 The cell nucleus contains the majority of the cell 's genetic material in the form of multiple linear DNA molecules organized into structures called chromosomes . Each human cell contains roughly two meters of DNA . During most of the cell cycle these are organized in a DNA @-@ protein complex known as chromatin , and during cell division the chromatin can be seen to form the well @-@ defined chromosomes familiar from a <unk> . A small fraction of the cell 's genes are located instead in the mitochondria . 
