DNA is made up of molecules called nucleotides. Each nucleotide contains a phosphate group, a sugar group and a nitrogen base.
This backbone carries four types of molecules called bases and it is the sequence of these four bases that encodes information. The major function of DNA is to encode the sequence of amino acid residues in proteins, using the genetic code.
It is the DNA that is inherited from parents to the off springs. It contains all the information of an individual on it in the form of genes