The nucleus is the part of the cell that contains most of the genetic information found in cells. Genetic information is stored within a DNA molecule, tightly wound into a structure known as a chromosome. A tiny amount of genetic information is found in the mitochondria, outside of the nucleus.
The DNA molecule is constructed of two backbones that spiral around each other, forming the double helix formation. Bases run along these backbones, while bridges connecting bases are known as base pairs. Human DNA consists of 46 chromosomes in each cell, grouped together in 23 pairs, referenced by their number.