<prompt> Chemical structure of hemoglobin isHas 2 polypeptide chains with 4 hemeHas 4 polypeptide chains with 2 hemeHas 4 polypeptide chains with 4 hemeNone of the above  <response>: Hemoglobin is a protein with a molecular weight of 64,450.Hemoglobin is a globular molecule made up of four subunits . Each subunit contains a heme moiety conjugated to a polypeptide. Ref: Ganongs Review of Medical Physiology Twenty-Third Edition Page No: 523 