Chromosomes in the cell nucleus

DNA exists in a cell's nucleus within structures called chromosomes. Each section of a chromosome that contains the code for the production of a particular protein is called a gene.

A diagram showing the chromosomes and DNA and how they are structures

Each chromosome is made from a single molecule of DNA, but when a cell is ready to divide, the DNA copies itself, then coils and condenses to form the chromosomes that we see under the microscope.

Chromosomes carry genetic information in a molecule called DNA.

Each human body cell contains 46 chromosomes. These can be arranged into 23 pairs.