Biology · Biochemistry

Oxygen binding to myoglobin and hemoglobin can be described by different curves and equations. Curve A represents a hyperbolic binding curve, while Curve B represents a sigmoidal binding curve. Consider the following two reactions: i. E + S ⇌ ES ii. E + nS ⇌ ESn (where S is O2 and E is myoglobin or hemoglobin) The corresponding fractional occupancy (YO2) equations are: I. YO2 = [O2]n / (K + [O2]n) II. YO2 = (pO2)n / (K + (pO2)n), where K = ([E][S]n)/[ESn] III. YO2 = [O2] / (K + [O2]) IV. YO2 = (pO2) / (K + (pO2)), where K = ([E][S])/[ES] Select the option that correctly describes the oxygen-binding features of myoglobin and hemoglobin.