... from many million nucleotides, in the case of mammalian cells up to 2.5 billion units. This means the sequence of bases is almost infinite, providing an immense store of genetic information. Diagrams showing a) the polymerisation of nucleotides by condensation and b) the formation of a double stranded DNA molecule The code is carried in the information strand of the DNA molecule, the other strand is made from the complimentary bases to the information strand bonded to an identical sugar phosphate backbone and contains no code. The information has to code for 20 amino acids so cannot be made from single bases as it would only code for 4 amino acids, nor can it be from paired bases as it would code for 16 amino acids. Instead the code is made from triplets of bases which have enough combinations to code for 64 amino acids, as the body only needs to manufacture ...

See this essay or coursework document in full right now