A-LevelBiologyGas exchange9700/12 · May/June 2019 · Q291 Mark

The diagram shows the pathway for the transport of carbon dioxide that occurs in red blood cells. [Figure: Diagram of CO2 transport pathway] Which row is correct?

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A1: carbaminohaemoglobin, 2: haemoglobinic acid, 3: hydrogen ions, 4: hydrogencarbonate ions

B1: carbonic anhydrase, 2: carbonic acid, 3: hydrogen ions, 4: hydrogencarbonate ions

C1: carboxyhaemoglobin, 2: carbonic anhydrase, 3: carbonic acid, 4: carbon dioxide

D1: haemoglobinic acid, 2: carbonic acid, 3: hydrogencarbonate ions, 4: hydrogen ions

✓ Correct answer

B: 1: carbonic anhydrase, 2: carbonic acid, 3: hydrogen ions, 4: hydrogencarbonate ions

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Topic: Gas exchange, A-Level Biology (syllabus 9700). Multiple choice, 1 mark.
Source: A-Level Biology, May/June 2019 Paper 1 Variant 2, question 29.

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