1 markWhich statement(s) correctly describe(s) chloroplast structure?
| 1 | Thylakoids stack together to form lamellae |
| 2 | Thylakoid membranes contain photosystems 1 and 2 |
| 3 | Chloroplasts are surrounded by a double membrane |
1, 2 and 3
Only 1 and 2
Only 2 and 3
Only 1
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1 markWhich statement(s) correctly describe(s) photosynthetic pigments in photosynthesis?
| 1 | Carotenoids are accessory pigments |
| 2 | The pigments pass electrons to the electron transport chain |
| 3 | Chlorophylls absorb light in the green part of the spectrum |
1, 2 and 3
Only 1 and 2
Only 2 and 3
Only 1
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1 markBelow is a diagram of the Calvin cycle.
Which row in the table correctly identifies compounds X, Y and Z shown in the diagram?
| Compound X | Compound Y | Compound Z | |
| A | Ribulose bisphosphate (RuBP) | Triose phosphate | NADPH |
| B | Triose phosphate | Ribulose bisphosphate (RuBP) | NADPH |
| C | Ribulose bisphosphate carboxylase | Glucose | NADP |
| D | Ribulose bisphosphate (RuBP) | Hexose sugars | NADP |
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1 markThe graph below shows the effect of carbon dioxide concentration on the rate of photosynthesis.
Which of the following statements about the graph is correct?
There is a positive correlation between carbon dioxide concentration and rate of photosynthesis
At the point labelled P, photosynthesis could be limited by light intensity
At the point labelled P, photosynthesis could be limited by carbon dioxide concentration
At the point labelled P, photosynthesis reaction rate is decreasing
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1 markWhich statement(s) about the relationship between the light-dependent reaction and the light-independent reaction in photosynthesis is/are correct?
| 1 | The light-independent reaction can still continue in long periods of darkness |
| 2 | Reduced NADP is used in the light-independent reaction to produce triose phosphate |
| 3 | ATP produced in the light-dependent reaction is used to produce ribulose bisphosphate (RuBP). |
1, 2 and 3
Only 1 and 2
Only 2 and 3
Only 1
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1 markCyanobacteria are photosynthetic prokaryotes.
A scientist exposed cyanobacteria to light of different colours and intensities and made the following observations:
Which of the following statements, A to D, correctly explains these observations?
The pigments in cyanobacteria absorb blue light and light intensity is a limiting factor for the rate of photosynthesis.
The pigments in cyanobacteria absorb red light and light intensity is not a limiting factor for the rate of photosynthesis.
The pigments in cyanobacteria absorb blue light and light intensity is not a limiting factor for the rate of photosynthesis.
The pigments in cyanobacteria absorb red light and light intensity is a limiting factor for the rate of photosynthesis.
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1 markWhich of the following, A to D, is a similarity in the way ATP is made in respiration and photosynthesis?
Both involve NAD.
Both involve substrate level phosphorylation.
Both involve photons.
Both involve proton gradients.
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1 markWhich of the images, A to D, correctly summarises photosynthesis?
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1 markRuBisCO is an enzyme that fixes carbon dioxide in photosynthesis. In some conditions, RuBisCO also carries out oxygen fixation.
The graph below shows how the carbon dioxide and oxygen fixing activities of RuBisCO are affected by temperature.
What are the correct percentage changes in RuBisCO carbon dioxide and oxygen fixing activities between 30 °C and 40 °C?
Carbon dioxide fixation –12.7 %, oxygen fixation 23.3 %.
Carbon dioxide fixation –14.6 %, oxygen fixation 18.9 %.
Carbon dioxide fixation –2.4 %, oxygen fixation 54.2 %.
Carbon dioxide fixation –3.6 %, oxygen fixation 35.1 %.
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1 markPhospholipid bilayers play crucial roles within plant cells.
Which of the following statements linked to the importance of membranes in plant cells is/are true?
| Statement 1: | ATP synthase embedded in thylakoid membranes maintains chemiosmotic gradients. |
| Statement 2: | Phospholipid bilayers within the chloroplast are impermeable to protons. |
| Statement 3: | Thylakoid membranes contain electron transport chain proteins. |
1, 2 and 3
Only 1 and 2
Only 2 and 3
Only 1
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1 markDuring photosynthesis the following reaction occurs.
2H2O → 4e- + 4H+ + O2
Which of the following statements relating to this reaction is not correct?
All of the oxygen derived from the splitting of water is used for cellular respiration.
Water is broken down using energy derived from light.
The splitting of water replaces electrons lost during photoexcitation of photosystem II.
Electrons derived from the splitting of water are used in subsequent stages of photosynthesis.
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1 markThe graph below shows how light intensity affects the rate of carbon dioxide absorption by leaves at different temperatures and carbon dioxide concentrations.
Which of the following rows correctly identifies the possible limiting factor for photosynthesis at I, II, III and IV?
| I | II | III | IV | |
| A. | CO2 concentration | Light intensity | Temperature | Photosynthetic capacity |
| B. | Light intensity | Temperature | CO2 concentration | Photosynthetic capacity |
| C. | Temperature | Light intensity | Photosynthetic capacity | CO2 concentration |
| D. | Light intensity | CO2 concentration | Temperature | Photosynthetic capacity |
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1 markPaper chromatography can be used to separate photosynthetic pigments obtained from chloroplasts. The chromatography strip shows distinct coloured pigment bands.
The table show the Rf values of the separated pigments.
| Pigment | Rf value |
| Carotene | 0.95 |
| Chlorophyll A | 0.45 |
| Chlorophyll B | 0.35 |
| Xanthophyll | 0.51 |
Which pigment bands are represented by bands 3 and 4?
Carotene and xanthophyll
Carotene and chlorophyll A
Xanthophyll and chlorophyll A
Chlorophyll A and chlorophyll B
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The effect of different colours of light on the growth of Arabidopsis thaliana (thale cress) seedlings was studied.
Three different colours of light were tested and measurements of seedling height, shoot length, and biomass were taken.
| Colour of light | Wavelength of light (nm) |
Height of seedlings (cm) |
Shoot length (cm) |
Total biomass |
| Blue | 450 | 3.5 | 2.8 | 2.4 |
| Orange | 600 | 2.3 | 2.0 | 2.8 |
| Red | 630 | 7.4 | 6.1 | 3.7 |
What conclusions can be drawn from the data?
White light gives the optimal conditions for photosynthesis.
There is a linear relationship between wavelength of light and plant growth.
Red light enhances plant growth.
There is no correlation between total biomass and plant height.
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Which row correctly identifies products of the light dependent stage with their corresponding destination?
| Products | Destination | |
| A. | NADH, ATP | The electron transport chain |
| B. | O2, NADPH, ATP | The Calvin cycle |
| C. | Acetyl CoA, NAD, FAD | The Krebs cycle |
| D. | NADPH, ATP | The Calvin cycle |
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1 markThe image shows an electron transport chain.
Which of the following correctly describes what is happening at X and Y?
| X | Y | |
| A. | Oxidation of NADH | Oxygen acts as the terminal electron acceptor |
| B. | Photolysis of water | Reduction of NADP |
| C. | Oxidation of water | Reduction of NAD |
| D. | Photolysis of water | Oxidation of NADP |
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1 markThe diagram below shows the structure of a chloroplast.
Which of the following statements, A to D, describes an event that occurs inside the structure labelled X?
Movement of H+, against a concentration gradient, via ATP synthase
Cyclic photophosphorylation involving photosystem II
Splitting of water molecules
X contains photosystem I and photosystem II
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1 markDuring autumn the nights lengthen and temperatures fall. Observations relating to plant activity at this time of year include:
Which of the following statement(s) correctly explain(s) these observations?
| 1 | There is less synthesis of chlorophyll a |
| 2 | There is reduced carbon fixation by rubisco |
| 3 | Xanthophylls and carotenoids absorb light at wavelengths of 600-650 nm |
1, 2 and 3
Only 1 and 2
Only 2 and 3
Only 1
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1 markA student investigated the rate of the light-dependent stage of photosynthesis at different light intensities.
DCPIP indicator was added into a series of test tubes containing leaf extract, and each tube was exposed to a different light intensity.
The time taken for the solution to turn green is recorded.
Which of the following statement(s) about DCPIP is/are correct?
| 1 | DCPIP undergoes reduction during the light dependent reactions |
| 2 | The faster the DCPIP turns from blue to colourless, the more glucose is produced |
| 3 | The DCPIP indicator turns green when the light dependent reactions are taking place |
1, 2 and 3
Only 1 and 2
Only 2 and 3
Only 1
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1 markThe table below shows how concentrations of GP and RuBP are affected by different carbon dioxide concentrations.
| Relative percentage concentration of carbon dioxide, CO2 (%) |
Concentration of glycerate 3-phosphate, GP (µmol) |
Concentration of ribulose bisphosphate, RuBP (µmol) |
| 0.01 | 1.2 | 1.5 |
| 0.02 | 1.3 | 1.5 |
| 0.03 | 1.4 | 1.3 |
| 0.04 | 1.5 | 1.2 |
Which of the following statements could explain the data provided?
| 1 | There is a reduction in ATP and reduced NADP from the light dependent stage |
| 2 | Rubisco is inhibited by oxygen |
| 3 | Triose phosphate is used to make glucose |
1, 2 and 3
Only 1 and 2
Only 2 and 3
Only 1
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1 markWhich of the following statements about triose phosphate is correct?
Triose phosphate production is unaffected by the absence of light
Glycerate 3-phosphate is reduced and loses a phosphate group to form triose phosphate
Triose phosphate is used to produce starch
Six turns of the Calvin cycle are needed to regenerate 6 RuBP from 12 triose phosphate
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