Question

A curve representing the binding of oxygen to hemoglobin vs. time is called a Hill plot. Whereas a non-allosterically affected enzymatic reaction displays a hyperbolic curve (v0 vs. [S]), a Hill plot shows a sigmoidal curve. This indicates… A) Cooperativity: oxygen-binding to the first of the four Hb subunits helps the binding to the second and so on. B) Antagonism: oxygen-binding to Hb is counteracted by CO2 in the blood. C) There is something wrong here: the binding of oxygen to Hb shows a hyperbolic function. D) I don’t have enough information to come up with an answer. E) Hill had too much time in his hands.

Answer 1

Answer:

The correct answer is option A.

Explanation:

Hemoglobin refers to a molecule that helps to carry oxygen from the lungs to other tissues of the body. Thus, the molecules of oxygen function as ligands to the hemoglobin. Each molecule of hemoglobin can combine with the four oxygen molecules.  

The binding of one oxygen molecule enhances the affinity of hemoglobin towards binding with another molecule of oxygen. This procedure is known as positive cooperativity.