CAIE A Level Biology 9700 · Biological molecules
A student is given a sample of a food labelled 'fruit nectar'. They suspect it contains both reducing sugars and the disaccharide sucrose (a non-reducing sugar). They have access to Benedict's solution, dilute hydrochloric acid, sodium hydrogencarbonate, a water bath and a stopwatch. Explain the procedure the student should follow to confirm the presence of both types of sugar, and how the results would be interpreted.
6 marks, so the mark scheme is looking for about 6 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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