Breathing and Exchange of Gases — BIOLOGY STD 11 Science — Question
Rajasthan BoardEnglish MediumSTD 11 ScienceBIOLOGYBreathing and Exchange of Gases3 Marks
Question
Define oxygen dissociation curve. Can you suggest any reason for its sigmoidal pattern?
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Answer
The oxygen dissociation curve is a graph obtained when the percentage saturation of haemoglobin with oxygen is plotted against the partial pressure of oxygen.
When the first molecule of oxygen binds to haemoglobin, its affinity for the second molecule of oxygen increases.
Hence, the formation of oxyhaemoglobin is faster which is indicated by the steep slope of the S curve.
When the formation of oxyhaemoglobin comes to rest or when there are no haemoglobin molecules available for binding, the curve achieves a plateau phase.
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