Problem 5
What is the physiological significance of the cooperative binding of oxygen by hemoglobin?
Problem 7
The oxygen-binding behavior of hemoglobin displays aspects of both the sequential model and the concerted model. Explain.
Problem 8
What accounts for the fact that fetal hemoglobin has a higher oxygen affinity than maternal hemoglobin?
Problem 10
Hemoglobin A inhibits the formation of the long fibers of hemoglobin \(S\) and the subsequent sickling of the red cell on deoxygenation. Why does hemoglobin A have this effect?
Problem 11
The first protein to have its structure determined was myoglobin from sperm whales. Propose an explanation for the observation that sperm-whale muscle is a rich source of this protein.
Problem 12
Describe the role of 2,3 -bisphosphoglycerate in the function of hemoglobin.
Problem 13
After a person spends a day or more at high altitude (with an oxygen partial pressure of 75 torr), the concentration of 2,3 -bisphosphoglycerate in that person's red blood cells increases. What effect would an increased concentration of 2,3 -BPG have on the oxygenbinding curve for hemoglobin? Explain why this adaptation would be beneficial for functioning well at high altitude.
Problem 14
Endurance athletes sometimes try an illegal method of blood doping called autologous transfusion. Some blood from the athlete is removed well before competition, and then transfused back into the athlete just before competition. (a) Why might blood transfusion benefit the athlete? (b) With time, stored red blood cells become depleted in 2,3-BPG. What might be the consequences of using such blood for a blood transfusion?
Problem 15
What is the Bohr effect, and what is its chemical basis?
Problem 20
The dissociation constant \(K_{\mathrm{D}}\) for the release of oxygen from oxymyoglobin is \(10^{-6} \mathrm{M},\) where \(K_{\mathrm{D}}\) is defined as $$K_{D}=[\mathrm{Mb}]\left[\mathrm{O}_{2}\right] /\left[\mathrm{MbO}_{2}\right]$$ The rate constant for the combination of \(\mathrm{O}_{2}\) with myoglobin is \(2 \times 10^{7} \mathrm{M}^{-1} \mathrm{s}^{-1}\) (a) What is the rate constant for the dissociation of \(\mathrm{O}_{2}\) from oxymyoglobin? (b) What is the mean duration of the oxymyoglobin complex?
