Simple explanation of DNA
DNA (Deoxyribonucleic Acid) is the 'instruction manual' of how to build life. DNA defines everything, from microbes to plants to humans. DNA is what determines your appearence, such as facial features, hair colour and height. It is the basis of inheriance for nearly all organisms. Information is stored in DNA using just four different types of molecules which occur in pairs, there are billions of these pairs and they are organised in a 'double helix' structure that is strong and compact.
Chromosomes, Nuclei, Genes and Proteins
DNA folds into paired packages called Chromosomes. These are stored in the nucleus of the cell. Different species have different numbers of chromosones, humans (both male and female) have 23. Chromosomes contain lots of genes, a gene is a section of DNA that holds the instructions for a protein. Proteins are the building blocks of life, they perform a huge variety of jobs from controlling a cell's functioning to determining the shape of a whole organism.
The strands allow each strand to act as a backup of their other, keeping precious genetic information safe.
A bit of history on the discovery of DNA
James Watson, Frances Crick and Rosalind Franklin played a significant role. Franklin used x-ray diffraction on DNA to find out more about its structure. Watson and Crick used Franklin's data, and other info, to build a model of the structure of DNA.