[edit] Definition

DNA is an abbreviation for DeoxyriboNucleic Acid which is the main "blueprint" of a living organism. The DNA molecule is composed of four Nuclear bases called Nucleotides, these are Adenine, Cytosine, Guanine and Thymine, and also a sugar skeleton, DeoxyRibose, which forms the outlying structure of the double helix holding it all together.

[edit] Function

The molecule itself is, relatively speaking, very large and acts as the main repository for "blueprints" = Genes for the various proteins within and outside the cell. The genes are copied into work copies and moved into "production" using mRNA (messenger RNA) in a process that is labeled Transcription.