Francis Crick worked closely with James Watson and together they were able to deduce the structure of the deoxyribonucleic acid (DNA) molecule. This was very important because it showed that DNA, not protein as previously believed, was the actual carrier of genetic instructions for the cell. The Watson and Crick model reveals valuable information about the organization and operation of life itself. Their discovery is generally considered to be the most important scientific breakthrough of this century. Their model, originally constructed in 1953, showed the DNA molecule as consisting of two chains, each wrapped around the same axis like a spiral staircase. These helical chains are made of alternating units of phosphate and sugar molecules. Each side of the chain is connected by four base pairs which include adenine, thymine, guanine, and cytosine. Every base is attached at one end to a sugar molecule. The opposite end of the...