Molecular Evolution and Information

The Information in DNA is Similar to the Four Sided Coin

Life uses a system very similar to the four sided coin, but instead of coins and dictionaries, life uses chemicals. DNA looks like a twisted ladder. The steps of the ladder are composed of four chemicals, adenine, thymine, cytosine and guanine. These four chemicals correspond to the four letters on the four sides of the four sided coin. That is adenine is A, thymine is T, cytosine is C and guanine is G. The one letter abbreviations for these chemicals will be used from now on. The side of the ladder is composed of a chemical called deoxyribose.
    Notice that the steps are A-T, T-A, G-C or C-G, where the dash represents a chemical bond between the chemicals. Adenine always forms a chemical bond with thymine, and guanine always forms a bond with cytosine. A-T is called a base pair as is G-C. There are four possibilities for each step, so each step can hold the same amount of information as the four sided coin or 2 bits.

Figure 3.4: Untwisted DNA Ladder

Figure 3.5: Twisted DNA Ladder



                

next: DNA Replication

home: Intelligent Design & The Origin of Life