Question

TUUL CUNILL UNSwel. (1 mark each x 18 = 18 marks). 1. The sigmoidal shape of oxygen-binding curve of hemoglobin is due to: Tissues -- -------- Lungs Fractional Saturation Hemoglobin Myo- globin 05 - Pso=26 Oxygen 10 20 30 40 50 60 70 80 90 100 Concentration poz (torr) Figure 4.46 Principles of Biochemistry, 4/ 2006 Pearson Prentice Hall,Inc. It's unique tetrameric quaternary structure. Positive cooperative binding. axd (no 22 B Conformational changes occurs in the hemoglobin protein due to oxygenation. d. Binding of one oxygen molecule to a heme group facilitates binding of oxygen molecule other heme groups of hemoglobin. All of the above.

Answer 1

E. All of the above .

A sigmoid binding curve indicates that a protein exhibits a special binding behaviour. This shape suggests that binding of oxygen at one site with in the heamoglobin tetramer increases the likelihood that oxygen binds at the remaining unoccupied sites. This sort of binding behaviour is reffered to as cooperative,beacuse the binding reaction at individual sites in each haemoglobin molecule are not independent of one another.