Reference no: EM1385115
1. We are protected to some extent against low level CO poisoning because:
Select one:
a. His F8 on hemoglobin distorts the heme iron atom out of the heme plane and attracts O2, but not CO.
b. Affinity of heme for O2 is much greater than for CO
c. The binding configuration of CO to heme iron favors oxygen binding
d. CO cannot bind to heme in hemoglobin
e. All of the above
2.Which expression is the fraction of oxygen-bound myoglobin in solution (theta, or Y)?
a. pO2/pO2 + p50
b. [Mb][O2]/[MbO2]
c. [Mb]+ [MbO2]
d. [MbO2]/[Mb][O2]
3. When moving towards the lungs, hemoglobin shifts to the ____________ conformation, in which the Kd for oxygen binding is _________.
Select one:
a. R;increased
b. T; lowered
c. R; lowered
d. T; increased
4. The Hills coefficient-
Select one:
a. represent the total number of ligand binding sites in the protein
b. is greater for myoglobin than it is for hemoglob
c. is larger when cooperativity is larger
d. is the difference (delta) in fraction bound (theta, or Y) to hemoglobin between the lungs and capillaries
5. When O2 binds to heme in hemoglobin, the _____ is drawn into the plane of the porphyrin, causing a conformational change that is transmitted to adjacent subunits, ________ the affinity for additional O2 binding.
Select one:
a. Histidine E7; lowering
b. Fe+2 atom; lowering
c. BPG; increasing
d. Fe+2 atom; increasing
e. Histidine E7; increasing
6. The initial trigger for conformational change in hemoglobin, leading to the T/R transition, involves:
Select one:
a. Shift in the porphyrins plane upon oxygen binding, from concave to planar
b. Shift in the relative position of the alpha and beta subunits
c. Dramatic change in the affinity to oxygen in all four binding sites
d. Increase in the blood's BPG concentration
7.In the concerted model for cooperativity, the hemoglobins subunits-
Select one:
a. bind or release oxygen, all at once
b. change T to R or vice versa, all at once
c. bind oxygen in order, first the two alpha subunits, then the two beta subunits
d. show maximum cooperativity when no BPG is present