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Describe the role of saprobionts in the nitrogen cycle - AQA - A-Level Biology - Question 2 - 2019 - Paper 1
Question 2
Describe the role of saprobionts in the nitrogen cycle. One environmental issue arising from the use of fertilisers is eutrophication. Eutrophication can cause wate... show full transcript
Worked Solution & Example Answer:Describe the role of saprobionts in the nitrogen cycle - AQA - A-Level Biology - Question 2 - 2019 - Paper 1
Step 1
Describe the role of saprobiots in the nitrogen cycle.
Answer
Saprobiots are microorganisms that play a crucial role in the nitrogen cycle by decomposing organic matter, such as dead plant and animal tissues. They utilize enzymes to break down proteins, DNA, RNA, and urea into simpler compounds.
As saprobiots decompose this organic matter, they produce and release ammonia and ammonium ions into the soil, which can be utilized by plants. This process is essential for recycling nitrogen in ecosystems, making it available for use by other organisms.
Step 2
Describe how you would obtain a quantitative measurement of their cloudiness.
Answer
To quantitatively measure the cloudiness of water samples from the three rivers, I would use a colorimeter. The steps are as follows:
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Standardisation of Method: Each water sample should be collected in a clean container to avoid contamination. It is essential to maintain the same sampling method, ensuring consistency across samples.
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Measurement Process: Using a colorimeter, I would measure the absorbance or transmission of light through each water sample. To do this, I would fill the colorimeter cuvette with the water sample and read the absorbance value.
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Control Sample: A zero (blank) sample, consisting of clear water, should be measured to calibrate the colorimeter and set a baseline. The results should be recorded and compared to establish the cloudiness of the river water samples.