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
What is the genus of the fungus that causes potato blight?
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Answer
The correct genus of the fungus that causes potato blight is Phytophthora. This should be ticked in the answer space provided.
Step 2
How does growing near the surface help the fungus to respire?
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Answer
The fungus benefits by being able to get oxygen from the air when it grows near the surface of the potato. This ensures efficient respiration.
Step 3
What does 'biodiversity in a river' mean?
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Answer
Biodiversity in a river refers to the variety of species of organisms in the river. This encompasses all forms of life within that ecosystem.
Step 4
Explain why the biodiversity in the river decreased.
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Answer
The biodiversity in the river may decrease because the pesticide sprayed on potato plants can wash into the river when it rains. This pesticide kills various organisms, thus reducing the variety of life forms present in the river, including both plant and animal species.
Step 5
Complete Figure 9 to show the possible genotypes of the offspring produced.
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Answer
To complete Figure 9:
For male gametes R and r and female gametes R and r, the offspring genotypes will be:
R
r
R
RR
Rr
r
Rr
rr
Step 6
Draw a ring around one of the homozygous genotypes in Figure 9.
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Answer
In Figure 9, the homozygous genotype RR (or rr) should be encircled, as both are considered homozygous.
Step 7
What percentage of the offspring in Figure 9 will be resistant to potato blight?
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Answer
The percentage of offspring that will be resistant to potato blight is 75%, as three out of the four possible genotypes (RR and Rr) are considered resistant.
Step 8
Explain why.
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Answer
Asexually produced potatoes are genetically identical to the parent plant. Thus, if the parent plant is resistant to potato blight, the new plants will also inherit the same resistance, maintaining this advantageous trait.
