Photosynthesis — AS & A Level Biology (9700) questions by topic
17 real questions make up this set, drawn from 2023 to 2025 papers, and marks run unusually high for their number, from 6 to 21, so most answers require several connected points rather than a single fact. Chloroplast structure and the light-dependent and light-independent stages recur throughout: naming the thylakoid membrane structures shown in a chloroplast diagram, describing non-cyclic photophosphorylation, and explaining why plants open and close stomata in a daily rhythm, with describe, identify and explain the leading command words.
Practising full-stage descriptions with instant marking is valuable here, since confusing the thylakoid membrane with the thylakoid lumen, or naming the wrong metabolic cycle, is caught immediately.
What examiners look for
- A frequent error names granum or granules where thylakoid is the correct structural term.
- Answers sometimes state only that 'thylakoids contain pigments' without any reference to the membrane itself.
- The Calvin cycle is sometimes confused with the Krebs cycle or the carbon dioxide fixation cycle by name.
- ATP is occasionally, and incorrectly, identified as a product that leaves the chloroplast from the light-dependent reaction.
- Strong answers correctly identify the thylakoid membrane as the site of photophosphorylation and ATP synthesis, name the Calvin cycle in the stroma, and explain RuBP regeneration using five sixths of the available triose phosphate.
May–June 2025, Paper 41
Scientists have developed a new process called artificial photosynthesis. Fig. 4.1 shows the process of artificial photosynthesis. In this process, solar panels capture light…
Answer this question and get it marked →May–June 2025, Paper 43
A chloroplast is composed of many structures, each with a different function. Several chloroplast structures are listed: stroma, lamellae, thylakoid membrane, ribosome, thylakoid…
Answer this question and get it marked →May–June 2025, Paper 44
Photosynthesis involves both the light-dependent stage and the light-independent stage. Describe non-cyclic photophosphorylation.
Answer this question and get it marked →May–June 2024, Paper 41
Photosynthesis is the energy transfer process that occurs in chloroplasts. Fig. 5.1 shows some biochemical events that occur in a chloroplast during the light-dependent stage of…
Answer this question and get it marked →May–June 2024, Paper 42
A student investigated the effect of temperature on the rate of photosynthesis at two different light intensities. The rate of photosynthesis was determined by measuring the rate…
Answer this question and get it marked →October–November 2024, Paper 42
Paper chromatography is a technique that can be used to separate and identify different chloroplast pigments. Describe how the results of paper chromatography can be used to…
Answer this question and get it marked →October–November 2024, Paper 43
The leaves of many plants have stomata that show a regular daily rhythm of opening and closing over a period of 24 hours. Explain why it is important for plants to open and close…
Answer this question and get it marked →October–November 2024, Paper 53
A student prepared extracts of the photosynthetic pigments from R. salina and S. costatum. The student carried out chromatography to identify and compare the pigments in the two…
Answer this question and get it marked →February–March 2023, Paper 42
Describe the functions of the internal membranes of the chloroplast in photosynthesis.
Answer this question and get it marked →May–June 2023, Paper 41
Fig. 1.1 shows a transmission electron micrograph of part of a chloroplast (magnification x80 000), with four structures labelled A, B, C and D. A is the stroma, B is the…
Answer this question and get it marked →May–June 2023, Paper 42
In plants such as rice, Oryza sativa, rubisco has a low rate of activity, which in turn affects the rate of photosynthesis. The cereal crop sorghum, Sorghum bicolor, has a high…
Answer this question and get it marked →May–June 2023, Paper 43
Fig. 8.1 is a diagram of a chloroplast, with four structures labelled K, L, M and N (K is the outer envelope membrane region, L is a thylakoid membrane, M is the thylakoid space,…
Answer this question and get it marked →October–November 2023, Paper 41
Chloroplasts carry out photosynthesis. Fig. 1.1 shows some structural features of a chloroplast and some processes that occur within it: CO₂ entering and product D leaving from…
Answer this question and get it marked →Environmental conditions such as light intensity affect plant physiology. Use the letter X to identify a point on the sketch graph in Fig. 8.1 where light intensity is acting as a…
Answer this question and get it marked →October–November 2023, Paper 42
Non-cyclic photophosphorylation occurs in the light-dependent stage of photosynthesis. Outline the main features of non-cyclic photophosphorylation.
Answer this question and get it marked →October–November 2023, Paper 43
Chloroplasts carry out photosynthesis. Fig. 1.1 shows some structural features of a chloroplast and some processes that occur within it. Identify the structures labelled A in Fig.…
Answer this question and get it marked →Environmental conditions such as light intensity affect plant physiology. Use the letter X to identify a point on the sketch graph in Fig. 8.1 where light intensity is acting as a…
Answer this question and get it marked →Other AS & A Level Biology topics
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