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A-LevelBiologyCell membranes and transportMay/June 2016Paper 1 Q151 Mark

There is a high concentration of molecule X outside the cell which enters the cell by facilitated diffusion. The results of measuring the concentration of X inside the cell at 30s intervals are shown by the graph. [Figure 15.1] Why does the concentration of X inside the cell remain constant after 150 s? 1 There is no more of X outside the cell. 2 The number of carrier proteins is limiting. 3 There is no net movement of X.

A1 and 2 only
B1 and 3 only
C2 and 3 only
D3 only

✓ Correct Answer

The correct answer is D. This question tests the candidate's understanding of cell membranes and transport within the Biologysyllabus. The examiner's mark scheme requires...

📋 Examiner Report & Trap Analysis

Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...

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About This A-Level Biology Question

This multiple-choice question appeared in the Cambridge A-Level Biology (9700) May/June 2016 examination, Paper 1 Variant 2. It tests the topic of Cell membranes and transport and is worth 1 mark.

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