A-LevelBiologyCell membranes and transportMay/June 2025Paper 1 Q171 Mark
Cell membranes become less fluid as the temperature decreases. Bacteria and yeast cannot regulate their cell temperatures. How do bacteria and yeast maintain the fluidity of their cell membranes when the temperature decreases? 1 They increase the numbers of unsaturated fatty acids in their phospholipid molecules. 2 They increase the numbers of saturated fatty acids in their phospholipid molecules. 3 They increase the numbers of cholesterol molecules in their cell membranes.
A1 and 3
B1 only
C2 and 3
D2 only
✓ Correct Answer
The correct answer is A: 1 and 3
📋 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.
🔒
Unlock the Examiner's Analysis
Sign up for free to reveal the full examiner report, trap analysis, and mark scheme breakdown for this question.
Sign Up Free to Unlock →Join thousands of Cambridge students already using Oracle Prep