heme vs. hemoglobin

a deep-red iron-containing blood pigment, C 34 H 32 N 4 O 4 Fe, obtained from hemoglobin.

the oxygen-carrying pigment of red blood cells that gives them their red color and serves to convey oxygen to the tissues: occurs in reduced form deoxyhemoglobin in venous blood and in combination with oxygen oxyhemoglobin in arterial blood. : Hb