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Plants can be infected by fungi, viruses and insects - AQA - GCSE Biology - Question 5 - 2018 - Paper 1
Question 5
Plants can be infected by fungi, viruses and insects. Aphids are small insects that carry pathogens. Figure 6 shows an aphid feeding from a plant stem. An aphid fe... show full transcript
Worked Solution & Example Answer:Plants can be infected by fungi, viruses and insects - AQA - GCSE Biology - Question 5 - 2018 - Paper 1
Step 1
Give the reason why the mouthpiece of an aphid contains a high concentration of dissolved sugars after feeding.
Answer
The mouthpiece of an aphid has pierced the phloem, as the aphid has been feeding from the phloem. This part of the plant is rich in dissolved sugars, which are essential for the aphid's nutrition.
Step 2
Explain how a deficiency of magnesium could cause these symptoms.
Answer
A deficiency of magnesium in plants can lead to yellow leaves due to lack of chlorophyll. This occurs because magnesium is essential for chlorophyll production. Without enough chlorophyll, the plant is unable to absorb sufficient light for photosynthesis, resulting in a lower rate of energy production. Consequently, this deficiency causes the plant to convert less glucose, leading to stunted growth.
Step 3
Describe how the scientist would use the protein to produce the PVY monoclonal antibody.
Answer
The scientist would inject the PVY protein into a mouse. This process stimulates the mouse's immune system to produce antibodies against the virus. Lymphocytes from the mouse are then extracted and fused with tumor cells to create hybridoma cells that produce a specific monoclonal antibody for PVY. These hybridoma cells can then be cloned to produce many identical cells, resulting in a large quantity of the desired monoclonal antibody.