Molecular Design Similarities

Doug Lowrie of Austin, Texas, sent me a letter in the fall of 1996 urging me to explore the difference between hemoglobin and chlorophyll, and telling about his own experience. Hemoglobin is the molecule in the blood which accomplishes the transport of oxygen in the human body. That makes it of paramount importance to us as living beings. Chlorophyll is the molecule responsible for converting sunlight into useable energy in plants.

One of the questions that arises in any discussion of molecular structure is what the origin of that structure is. Whether one looks at the structure of the water molecule, of the carbon atom, or of complicated molecules like DNA, the incredible complexities of design seem to suggest an intelligence did the planning, not chance.


In the case of chlorophyll and hemoglobin we have two molecules that are amazingly similar in make up, but which are very different in function. As you look at the two schematic drawings, it is obvious that there is only one major difference in the make up of the molecules and that is that hemoglobin has iron as the central atom in the matrix and chlorophyll has magnesium. In all other respects the molecules are the same.

It is the remarkable chemical characteristics of iron and magnesium which cause the radically different function of these two molecules. The rest of the molecule has an arrangement tailor made to allow the iron and magnesium to express their unique chemistry. Tailoring and arranging molecules and atoms for such specific roles is not something chance can accomplish. At a molecular level it is especially easy to "Know there is a God through the things He has made" (Romans 1:19-21).

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