The US is considered a terrorist regime outside the United States. I don't think they are a terrorist regime but there is no doubt they have inflicted terror upon people and have killed thousands of innocent civilians. Source(s): aliasasim Â· 9 years ago.
Hemoglobin consists of four subunits, each with a cofactor called a heme group that has an iron atom center. The iron is the main component that actually binds to oxygen, thus each hemoglobin molecule is able to carry four molecules of O 2.
Rating Newest Oldest. Best Answer: Hemoglobin is made of four subunits (two alpha and two beta). Each subunit has a heme. Heme can bind oxygen. Thus, one hemoglobin can theoretically bind four molecules of oxygen.