IGCSE Biology: Plant nutrition — Practice Questions (Cambridge 0610)

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs — Cambridge International holds copyright in its own papers. Use these alongside the official past papers available from your board.

Each question practises a skill tested in the June 2024 Paper 42. After each answer there is an examiner insight, a mark-scheme insight or a tip, and (where a close match exists) the real question to try next. Questions marked (Extended) test Supplement content.

Tier note: questions marked (Extended) go beyond 0610 Core: the balanced chemical equation for photosynthesis and limiting factors (6.1, Supplement outcomes 10–11). All other questions are answerable by a 0610 Core candidate.

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Questions

1. A gardener grows lettuces in soil that is short of some mineral ions.

(a) Name the mineral ion that the lettuces need to make chlorophyll.

(b) Name the mineral ion that the lettuces need to make amino acids. [2]

2. (Extended) State the balanced chemical equation for photosynthesis. [2]

3. A student sets up three sealed tubes of hydrogencarbonate indicator, which all start orange-red. Tube A contains pondweed and is placed in bright light. Tube B contains pondweed and is wrapped in foil. Tube C contains no pondweed and is placed in bright light. After one hour, tube A is purple, tube B is yellow and tube C is still orange-red. Carbon dioxide forms an acid when it dissolves.

(a) Explain why tube A turned purple.

(b) Explain why tube B turned yellow.

(c) State the purpose of tube C. [5]

4. (Extended) A scientist measures the rate of photosynthesis of a plant at 15 °C and at normal air carbon dioxide concentration. As she increases the light intensity from zero, the rate rises steadily at first. Above a certain light intensity, the rate stays the same however bright the light becomes.

(a) State the factor limiting the rate of photosynthesis at low light intensities.

(b) Suggest two factors that could be limiting the rate when it stays the same at high light intensities. [3]

5. (Extended) In winter, a tomato grower keeps her greenhouse at 25 °C, switches on lamps in the evening and burns a fuel that releases carbon dioxide into the air inside. Explain, in terms of limiting factors, how each of these three actions increases the yield of tomatoes. [3]

6. Glucose made in photosynthesis is converted into other substances. State what glucose is converted into:

(a) for storage in a potato tuber

(b) to build cell walls

(c) for transport around the plant in the phloem. [3]

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Answers

1. (a) Magnesium (ions) [1].

(b) Nitrate (ions) [1].

Examiner insight (Cambridge 0610 June 2024 examiner report, Paper 42, Question 4(a)): Magnesium was the usual correct answer for making chlorophyll, but “nitrogen” was a common wrong answer. Learn the pairs: magnesium for chlorophyll, nitrate for amino acids.

Source for the examiner insights on this page: Cambridge IGCSE Biology 0610 June 2024 Principal Examiner Report for Teachers, Paper 0610/42 section, paraphrased.

Try the real question next: Cambridge IGCSE Biology 0610, June 2024, Paper 42, Question 4(a).

2. (Extended) 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ [1 for correct formulae, 1 for correct balancing]. Light and chlorophyll can be written above the arrow. Check: 6 C, 12 H and 18 O on each side.

Tip: The photosynthesis equation is the aerobic respiration equation written backwards. If you know one, you know the other, but check which way round the question wants.

3. (a) In the light the pondweed photosynthesises faster than it respires [1], so overall carbon dioxide is removed from the water, which becomes less acidic / more alkaline (pH rises) [1].

(b) In the dark there is no photosynthesis, but the pondweed still respires, releasing carbon dioxide [1], so the water becomes more acidic (pH falls) [1].

(c) It is a control: it shows that the colour change is caused by the pondweed, not by the light or the indicator itself [1].

Examiner insight (Cambridge 0610 June 2024 examiner report, Paper 42, Question 4(b)(i)): In a similar two-tube algae investigation, a considerable number of candidates did not mention respiration at all, wrote about oxygen instead of carbon dioxide, or got the direction of the pH change the wrong way round. Plants respire in the light and the dark; link carbon dioxide to acidity every time.

Try the real question next: Cambridge IGCSE Biology 0610, June 2024, Paper 42, Question 4(b)(i).

4. (Extended) (a) Light intensity [1].

(b) Any two of: carbon dioxide concentration [1]; temperature [1]; amount of chlorophyll / number of chloroplasts [1]. Max [2].

Examiner insight (Cambridge 0610 June 2024 examiner report, Paper 42, Question 4(b)(ii)): Many candidates named more than one limiting factor on the rising part of the curve, or said light intensity was still limiting on the flat part. Others were too vague when suggesting carbon dioxide as a limiting factor, so always write carbon dioxide concentration.

Try the real question next: Cambridge IGCSE Biology 0610, June 2024, Paper 42, Question 4(b)(ii).

5. (Extended) Heating to 25 °C means temperature is no longer limiting: the enzymes controlling photosynthesis would work slowly in cold winter air [1]. The lamps increase light intensity and give extra hours of light, so light is no longer limiting [1]. Burning the fuel raises the carbon dioxide concentration, so carbon dioxide is no longer limiting [1]. The faster rate of photosynthesis makes more carbohydrate for growth and fruit.

Tip: For each action, name the factor and say it is no longer limiting. An answer that just says “it helps photosynthesis” three times gains nothing.

6. (a) Starch [1].

(b) Cellulose [1].

(c) Sucrose [1].

Tip: Starch is for storage, cellulose is for structure, sucrose is for transport. Glucose itself is used in respiration.

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Where marks are usually lost

• Writing “nitrogen” when the answer is magnesium (for chlorophyll) or nitrate (for amino acids).
• Forgetting that plants respire all the time, in light and dark.
• Getting the direction of the pH change wrong: more carbon dioxide means more acidic.
• Naming more than one limiting factor where the rate rises with light intensity.
• Writing “carbon dioxide” when the answer needs carbon dioxide concentration.