18 Questions
Which part of myoglobin binds oxygen reversibly?
Porphyrin ring
What is the role of the His (histidine) residues in myoglobin's structure?
Help prevent conversion of heme iron to Fe3+ state
Which part of myoglobin contains both polar and non-polar amino acids?
Exterior residues
What is the main function of the globin portion in myoglobin?
Facilitate O2 binding to Fe2+ ion
Why does heme iron in myoglobin bind oxygen reversibly?
Due to nitrogen atoms in the porphyrin ring
Which compound binds to heme with higher affinity than oxygen, leading to toxicity?
$CO (carbon monoxide)$
What is the role of His 64 in myoglobin in relation to carbon monoxide binding?
His 64 prevents the linear binding of carbon monoxide to heme iron.
What is the formula for calculating the affinity of a ligand to a protein in terms of dissociation constant (Kd)?
Kd = [P] [L]/[PL]
What does the Oxygen Binding Curve for Myoglobin indicate?
The relationship between oxygen concentration and myoglobin saturation is hyperbolic.
Which factor contributes to the high affinity of hemoglobin for oxygen?
Low P50 value
What structural changes occur in hemoglobin upon oxygen binding?
Transition from R state to T state resulting in conformational stability.
What distinguishes hemoglobin from myoglobin primarily due to quaternary structure differences?
Cooperative binding to small molecules like CO2 and H+
What effect does the rotation and sliding of the ab subunit have on the pocket between the b subunits?
Narrows the pocket
In what state does hemoglobin have a higher affinity for O2?
Oxy-hemoglobin
What is an example of an allosteric effect in hemoglobin?
T R transition
What is the primary characteristic of cooperative binding of oxygen in hemoglobin?
Sigmoid (cooperative) binding curve
Which molecule binds weakly to deoxyhemoglobin as part of the T R transition?
First O2 molecule
What equation is used to describe the binding of oxygen to myoglobin and hemoglobin in Hill plots?
[PLn]/[P][L]n = Ka
Explore the diverse functions of proteins, including structural support, mobility, receptors, ligands, immune response, housekeeping, signaling, storage, transport, and enzymatic activities. Learn about the properties, catalysis, and control of enzymes, as well as the role of myoglobin and hemoglobin in oxygen transport and storage.
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