chlorophyll b at different wavelengths of visible light. Wavelength (nm) % Absorption by Chlorophyll a % Absorption by Chlorophyll b…
  23. Explain5 marksStandardA student investigated the effect of carbon dioxide concentration on the rate of photosynthesis in the aquatic plant Elodea. The plant was placed in water at 20 °C and exposed to a constant light intensity. Different…
  24. Predict5 marksStandardA student investigated the effect of light intensity and carbon dioxide concentration on the rate of photosynthesis in the aquatic plant Elodea. The rate was measured as the number of oxygen bubbles produced per…
  25. Outline5 marksStandardA student investigated the absorption of light by chlorophyll a and chlorophyll b. The table shows the percentage absorption at different wavelengths. Wavelength (nm) Chlorophyll a absorption (%) Chlorophyll b…
  26. Explain5 marksStandardA scientist adds a radioactive carbon atom in a molecule of CO₂ to a suspension of illuminated isolated chloroplasts. Describe the pathway of this carbon atom as it is incorporated into a molecule of triose phosphate…
  27. Predict5 marksStandardA student investigates the effect of light intensity and carbon dioxide concentration on the rate of photosynthesis in the aquatic plant Elodea. They place cuttings of Elodea in beakers of water at 20 °C and count the…
  28. Explain5 marksStandardA student investigated the effect of carbon dioxide concentration on the rate of photosynthesis in the aquatic plant Elodea canadensis. Shoots were placed in test tubes containing different concentrations of sodium…
  29. Outline5 marksStandardA student investigated the Calvin cycle using isolated chloroplasts illuminated with light. They supplied the chloroplasts with radioactive 14CO2 and measured the appearance of radioactivity in various compounds over…
  30. Describe5 marksStandardA student investigated the effect of light intensity on the rate of photosynthesis in the aquatic plant Elodea. The student placed a piece of Elodea in a beaker of water and counted the number of bubbles of oxygen…
  31. Explain5 marksStandardThe table shows the rate of photosynthesis (in arbitrary units) measured at different carbon dioxide concentrations under two light intensities: low (200 μmol m−2 s−1) and high (800 μmol m−2 s−1). CO2 concentration /…
  32. Explain4 marksStandardA researcher treats isolated chloroplasts with an inhibitor that prevents the flow of electrons through the electron transport chain in the thylakoid membrane. They then measure the pH of the thylakoid lumen and the…
  33. Describe5 marksChallengeA student investigated the effect of light intensity on the rate of photosynthesis in an aquatic plant (Elodea canadensis). The rate was measured by counting the number of oxygen bubbles released per minute at…
  34. Explain6 marksChallengeA student investigated the effect of carbon dioxide concentration on the rate of photosynthesis in the aquatic plant Elodea at two different light intensities. The temperature was kept constant at 20°C. The rate was…
  35. Describe5 marksChallengeChloroplasts have thylakoid membranes arranged in stacks called grana, connected by intergranal lamellae. The stroma is the aqueous fluid that surrounds the grana. Describe how this structure is adapted for the…
  36. Explain6 marksChallengeA student investigated the effect of light intensity on the rate of photosynthesis in an aquatic plant, Elodea canadensis, at two different temperatures. The rate was measured as the volume of oxygen produced per hour…
  37. Outline7 marksChallengeThe table below shows the percentage absorption of light at different wavelengths for chlorophyll a and chlorophyll b extracted from a plant. Wavelength (nm) Chlorophyll a absorption (%) Chlorophyll b absorption (%)…
  38. Describe5 marksChallengeIn an investigation, students placed a sprig of Elodea in a beaker of water containing 0.05% sodium hydrogen carbonate solution. They measured the rate of photosynthesis by counting the number of oxygen bubbles…
  39. Describe5 marksChallengeA researcher investigates the fate of carbon fixed during photosynthesis in a plant. She supplies the plant with carbon dioxide labelled with radioactive carbon-14 for a short period, then transfers the plant to…
  40. Outline7 marksChallengeIn an experiment, isolated chloroplasts are exposed to light and supplied with ADP and NADP+. A specific inhibitor is added that prevents the movement of protons from the thylakoid space into the stroma through ATP…
  41. Describe5 marksChallengeA student investigated the effect of light intensity on the rate of photosynthesis in the aquatic plant Elodea. The plant was placed in a beaker of water at a constant temperature of 20°C. The light intensity was…
  42. Predict7 marksChallengeAn investigation measured the rate of photosynthesis in a plant leaf at different light intensities and carbon dioxide concentrations. The temperature was kept constant at 20°C. The results are shown in the table…
  43. Predict7 marksChallengeA student investigated the effect of light intensity on the rate of the light-dependent stage of photosynthesis using a suspension of isolated chloroplasts and the redox indicator DCPIP (2,6-dichlorophenolindophenol)…
  44. Explain6 marksChallengeThe table shows the percentage absorption of light at different wavelengths by chlorophyll a and chlorophyll b extracted from a plant. Wavelength (nm) Chlorophyll a (% absorption) Chlorophyll b (% absorption) 430 80 55…
  45. Predict7 marksChallengeA student investigates the rate of photosynthesis in the aquatic plant Elodea canadensis by measuring the volume of oxygen produced per minute. The plant is placed in a beaker of water containing different…
  46. Outline7 marksChallengeAn electron micrograph of a chloroplast from a leaf mesophyll cell shows stacked thylakoid membranes (grana) surrounded by a fluid-filled stroma. Outline how the structure of the chloroplast is adapted for the…
  47. Explain6 marksChallengeA student investigated the effect of carbon dioxide concentration on the rate of photosynthesis in the aquatic plant Elodea. The rate was measured as oxygen production (arbitrary units per minute) in a 20-minute…
  48. Explain6 marksChallengeIn photosynthesis, the Calvin cycle uses ATP and reduced NADP from the light-dependent stage to fix carbon dioxide. The triose phosphate (TP) produced can be used to synthesise various organic compounds. Explain how…
  49. Explain6 marksChallengeA plant is placed under a light source that emits only far-red light of wavelength 720 nm. It is known that this wavelength is absorbed by photosystem I (PSI) but not by photosystem II (PSII). Explain the effect of…
  50. Describe5 marksChallengeDescribe the sequence of events in the Calvin cycle that converts carbon dioxide into triose phosphate (TP), including the roles of the products of the light-dependent stage. Start your answer with the fixation of…
  51. Describe5 marksChallengeAn experiment was carried out to investigate the effect of light intensity on the rate of photosynthesis in an aquatic plant (Elodea). The number of oxygen bubbles produced per minute was recorded at different light…
  52. Describe5 marksChallengeA student extracted pigments from a leaf and separated them by paper chromatography using a non-polar solvent. The following Rf values were calculated: Carotene: 0.95 Xanthophyll: 0.71 Chlorophyll a: 0.65 Chlorophyll…
  53. Describe5 marksChallengeDescribe how the movement of protons across the thylakoid membrane during the light-dependent stage of photosynthesis leads to the synthesis of ATP.
  54. Outline7 marksChallengeTable 1 shows features of cyclic and non-cyclic photophosphorylation. Some entries are missing. Outline the missing information by writing the correct term(s) for (a) to (g). Feature Cyclic photophosphorylation…
  55. Explain6 marksChallengeA student investigated the effect of light intensity and temperature on the rate of photosynthesis in Elodea canadensis. The rate was measured by counting oxygen bubbles produced per minute. The results are shown in…
  56. Predict7 marksChallengeA student prepared a suspension of isolated chloroplasts and added DCPIP. The suspension was divided into test tubes and placed at different distances from a lamp to vary light intensity. The time taken for the blue…
  57. Explain6 marksChallengeA student extracted pigments from a variegated leaf and separated them using paper chromatography with a solvent that travelled 12.0 cm from the origin. The distances travelled by each pigment are shown in the table…
  58. Explain6 marksChallengeA scientist incubated isolated chloroplasts with 14C-labeled carbon dioxide (14CO2) in the light. After a brief exposure, the first organic compound containing 14C was identified as 3-phosphoglycerate (GP). After a…
  59. Describe5 marksChallengeA student investigated the effect of light intensity on the rate of photosynthesis in an aquatic plant (Elodea canadensis). The plant was placed in a beaker of water at a constant temperature of 20°C. The number of…