Why is HbF curve to the left of HbA curve in oxygen-dissociation graph?
Fetal Hemoglobin (HbF) has higher affnity towards oxygen as compared to Adult Hemoglobin (HbA) as HbF binds less strongly to BPG (Bis-phosphoglycerate) (BPG reduces oxygen affinity). Hence HbF can carry upto 30 percent more oxygen as compared to HbA. Therefore, oxygen-hemoglobin dissociation curve for HbF will appear on left side.