Some red blood cells contain a molecule called 2,3-bisphosphoglycerate (2,3BPG). If 2,3BPG attaches to haemoglobin, a greater partial pressure of oxygen is required to cause $50\%$ saturation of haemoglobin with oxygen. Which statement correctly describes the effect of 2,3BPG?
- A2,3BPG in red blood cells causes the oxygen dissociation curve to shift to the left.
- BBinding of 2,3BPG to haemoglobin reduces the Bohr effect.
- CThe binding of 2,3BPG to haemoglobin lowers the affinity of the haemoglobin for oxygen.
- DWhen 2,3BPG is absent, oxyhaemoglobin is less likely to unload oxygen.