48 exam-style questions on Photosynthesis — topic C1.3 of Interaction and interdependence in the IB Biology syllabus — with answers and explanations. Samples below; the full set is free with an account.
In a plant cell, photosynthesis takes place in the
Answer: chloroplast
Chloroplasts contain chlorophyll, which absorbs light energy for photosynthesis.
Which of the following is NOT normally a limiting factor for the rate of photosynthesis?
Answer: oxygen concentration
Light, CO₂ and temperature can each limit the rate; oxygen is a product and does not normally limit photosynthesis.
Determine which factor, when in short supply, would limit the rate of photosynthesis on a warm, brightly lit day.
Answer: Carbon dioxide concentration
When light and temperature are high, carbon dioxide often becomes the limiting factor because it is the raw material fixed in the Calvin cycle.
State the source of the oxygen released as a by-product of photosynthesis.
Answer: Water
The oxygen comes from the photolysis (splitting) of water in the light-dependent reactions, not from carbon dioxide.
An action spectrum of photosynthesis closely matches the absorption spectrum of chlorophyll. Explain what this correlation supports.
Answer: That the light-absorbing pigments drive photosynthesis
The close match between wavelengths absorbed and wavelengths that drive photosynthesis indicates that chlorophyll is the pigment capturing the light energy used.
Determine which products of the light-dependent reactions are required to run the Calvin cycle.
Answer: ATP and NADPH
The light-dependent reactions supply ATP and reduced NADPH, which provide energy and reducing power for carbon fixation in the Calvin cycle.
That was 6 of 48 Photosynthesis questions.
Practise all 48 freeStateAO1 · 1–2 marks
One word or one short sentence. No explanation, no working: the mark is for the fact itself.
DetermineAO3 · 3–8 marks
Obtain the only possible answer — by calculation, from the graph or by reasoning — and show how.
OutlineAO2 · 1–4 marks
A brief account or summary: the main points in two or three sentences, no evaluation.
48 Photosynthesis questions — free with an account. Spaced repetition, streaks and full exam simulations included.
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