The genome is the fundamental amount of genetic code (DNA or RNA) that provides the information necessary to make a particular organism.
In humans, the genome therefore consists of the full set of chromosomes found in a gamete. This information is subsequently doubled (at fertilisation) and copied (at each cell division).
The human genome contains about 30,000 genes, of which we know the functions of about 50%, but, it has been discovered, about 97% of the DNA of chromosomes is actually made up of so-called non-coding regions - not genes, at all. Obviously important, as cells cannot exist without them, the presence of these regions is not yet understood.