Proteins in the cell surface membranes of human cells and mouse cells were labelled with fluorescent dyes. The human cells were labelled with a red dye and the mouse cells were labelled with a green dye. A human cell and a mouse cell were then fused to form a hybrid cell. At first the different dyes remained separate. After 40 minutes the two dyes were evenly distributed in the hybrid cell surface membrane. What explains this observation?
✓ Correct Answer
The correct answer is D: Protein molecules in the outer layer of the cell surface membrane and those which span the bilayer can move freely between phospholipid molecules.
📋 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...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
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