Which statement below about contrasting Hb and Mb is FALSE?

A. Oxygen binds to a ferrous ion in both proteins.

B. Hb shows cooperativity, whereas Mb does not.

C. Hb binds O2 more tightly than Mb.

D. Hb shows sigmoidal, whereas Mb shows hyperbolic oxygen saturation curves.

E. Hb-oxygen binding is dependent on physiological changes in pH, whereas Mb-oxygen binding is not.

C. Hb binds O2 more tightly than Mb.

Explanation:

Hb and Mb are both oxygen carrier protiens which contain the heme group. Hb has 4 heme units in 1 moleucle which work via coperative effect. On the other hand, Mb has only one heme unit.

From above theory, statement A and B are correct.

Although the heme group of the Mb is identical to those of Hb, Mb has a higher affinity for carrying oxygen than hemoglobin.

Hence, Statement C is wrong.

Thats why the function of hemoglobin is to transport oxygen and that of myoglobin is to store oxygen.

When a curve is plotted between oxygen accepted and the pressure of the oxygen, Hb shows sigmoidal, whereas Mb shows hyperbolic oxygen saturation curves. The statement D is correct.

Bohr effect and various factors decribe the statement : Hb-oxygen binding is dependent on physiological changes in pH, whereas Mb-oxygen binding is not. The statement E is also correct.