Hemoglobin—The Blood's Oxygen Hunter
Red blood cells carry oxygen to every cell in our body. While the oxygen molecules are flowing freely in blood, the red blood cells need to capture them, with the use of a protein called hemoglobin.
1. Heme Groups
A red blood cell is designed especially for carrying hemoglobin, which takes up 90% of the cell. Organelles like the nucleus and mitochondria, found in other cells, are lacking in red blood cells, leaving room so that their hemoglobin can capture enough oxygen.
Under no circumstances does hemoglobin make contact with oxygen molecule; because if it did, it would oxidize and thus, not allow any oxygen to reach other cells. But under normal circumstances it does not have to come into contact with oxygen as it has been created in a very special manner so as not to face this danger. Instead, it holds the oxygen molecule as if with a pair of tongs.
How does hemoglobin capture oxygen? Hemoglobin protein is composed of four subunits, each containing an iron atom bound to a heme group. These heme groups are the special "tongs" that give hemoglobin the ability to capture oxygen without contact and carry it to the cells that need it. The molecule's torsional angles change in a specific manner during oxygen binding.
Even here, within the tiniest parts of the body invisible to the naked eye, there is a most perfect and faultless harmony. It is impossible for such harmony to have come about as a result of coincidence. The emptying of the red blood cell to make room for hemoglobin, having protein "tongs" to capture oxygen without suffering a chemical reaction, the programming of the hemoglobin molecule to hunt oxygen in the first place, to recognize oxygen molecules and distinguish them from other molecules, the transport of the captured oxygen to where it's needed—none of these is a coincidence. To claim that it is is to cross over the limits of logic and reason. All of these are indications of the infinite knowledge and wisdom of God.