What DNA Does

           DNA carry all of the information for your physical characteristics, which are fundamentally determined by proteins. So, DNA contains the instructions for making a protein. In DNA, each protein is encoded by a gene (a specific sequence of DNA nucleotides that specify how a single protein is to be made). Specifically, the order of nucleotides within a gene specifies the order and types of amino acids that must be put together to make a protein.  A protein is made of a long chain of chemicals called amino acids.
Proteins have lots of functions :
        Enzymes that over out chemical reactions (such as digestive enzymes)
        Structural proteins that are building materials (such as collagen and nail keratin)
        Transport proteins that over substances (such as oxygen-carrying hemoglobin in blood)
        Contraction proteins that cause muscles to compress (such as actin and myosin)
        Storage proteins that hold on to substances (such as albumin in egg whites and iron-storing ferritin in your spleen)
Hormones - chemical messengers between cells (including insulin, estrogen, testosterone, cortisol, et cetera)
Protective proteins - antibodies of the immune process, clotting proteins in blood
Toxins - poisonous substances, (such as bee venom and snake venom)

The particular sequence of amino acids in the chain is what makes protein different from another. This sequence is encoded in the DNA where gene encodes for protein.