Final answer:
The fractional saturation of myoglobin at a pO2 of 2.8 torr would be significantly higher than 50% due to myoglobin's high affinity for oxygen. Without the specific curve, an exact percentage cannot be provided, but it would be approaching full saturation.
Step-by-step explanation:
The student has asked for the fractional saturation of myoglobin at a partial pressure of oxygen (pO2) of 2.8 torr. Myoglobin's oxygen-binding affinity is depicted by its oxygen dissociation curve, which differs from that of hemoglobin, as myoglobin has a higher affinity for oxygen and the curve is hyperbolic rather than sigmoidal. Given that the P1/2 (the pO2 at which half of the myoglobin molecules are oxygen-bound) is about 1 mm Hg, at a pO2 of 2.8 torr, which is higher than the P1/2, we can expect that myoglobin will be significantly more than 50% saturated with oxygen. Without the exact dissociation curve, we cannot provide an exact percentage, but generally, myoglobin will be highly saturated at this pO2 level, approaching its full saturation levels as indicated by its hyperbolic oxygen-binding curve.