Paper 3 · 9700/35 Oct/Nov 2025 · 40 marks

Glucose diffusion, fruit sugars, stem xylem: work it, then see the model answer.

Estimate glucose diffusing out of dialysis tubing with Benedict's timings on a dilution series, chart fruit sugars, then plan a stem and measure a vascular bundle. Paper 3 is done at the bench, so this page gives you a realistic set of readings for each experiment. Process them part by part, see how many of the 40 marks you would earn, then compare with a full-mark worked answer.

Past-paper referenceRephrased from Cambridge AS & A Level Biology 9700/35, Oct/Nov 2025 (Paper 3, Advanced Practical Skills), for teaching. The readings, figures, workout and worked answers are ours.

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How Paper 3 is marked

Variables and method

The independent and dependent variables as they apply here, the standardised variables with how each is controlled, a control, and steps someone else could follow.

Results

A table with headings and units, raw readings to a consistent precision, processed values such as rates or percentage changes, means of replicates.

Graphs and conclusions

Axes with labels and units, points plotted accurately, a line or curve that fits the data, and a conclusion that quotes the data.

Drawing and evaluation

Clear, sharp, unshaded drawings in proportion with ruled label lines; sources of error and improvements that fit this investigation; a risk assessment.

Habits that save marks

The questions on this page are rephrased from a Cambridge International past paper for teaching. The readings, figures, wording of the workout and the worked answers are our own; the marking follows the published mark scheme. The original question paper is available from Cambridge.