Photosynthesis

The diagram depicts a plant cell. In comparison with the rest of the cell, which row states the concentrations of oxygen and magnesium inside structure P during the daytime?

May/June 2015

Certain kinds of bacteria produce carbohydrates from carbon dioxide and water by using energy from sunlight. Which of the following best describes these bacteria?

May/June 2015

The diagram shows a plant cell. In comparison with the other parts of the cell, which row describes the concentrations of oxygen and magnesium inside structure P during the daytime?

May/June 2015

A plant has leaves that are green in the middle but white at the margins. The plant is destarched and then one of its leaves is partly covered on both sides with black paper, as shown. It is then left in bright light for 48 hours. After that, the leaf is tested for starch. Which diagram shows the colours obtained?

May/June 2015

On a sunny day, which material does a leaf excrete?

May/June 2016

Which kind of organism relies directly on light energy for its nutrition?

May/June 2016

Which row indicates what occurs in photosynthesis?

May/June 2016

The graph illustrates how a plant’s rate of photosynthesis changes as light intensity changes at two different carbon dioxide concentrations. The temperature is maintained at $20^\circ\text{C}$. Which factor is limiting the rate of photosynthesis at point X?

May/June 2016

Which process in a developing seedling requires light energy?

May/June 2016

A leaf was taken from a plant that had been exposed to sunlight for eight hours. What would this leaf look like after testing with iodine solution?

May/June 2016

The graph illustrates how the rate of photosynthesis of a plant changes with light intensity at two different carbon dioxide concentrations. The temperature is maintained at $20^\f$. Which factor is limiting the rate of photosynthesis at point X?

May/June 2016

Fig. 4.1 compares the leaves of the same plant in daylight with those in darkness.

May/June 2016

The diagram illustrates cells taken from a plant leaf. Which structure is rich in magnesium?

May/June 2017

The diagram shows several substances present in plant cells. Which part of the diagram shows the end products of photosynthesis?

May/June 2017

Test-tubes P and Q were each filled with a solution of red hydrogencarbonate indicator. Hydrogencarbonate indicator turns yellow when the carbon dioxide concentration increases and turns purple when the carbon dioxide concentration decreases. Equal pieces of the same aquatic plant were placed in tubes P and Q. Tube P was left uncovered, while tube Q was covered with a black light-proof cover. The tubes were kept for four hours in a warm room in sunlight. What would be the colour of the hydrogencarbonate indicator in the two tubes after four hours?

May/June 2017

Which graph illustrates the effect of temperature on the rate of photosynthesis?

May/June 2017

The diagram shows several substances present in plant cells. Which part of the diagram indicates the final products of photosynthesis?

May/June 2017

Two test-tubes, P and Q, were prepared, and each one contained a solution of red hydrogencarbonate indicator. Hydrogencarbonate indicator becomes yellow when the carbon dioxide concentration rises and turns purple when the carbon dioxide concentration falls. Matching pieces of the same aquatic plant were put into tubes P and Q. Tube P was left uncovered, whereas tube Q was covered with a black light-proof cover. The tubes were then kept in a warm room in sunlight for four hours. What colour would the hydrogencarbonate indicator be in the two tubes after four hours?

May/June 2017

Which graph illustrates how temperature affects the rate of photosynthesis?

May/June 2017

The diagram illustrates a palisade cell. Which structure is the location of photosynthesis?

May/June 2018

The diagrams illustrate an experiment used to determine the rate of photosynthesis in an aquatic plant under different conditions. Which plant gives the greatest number of bubbles per minute?

May/June 2018

The diagrams illustrate an experiment used to determine the rate of photosynthesis in an aquatic plant under different conditions. Which plant is producing the highest number of bubbles each minute?

May/June 2018

The graphs illustrate how two different conditions influence the rate of photosynthesis. Which conditions are changed in graphs 1 and 2?

May/June 2019

A plant has leaves that contain both green regions and white regions. On one leaf, part of the surface is covered with aluminium foil so that light cannot reach it. The plant is then kept beneath a lamp for 24 hours. After this period, discs are removed from the leaf areas shown and examined using iodine solution. Which leaf discs will turn blue-black when iodine solution is added?

May/June 2019

Which word equation represents photosynthesis?

May/June 2019

A student carried out an experiment to find out whether chlorophyll is necessary for photosynthesis. Which plant would be suitable for this experiment?

May/June 2019

An experiment was conducted to study how light intensity and carbon dioxide concentration affect the rate of photosynthesis. Which graph illustrates the findings of this experiment?

May/June 2021

Hydrogencarbonate indicator alters colour depending on the amount of carbon dioxide present. The table indicates the way hydrogencarbonate indicator changes colour. Four test-tubes were arranged under different conditions. The colour of hydrogencarbonate indicator in each test-tube at the beginning of the experiment and after 1 hour is also shown. Which test-tube indicates that the rates of photosynthesis and respiration are equal?

May/June 2021

Rice, maize and wheat plants provide the principal carbohydrate supply for over 60% of the human population.

May/June 2021

A plant has leaves with both green and white regions. One leaf is partly covered by aluminium foil, so that light cannot reach that part. The plant is then kept under a lamp for 24 hours. After this period, discs are removed from the labelled parts of the leaf shown and tested using iodine solution. Which leaf discs will turn blue-black when iodine solution is added?

May/June 2022

A plant has leaves that contain both green and white regions. Part of one leaf is covered with aluminium foil so that light cannot reach it. The plant is then kept under a lamp for 24 hours. After this period, discs are taken from the parts of the leaf indicated and then tested using iodine solution. Which leaf discs will turn blue-black when iodine solution is added?

May/June 2022

The graph illustrates how a plant’s rate of photosynthesis changes with light intensity. Which of the statements are correct?

May/June 2023

Fig. 6.1 illustrates the pattern of results from an investigation into how increasing light intensity affects the rate of photosynthesis.

May/June 2023

The graphs illustrate factors that affect the rate of photosynthesis. At which points on the graphs might light intensity be limiting the rate of photosynthesis?

May/June 2024

An indicator solution gives these colour changes: atmospheric carbon dioxide concentration: orange high carbon dioxide concentration: yellow low carbon dioxide concentration: purple. In the setup shown, both tubes contained orange indicator at the start of the experiment. What colours would the indicators be after three hours?

May/June 2024

What balanced chemical equation represents photosynthesis?

May/June 2025

Glucose formed during photosynthesis may be changed into other carbohydrates, or it may be used straight away as glucose. What is one immediate use of glucose in plants?

May/June 2025

Students carried out an investigation into the rate of photosynthesis at different light intensities. They measured how many oxygen bubbles a submerged aquatic plant gave off per minute when it was positioned at various distances from a light source. Which results would be expected from this investigation?

May/June 2025

Carbon dioxide pollution in the air is helping to drive global warming.

May/June 2025

Fig. 2.1 illustrates a section of the shoot from a pea seedling.

May/June 2025

Fig. 3.1 illustrates mustard plant seedlings placed in Petri dishes on moist filter paper.

May/June 2025

The diagrams illustrate a plant placed in a flask containing water. It is kept in light at $16\,^{\circ}\text{C}$ for six hours. What accounts for the change in mass after six hours?

Oct/Nov 2015

The diagrams display a plant in a flask containing water. It is kept in the light at $16\,^{\circ}\text{C}$ for six hours. What explains the mass change after six hours?

Oct/Nov 2015

A variegated plant is destarched and then exposed to sunlight for several hours. A leaf is then removed and tested with iodine solution for starch. Which diagram shows the correct results?

Oct/Nov 2015

The diagram depicts a green shoot photosynthesising beneath a glass jar. This served as the control experiment in a laboratory investigation. Which diagram shows the experiment carried out to investigate the need for carbon dioxide in photosynthesis?

Oct/Nov 2016

The diagram depicts a green shoot photosynthesising beneath a glass jar. This acted as the control experiment in a laboratory investigation. Which diagram shows the experiment set up to investigate the need for carbon dioxide in photosynthesis?

Oct/Nov 2016

Fig. 2.1 depicts part of the flowering head of a small tree that grows in tropical rainforests.

Oct/Nov 2016

The diagram illustrates the carbon cycle. At which stage in the cycle is oxygen given out by living organisms?

Oct/Nov 2017

A student carries out an investigation into how the colour of light affects the rate of photosynthesis. In three separate trials, red, blue, or green light is directed at an aquatic plant. The number of oxygen bubbles given off by the plant is counted. Each trial is repeated three times, and the mean number of bubbles is worked out. Red: $48\,\text{bubbles min}^{-1}$ Blue: $37\,\text{bubbles min}^{-1}$ Green: $12\,\text{bubbles min}^{-1}$ What accounts for these results?

Oct/Nov 2017

Part B

Oct/Nov 2017

Which graph illustrates how temperature affects the rate at which an aquatic plant releases oxygen when it is kept in strong light?

Oct/Nov 2018

The diagram shows a transverse section of part of a leaf. In light conditions, and also in darkness, how does the oxygen content of the air at X compare with that of normal atmospheric air?

Oct/Nov 2018

The experiment is arranged as shown. After 30 minutes, the volume of gas collected is measured. The experiment is carried out several more times. On each occasion, the light intensity is increased. Which graph shows the results?

Oct/Nov 2018

The diagram shows a cross-section of part of a leaf. How does the oxygen content of the air at X compare with normal atmospheric air when the leaf is in the light and when it is in the dark?

Oct/Nov 2018

Describe and explain the way in which each of the following influences the rate of photosynthesis: light intensity; temperature.

Oct/Nov 2018

The graph illustrates how the concentration of dissolved carbon dioxide in pond water changes over 24 hours.

Oct/Nov 2018

Four students are investigating a pond ecosystem on a clear sunny day. They notice that the underwater plants are releasing bubbles. What accounts for this observation?

Oct/Nov 2019

Which diagram shows substances entering and leaving a leaf while glucose is being made?

Oct/Nov 2019

A small mountain lake contains aquatic plants growing below the water on the lake bed. Soon after heavy rainfall, the mud on the lake bed is stirred up and the water level rises. Why does this make the rate of photosynthesis in these plants decrease?

Oct/Nov 2019

Some chemical symbols are shown. What equation represents photosynthesis?

Oct/Nov 2019

Which row gives the correct number of molecules, for each substance consumed and formed, during photosynthesis?

Oct/Nov 2020

The graph illustrates how the rate of photosynthesis changes as light intensity changes at two different temperatures. All other variables remain unchanged. In which parts of the graph does light intensity limit the rate of photosynthesis?

Oct/Nov 2020

The graph illustrates how the rate of photosynthesis changes with light intensity at two different temperatures. All other variables are kept constant. At which parts of the graph is light intensity the factor limiting the rate of photosynthesis?

Oct/Nov 2020

Corals consist of many tiny animals that live together in the sea, and their skeletons build coral reefs. Inside the cells of these animals are microscopic green, plant-like organisms known as algae.

Oct/Nov 2020

The graphs illustrate factors that influence the rate of photosynthesis. At which positions on the graphs might the rate of photosynthesis be restricted by light intensity?

Oct/Nov 2021

The graph illustrates how the dry mass of a seed changes as it germinates and develops. What causes the change shown between points S and T?

Oct/Nov 2021

The graphs illustrate factors that influence the rate of photosynthesis. At which points on the graphs might the rate of photosynthesis be restricted by carbon dioxide concentration?

Oct/Nov 2021

A farmer is cultivating a tomato crop.

Oct/Nov 2021

The diagram illustrates cells taken from a plant leaf. Which structure has a high concentration of magnesium?

Oct/Nov 2022

The apparatus is arranged as shown. Test-tubes $1$ and $2$ each contain limewater. Limewater is a clear solution that becomes cloudy when carbon dioxide is present. Air is pumped through the apparatus. What will the limewater look like in test-tubes $1$ and $2$ after $10$ minutes?

Oct/Nov 2022

A small mountain lake contains aquatic plants growing beneath the water on the lake bed. Soon after heavy rainfall, the mud on the lake bed is disturbed and the water level increases. Why does this lead to a decrease in the rate of photosynthesis in these plants?

Oct/Nov 2022

A small mountain lake contains aquatic plants growing below the water on the lake bed. Soon after heavy rainfall, the sediment on the lake bed is disturbed and the water level increases. Why does this make the photosynthesis rate of these plants decrease?

Oct/Nov 2022

Grapes are fruits that develop on a plant known as a grape vine. A farmer cultivates a type of grape vine called the sultana. The grapes that are produced are sold either for eating fresh or for making dried fruit known as sultanas.

Oct/Nov 2022

The diagram illustrates the movement of substances involved in photosynthesis in a leaf. Which row gives the correct labels for the diagram?

Oct/Nov 2023

The diagram shows a plant cell. Compared with the rest of the cell, which row gives the concentrations of oxygen and magnesium within structure P during daytime?

Oct/Nov 2023

The fossil fuels used as energy sources today were formed from the remains of plants and animals that became buried millions of years ago. What was the original source of the energy stored in these fossil fuels?

Oct/Nov 2023

The graph compares the rate of photosynthesis in a plant in full sunlight at two different temperatures and with different carbon dioxide concentrations. At normal atmospheric concentrations of carbon dioxide, what factor limits the rate of photosynthesis?

Oct/Nov 2024

The graphs illustrate factors that affect the rate of photosynthesis. At which points on the graphs might the rate of photosynthesis be limited by the concentration of carbon dioxide?

Oct/Nov 2024

Photosynthesis in green plants may be represented by the equation: carbon dioxide + water $\xrightarrow{\text{light and chlorophyll}}$ carbohydrate + oxygen A student used the apparatus shown in Fig. 2.1 to examine the rate of photosynthesis in an aquatic plant. After the student turned the lamp on, bubbles of oxygen were produced and drawn into the syringe. The student noted the volume of oxygen made in ten minutes. The syringe was then topped up with sodium hydrogencarbonate solution and the oxygen was collected for a further ten minutes. The student then chose to test how different colours of light affected the rate of photosynthesis. With the same plant left in the glass jar, a red transparent filter was wrapped around the glass jar so that the plant received only red light. The volume of oxygen made in ten minutes was measured. This measurement was then carried out again. Next, the red transparent filter was swapped for a green transparent filter and then for a blue transparent filter. For each filter, the volume of oxygen made in ten minutes was also measured twice. The measurements are shown in Table 2.1.

Oct/Nov 2024

Hydrogencarbonate indicator alters its colour depending on the concentration of carbon dioxide present. The table displays these colour changes. Four test-tubes were prepared under different conditions. The colour of the hydrogencarbonate indicator in each test-tube at the beginning of the experiment and after one hour is also shown. Which test-tube shows that the rates of photosynthesis and respiration are equal?

Oct/Nov 2025

Which diagram accurately connects the carbohydrates produced by photosynthesis with the ways in which they are used?

Oct/Nov 2025

An investigation was carried out into the rate of photosynthesis under different environmental conditions. The graph shows the results. Which conditions could have produced the results for curve R?

Oct/Nov 2025

Which term describes the release of oxygen by plants?

Oct/Nov 2025

Chlorophyll is present in every organism that carries out photosynthesis. Fig. 4.1 shows mistletoe growing on a tree branch. Most plants contain about 1 mg of chlorophyll in 100 g of their leaves. Mistletoe, however, contains about 0.4 mg of chlorophyll in 100 g of its leaves. Birds attach mistletoe seeds to tree branches. When the seeds germinate, they form special roots that grow into the phloem of the tree branch.

Oct/Nov 2025