Answer:
The oxygen dissociation curve for hemoglobin is sigmoidal where as for myoglobin it is hyperbolic.
Step-by-step explanation:
Oxygen dissociation curve: A graphical representation of relationship between partial pressure of O2 and percentage saturation of hemoglobin with oxygen is known as O2-dissociation curve. It is sigmoidal or S- shaped curve. The amount of O2 that can bind with Hb is determined by partial pressure of oxygen. The percentage of Hb that is bound with O2 is called percentage saturation of Hb.
In human adults, at pO2 of 25 mm of Hg the hemoglobin is 50% saturated with oxygen. This partial pressure is called P-50.
Hemoglobin shows S shaped curve due to cooperative binding of oxygen that is binding of first oxygen increases the ability of second oxygen binding and so on. One Hb can carry 4 oxygen molecules.
In case of myglobin, it has more affinity for oxygen but it has only one Fe+2 group, there is no cooperative binding. The curve obtained will be hyperbolic than being sigmoid.
Please find the attached image which shows both the curves. (Image reference: Evolution of Myoglobin and Hemoglobin ; Author and Curator: Larry H. Bernstein, MD, FCAP )
Since myoglobin has more affinity for oxygen its P-50 value is less, that is at low partial pressure of oxygen myoglobin gets 50% saturated. But the P-50 value for hemoglobin is high which means comparatively more partial pressure of O2 is needed for hemoglobin to be 50% saturated.