A-LevelBiologyGas exchangeMay/June 2023Paper 1 Q331 Mark
The diagram shows some of the events that happen between the plasma and the red blood cells in the circulatory system. [Figure 33.1] What do the numbers 1, 2, 3 and 4 represent?
A1: Cl⁻, 2: HCO₃⁻, 3: H⁺, 4: CO₂
B1: CO₂, 2: HCO₃⁻, 3: H⁺, 4: Cl⁻
C1: HCO₃⁻, 2: Cl⁻, 3: CO₂, 4: H⁺
D1: CO₂, 2: H⁺, 3: HCO₃⁻, 4: Cl⁻
✓ Correct Answer
The correct answer is B: 1: CO₂, 2: HCO₃⁻, 3: H⁺, 4: Cl⁻
📋 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