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Describe how fertiliser run-off can cause damage to a lake's ecosystem.

Fertilisers are generally high in nitrogen, to replenish the nitrogen in the soil assimilated by the crop plants. When this is drained into lakes in run-off, it can cause dramatic consequences. Nitrogen avai...
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Answered by William D. • Biology tutor
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How does cholera cause diarrhoea and dehydration?

Cholera is single-celled organism that produces a toxin. The toxin attaches to the ion receptors in the small intestine which causes it to secrete chloride ions into the lumen. This then causes water to move...
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Answered by Madhangi P. • Biology tutor
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What is the difference between DNA transcription and translation?

DNA is used to code proteins. This requires two steps: transcription and translation.Transcription is the conversion of double stranded DNA into a single stranded mRNA molecule. DNA nucleotides bind to their...
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Answered by Rohin A. • Biology tutor
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What is cancer?

For many reasons cell division can become unregulated. This leads to the formation of a mass of cells called a tumour which cannot perform their normal function – they are said to be undifferentiated. In som...
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Answered by Rohin A. • Biology tutor
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In DNA, if you know the percentage of a base on 1 strand, how do you work out the bases on the opposite strand?

This questions requires knowledge of the base pairing in DNA, plus a little bit of maths! As you know, bases on the 2 DNA strands always pair in the same way: A (adenine) with T (thymine) , C (cytosine) with...
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Answered by Eleanor B. • Biology tutor
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