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a.
Myoglobin has a higher affinity
for oxygen compared to hemoglobin
Correct! At lower oxygen
concentrations, a much higher fraction of myoglobin would be saturated with oxygen compared to
hemoglobin.
b.
Hemoglobin and myoglobin both have the same affinity for oxygen
c.
Hemoglobin has a higher affinity for oxygen compared to myoglobin
d.
Myoglobin has exactly one-quarter of the affinity for oxygen because it has only one subunit
Hemoglobin is an oxygen transport protein, whereas myoglobin is an oxygen storage protein. They
exhibit different binding curves when plotted on a graph with total partial pressure of the oxygen (x-
axis) plotted against the percentage saturation of hemoglobin (y-axis). Which pattern of binding curves
do these proteins exhibit?
Select one:
a. Myoglobin has a sigmoidal curve whereas the hemoglobin has a hyperbolic curve
b. Both have a sigmoidal binding curve
c.
Hemoglobin has a sigmoidal curve whereas the myoglobin has a hyperbolic curve
Correct!
Myoglobin has a much higher affinity for oxygen with percent saturation increasing rapidly in low
oxygen concentrations; this is demonstrated by a hyperbolic curve. Hemoglobin initially binds to
oxygen at a slower rate at low oxygen concentrations, demonstrated by a sigmoidal curve.
d. Both have a hyperbolic binding curve
Hemoglobin and myoglobin proteins bind to molecular oxygen. However, the protein part of the
hemoglobin does not bind directly to the oxygen. Instead, a specific atom helps bind the oxygen. Which
one of the following will help hemoglobin directly bind to the oxygen?
Select one:
a. Heme
b.
Iron
Correct! Iron is the atom that binds directly with oxygen.
c. Carbon monoxide
d. Histidine
The symptoms of sickle cell anemia are primarily because red blood cells are misshaped. This is due to
.
Select one:
a. a mutation in the alpha hemoglobin gene which leads to the insertion of valine into the
hydrophobic patches on oxygenated hemoglobin.
b.
a
mutation
in
the
beta
hemoglobin
gene
which
leads
to
the
insertion
of
valine
into
the
hydrophobic
patches
on
deoxygenated hemoglobin.
c. a mutation in the beta hemoglobin gene which leads to insertion of glutamate into the hydrophobic
patches on oxygenated hemoglobin. Incorrect.Glutamate is a charged amino acid; its R group will
not interact with a hydrophobic pocket.
d. a mutation in the alpha hemoglobin gene which leads to the insertion of valine into the
hydrophobic patches on deoxygenated hemoglobin.