Why is DNA called the blueprint of life?
DNA is called the blueprint of life because it contains the instructions needed for an organism to grow, develop, survive and reproduce. DNA does this by controlling protein synthesis. Proteins do most of the work in cells, and are the basic unit of structure and function in the cells of organisms.
To call DNA the Blueprint of Life is an analogy. Blueprints direct the construction of Buildings, DNA directs the " construction" of cells and organisms.
DNA is an informational code that directs the development and function of cells and organisms. Segments of DNA called genes code for the formation of specific proteins. The complex information in the DNA regulates which proteins are made at which time and in what quantity. DNA determines to a large degree what a person will be like.
A blue print is an informational map that directs the construction of a building. The blueprint describes which material is to be used at which points and in what amounts in the construction of a building.
By looking at a blue prints it is possible to determine what the building will look at when it is completed.
The Analogy is not exactly accurate but it provides an idea of what DNA does.