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Question 1
A farmer grows barley in his field. His crop is infected with barley powdery mildew, a type of fungus. |
a) | Suggest two ways the farmer could have used to identify the pathogen infecting the barley crops.
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b) | Describe how fungal infections can spread and how they enter plant leaves.
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c) | The farmer wants to prevent their crops from getting powdery mildew. Explain how burning plants after the barley has been harvested can protect the crops.
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Question 2
Tobacco mosaic virus (TMV) is a disease affecting plants. |
a) | All tools should be washed in disinfectant after using them on plants infected with TMV. Explain why.
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b) | TMV can cause plants to produce less chlorophyll, leading to leaf discoloration. Suggest why plants with TMV have stunted growth.
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Question 3
A rose bush has a disease called rose black spot. |
a) | Give one way to prevent the spread of rose black spot to a different plant in the same area.
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b) | The infected rose bush has yellow leaves and stunted growth. Explain why the rose bush is not growing.
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Question 4
Many plants have evolved defence mechanisms. |
a) | The blackberry plant has evolved to have sharp thorns. What type of defence response are thorns?
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b) | How do the thorns defend the blackberry plant?
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c) | The berries of the honeysuckle plant are poisonous. What type of defence response is this?
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d) | How will the poisonous berries help the honeysuckle plant to survive?
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e) | The leaves of some plants release oils onto their surface. Suggest how the production of oil on the surface of a leaf may protect the plant.
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Question 5
The production of tomatoes can be affected by an insect pest called the tomato leaf miner. The adult female leaf miner lays eggs on tomato leaves that develop into maggots. The maggots feed on leaf mesophyll tissue inside the leaf. |
a) | Explain how the tomato leaf miner affects tomato production.
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b) | A tomato grower suspects his tomatoes have been infected by tomato leaf miner. What can the grower do to ensure he has correctly identified the pest?
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c) | Pheromone traps are sometimes used to control the leaf miner. Pheromones are smells that attract leaf miner males. Design an investigation to assess if a pheromone trap would help to control the leaf miner.
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Question 6
a) | Explain how different types of organism defend themselves against microorganisms.
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Question 7
A gardener is testing the effect of using different fertilisers on the growth of plants. The gardener decided to measure the growth by counting the number of leaves. |
a) | Suggest a better method of measuring the growth of the plants.
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b) | Give two reasons why your method is better than the gardener’s method.
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Question 8
A scientist investigated the effect of nitrate ion concentration on barley growth. She placed barley seedlings in five test tubes containing different concentrations of nitrate fertiliser. |
After a week, the scientist measured the length of the seedlings. Her results were recorded in a table. |
a) | What should the scientist have used as a control for this investigation?
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b) | Which seedling showed the largest change in length?
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c) | Explain how nitrate ions were absorbed by the seedlings.
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