18 Questions
What is the primary function of the heme group in hemoglobin and myoglobin?
To bind and transport oxygen
How do the structures of myoglobin and hemoglobin differ?
Myoglobin is a monomer while hemoglobin is a tetramer
What is the role of the histidine residue in the binding of oxygen to the heme group?
It stabilizes the binding of oxygen to the iron atom
What is the difference between the T (taut) and R (relaxed) forms of hemoglobin?
The T form is found in deoxygenated blood, while the R form is found in oxygenated blood
What is the primary function of the quaternary structure of hemoglobin?
To regulate the binding of oxygen to the heme groups
How does the binding of oxygen to hemoglobin affect the quaternary structure of the protein?
It causes the two dimers to move further apart
What is the effect of 2,3-BPG binding to deoxyhemoglobin?
Decreases the oxygen affinity of hemoglobin
How does the presence of 2,3-BPG affect the oxygen-dissociation curve of hemoglobin?
Shifts the curve to the right, decreasing oxygen affinity
What is the effect of carbon monoxide (CO) binding to hemoglobin?
Shifts hemoglobin to the R conformation
What is the composition of the heme group in hemoglobin?
A complex organic porphyrin ring structure with a bound iron atom in its ferrous (Fe2+) state
What is the primary function of hemoglobin in the body?
To transport oxygen from the lungs to the tissues
How does the quaternary structure of hemoglobin affect its oxygen-binding properties?
The R conformation has a higher affinity for oxygen than the T conformation
Which form of hemoglobin has a higher affinity for oxygen?
R form
What happens to the polar bonds between the αβ dimers of hemoglobin when oxygen binds?
Some of the polar bonds are ruptured
Which of the following factors can affect the ability of hemoglobin to reversibly bind oxygen?
All of the above
What is the Bohr effect?
The release of oxygen from hemoglobin is enhanced when the pH is lowered or when the hemoglobin is in the presence of an increased pCO2
Which form of hemoglobin is stabilized by the Bohr effect?
T form
What is the significance of the sigmoidal (right) shift in the oxygen-dissociation curve of hemoglobin?
It indicates a lower affinity for oxygen binding
Test your knowledge on the characteristics and functions of hemoglobin and myoglobin, including their affinity to oxygen and the binding process. Learn about the differences in oxygen binding between the R and T forms of hemoglobin.
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