Potato blight is a disease of potato plants - AQA - GCSE Biology - Question 5 - 2021 - Paper 1
Question 5
Potato blight is a disease of potato plants.
Potato blight is caused by the fungus Phytophthora infestans.
1. What is the genus of the fungus that causes potato bli... show full transcript
Worked Solution & Example Answer:Potato blight is a disease of potato plants - AQA - GCSE Biology - Question 5 - 2021 - Paper 1
Step 1
1. What is the genus of the fungus that causes potato blight? Tick (✓) one box.
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Answer
The correct answer is Phytophthora. This genus is well-known for being the causal agent of potato blight, affecting potato crops globally.
Step 2
2. How does growing near the surface help the fungus to respire? Tick (✓) one box.
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Answer
The correct answer is The fungus can get oxygen from the air. Growing near the surface allows the fungus access to atmospheric oxygen, which is essential for its respiration.
Step 3
3. What does ‘biodiversity in a river’ mean? Tick (✓) one box.
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The correct answer is The variety of species of organisms in the river. This encompasses all forms of life within the aquatic environment, including plants, animals, and microorganisms.
Step 4
4. Explain why the biodiversity in the river decreased.
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Answer
The spraying of pesticides can lead to chemicals being washed into the river when it rains. This can be harmful to various species living in the river, as pesticides often kill not only the target pest but also beneficial organisms. Consequently, the death of these organisms will lead to reduced biodiversity, as there will be fewer species present in the ecosystem.
Step 5
5. Complete Figure 9 to show the possible genotypes of the offspring produced.
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Answer
To fill in Figure 9, the genotype combinations are as follows:
Male gametes: Rr
Female gametes: RRR rRr
The complete table will show the genotype combinations of the offspring produced.
Step 6
6. Draw a ring around one of the homozygous genotypes in Figure 9.
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Answer
A ring should be drawn around RR in Figure 9, as it is one of the two homozygous genotypes present.
Step 7
7. What percentage of the offspring in Figure 9 will be resistant to potato blight? Tick (✓) one box.
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The correct answer is 75%. Given the genotypes produced in Figure 9, a majority of the offspring will express the dominant resistance trait.
Step 8
8. Explain why.
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Answer
When potatoes reproduce asexually, the new plants are clones of the parent plant. Therefore, if the parent plant is resistant to potato blight, all its offspring will inherit the same genetic material and traits, making them resistant to the disease as well.
