The Quaternary Structure of Hemoglobin Changes from the T State

Multiple Choice

The quaternary structure of hemoglobin changes from the T state to the R state ________.

A) only after four molecules of O² are bound
B) after the binding of one molecule of O² causes a change in the primary structure
C) when hemoglobin is completely deoxygenated
D) when at least one subunit on each dimeric unit (αβ dimer) is oxygenated