Question

The characteristic oxygen binding profile of hemoglobin shown below arises due to the ......... 

• A. quaternary structure
• B. subunit dissociation
• C. cooperativity
• D. conformational change

Hint:

Cooperativity refers to the increased affinity of a protein for a ligand after one ligand binds, as seen in hemoglobin's oxygen binding.

Answer 1

The Correct Option is A, C, D

Step 1: Understanding the hemoglobin binding curve.
The oxygen binding curve of hemoglobin is sigmoidal, which indicates cooperative binding. This means the binding of one oxygen molecule increases the affinity for subsequent oxygen molecules.
Step 2: Analyzing the options.
(A) quaternary structure: Incorrect — While quaternary structure is important, it is the cooperative binding that leads to the sigmoidal curve.
(B) subunit dissociation: Incorrect — The curve is not due to dissociation but due to cooperative binding.
(C) cooperativity: Correct — The cooperative binding of oxygen to hemoglobin produces the characteristic sigmoidal curve.
(D) conformational change: Incorrect — Conformational changes are related to cooperativity, but it is the cooperative binding that is the primary cause.
Step 3: Conclusion.
The correct answer is (C) cooperativity, as it best explains the characteristic binding profile.