One way to make the complicated details of DNA structure and function intelligible for children is to compare it to a recipe book. DNA is the master molecule that contains coded instructions for "cooking" the proteins used by living bodies.
DNA is a very large molecule that is built up from smaller molecules known as nucleotides. The exact sequence of these nucleotides, much like the sequence of words in a recipe, tells the living cell how to put organic molecules together to form proteins. Unlike a blueprint, to which DNA is often compared, slight changes to DNA can dramatically affect the end product, making the process dependent on the sequence of steps as in a recipe.