Final answer:
The shape of an oxygen dissociation curve for hemoglobin (Hb) is sigmoidal, or S-shaped, due to cooperativity. As the partial pressure of oxygen increases, the hemoglobin becomes increasingly saturated with oxygen, allowing for efficient oxygen transportation and delivery in the body.
Step-by-step explanation:
The shape of an oxygen dissociation curve for hemoglobin (Hb) is sigmoidal, or S-shaped. This curve represents the relationship between the partial pressure of oxygen in the blood and the relative Hb-oxygen saturation. As the partial pressure of oxygen increases, the hemoglobin becomes increasingly saturated with oxygen. The S-shaped curve is due to a phenomenon called cooperativity, where the affinity of one heme for oxygen depends on whether other hemes are already bound to oxygen. This allows for efficient oxygen transportation and delivery in the body.