Physiology Why is the oxygen-hemoglobin dissociation curve sigmoid is shape? A Binding of oxygen to hemoglobin reduces the affinity of Hb for Co2 B Oxygen affinity of Hemoglobin decreases when the pH of blood falls C Binding of one oxygen molecule increases the affinity of binding of other O2 molecules D Binding of one oxygen molecule decrease the affinity of binding other O2 molecules HALDANE EFFECT 💡 Explanation Why is the oxygen-hemoglobin dissociation curve sigmoid is shape? ✓ Correct Answer: C. Binding of one oxygen molecule increases the affinity of binding of other O2 molecules