1. Which of the following is NOT a role of histidine in hemoglobin?

The distal histidine occupies the 6th coordination position of Fe2+

2. Why is hemoglobin's affinity for oxygen sensitive to small changes in pH (the Bohr effect)?

Histidine side chains in hemoglobin become charged at lower pH forming salt bridges that stabilize the T state.

3. If hemoglobin is in the 'T' state, what is the first component of the peptide chain that moves in response to oxygen binding?

The proximal histidine

4. If hemoglobin is in the T state, what happens at one -subunit when the other -subunit binds oxygen?

its f-helix moves

5. One of the adaptations to high altitude is an increase in the concentration of BPG in red blood cells. What effect does this have on the oxygen binding curve of hemoglobin and why?

The curve is shifted to the right, because hemoglobin has a lower affinity for oxygen.

6. Which of the following statements most accurately explains why hemoglobin is able to deliver oxygen to myoglobin in the tissues?

Myoglobin has a hyperbolic oxygen binding curve, whereas hemoglobin has a sigmoidal oxygen binding curve.

7. Which of the following statements about hemoglobin is TRUE?

The affinity of fetal hemoglobin for oxygen is higher than that of maternal hemoglobin.

8. Why is BPG essential for the delivery of O2 to the tissues?

BPG stabilizes the T state conformation of hemoglobin.

9. Which of the following is a role of histidine in myoglobin?

A histidine residue forms a hydrogen bond with oxygen.

10. Protein X binds reversibly to ligand Y such that X + YXY, and the molar concentrations of X, Y and XY are known. Which of the following represents the dissociation constant (K) for this reaction?

K = [X][Y]/[XY]