Early Life, Page 8: [Previous Page] [Next Page] [Class Home Page] Textbook pages 85 - 92

What was the first life like?? Can we ever know?

As we've seen in the previous lectures, we are still quite a long way from seeing evidence of the first life, 'geologically and biologically speaking'. We now turn to geneticists using DNA patterns to give us insight.



DNA - Deoxyribonucleic Acid
A double Helix structure, made up of 4 Bases: Cytosine, Guanine, Thymine, Adenine, known mostly by their first letters C, G, T, and A. C-G make a pair, and T-A make the other pair. When it comes time to reproduce a new cell, the ladder splits down the middle like a zipper. New nucleotides are then attached to the open sites, reproducing an exact match of the parent DNA.



Genetic information about the life form is contained here in the sequencing of the C,T,G and A nucleotides. Something like Morse Code (dots, dashes) or Binary code (0s, 1s), even with this few characters, a lot of information can be stored provided you have a very long sequence!

DNA also drives operation of the Cells, their function and behavior, but does so through reactions with RNA, Ribonucleic Acid. RNA is usually a single template strand made from the DNA.