Both myoglobin and hemoglobin exhibit cooperative binding to oxygen. True or False

False.

Explanation:

An Haemoglobin molecule is made up of 4-polypeptides, with each of the polypeptide chain containing an haem group. These haem group can bind with one oxygen atom each.

The binding of the first oxygen atom by the first haem group weakens the tertiary protein structure of Quaternary structure Hb, thus it makes it easier for the second Oxygen atom to bind faster, and the 3rd oxygen very fast and the 4th oxygen atom the fastest. These accelerated binding of the oxygen atoms, facilitated by the first binding O2, is called cooperative binding. It aids oxygen binding capacity and tranport functions of Hb,

Myoglobin is an oxygen storage protein in muscles, and not oxygen carrying molecule, It releases stored O2 only in condition of low oxygen supply. It has one haem group in its molecule. Therefore its structural features can not carry out cooperative binding.