DNA uses a code made up of four letters (actually molecules, ATCG) – we call it Nucleobasis.
If you imagine the ladder they form up the rungs (pairs). Watson-Crick base pair rule: A pairs with T, C pairs with G.
Nucleotide is nucleobase + phosphate + d-sugar.
Biohacking is not just using the technology to hack your body (improve your skills, enhance your abilities). You can hack your body simply by exercising – if you exercise you will hack your body to loose fat and gain muscles.
A good book to read about aging and how to prevent it is Fantastic Voyage: Live Long Enough to Live Forever by Ray Kurzweil and Terry Grossman, M.D. They describe ways how to “live forever” referring to exponential growth of technology and scientific discoveries. It is based on three pillars: old way to prevent aging (consume healthy food and drinks, exercise, etc.), biotechnology and nanobots.
If you don’t want to read the whole book, the authors offer a short guide at http://fantastic-voyage.net/ShortGuide.htm.