What does DNA code for in the process of genetic expression?

DNA primarily serves as the blueprint for the synthesis of proteins in a process known as gene expression. The flow of genetic information begins with DNA being transcribed into messenger RNA (mRNA). This is a crucial step because the mRNA carries the genetic instructions from the DNA in the nucleus of the cell to the ribosomes in the cytoplasm, where proteins are synthesized.

While RNA itself is transcribed from DNA, it is not the final product of genetic expression but rather an intermediary that facilitates the manufacture of proteins. Proteins, which are composed of amino acids, carry out a vast array of functions within living organisms including structural, enzymatic, and regulatory roles.

In this context, carbohydrates and lipids are macromolecules that are synthesized through metabolic pathways and are not directly coded by DNA. Through the primary role of DNA in coding for proteins, we see that RNA is essential, but it is not the end product associated with genetic expression itself. Thus, focusing on the ultimate goal of genetic expression helps clarify that proteins are the final products coded for by the DNA.