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Question 1
Plants are called producers because they make their own food from a process called photosynthesis. |
a) | Write the balanced symbol equation for photosynthesis.
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b) | Plants need energy to produce glucose. Where do plants get this energy from?
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c) | Which part of a plant cell absorbs the energy needed for photosynthesis?
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d) | Explain why photosynthesis is considered an endothermic reaction.
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e) | Give two uses of the glucose produced in photosynthesis.
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Question 2
In an experiment, a student measures the rate of photosynthesis of a pondweed at different light intensities. The results are shown in the following table. |
a) | Using the data in the table, plot a graph of light intensity against rate of photosynthesis.
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b) | Describe the relationship between light intensity and the rate of photosynthesis.
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c) | At light intensities between 0 and 700 lux, light was a limiting factor for photosynthesis. What evidence is there for this in the table?
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d) | Give one factor that could have limited the rate of photosynthesis when the light intensity was between 800 and 1000 lux.
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e) | The lamp gives out heat as well as light. What could the students do to make sure that heat from the lamp did not affect the rate of photosynthesis?
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Question 3
The diagram below represents a section of a leaf under the microscope, where photosynthesis takes place. |
a) | Identify and describe the role of two structures in the leaf that are involved in photosynthesis.
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b) | In a certain plant species, it is observed that the leaves have fewer stomata than a typical plant. Suggest how this could impact the rate of photosynthesis.
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c) | The plant also has a very thick waxy cuticle. Suggest the environment in which the plant lives and why having fewer stomata and a thick waxy cuticle is a useful adaptation.
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Question 4
A commercial greenhouse grower wants to maximise the rate of photosynthesis to increase the yield of a particular crop. The grower is considering changes in temperature, light intensity, and carbon dioxide concentration within the greenhouse. |
a) | Explain the role of carbon dioxide in photosynthesis and how increasing its concentration might affect the rate of photosynthesis.
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b) | The grower also considers increasing the temperature inside the greenhouse. Explain how temperature can affect the rate of photosynthesis.
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c) | The grower measures the rate of photosynthesis at different temperatures. The results are shown in the table below: Using the data in the table, identify the optimal temperature for photosynthesis in this crop.
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d) | Scientists can collect the volume of oxygen produced by a plant in order to measure the rate of photosynthesis. Why is measuring the amount of oxygen a reliable way to determine the rate of photosynthesis?
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Question 5
Photosynthesis takes place in the leaves of plants. The micrograph below shows the underside of a leaf. |
a) | Label the stoma, guard cells, epidermal cells and chloroplasts.
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b) | Name the gases that:
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c) | Are the stomata larger during the day or at night? Explain your answer.
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d) | Suggest what would happen to the rate of photosynthesis if a plant's stomata get covered in dust.
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Question 6
The figure shows a cross-section of a plant leaf. |
a) | Describe the structure of the leaf and the functions of the tissues in the leaf. Use the names of the tissues in your answer.
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b) | Complete the sentence about photosynthesis. During photosynthesis, dioxide and are converted to glucose and . The energy required for photosynthesis comes from the which is trapped by a green pigment called . The plant can convert the glucose into which is insoluble and can be stored. carbon water oxygen Sun chlorophyll starch
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Question 7
The rate of photosynthesis in a plant depends on several external factors. These factors include light intensity and the availability of water. |
a) | Describe and explain the effects of two other factors that affect the rate of photosynthesis. You should include one or more sketches of graphs in your answer. Model answer
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