The cell faces an issue of location in making protein. While protein is made in the cell's cytoplasm, the information - the DNA - is located in the nucleus. The problem is solved using an intermediate molecule called ribonucleic acid (RNA), specifically a type of RNA called messenger RNA (mRNA). RNA has a structure very similar to DNA, but with three major differences: the sugar is ribose, the base uracil (U) replaces thymine (T), and in most cases RNA has only one strand. The mRNA is formed in a process called transcription, using only one strand (called the "sense" strand) of the DNA as a template. The mRNA is then transported to the cytoplasm where it is read, or "translated," into a protein.

The process of translation requires complex organelles in the cell called ribosomes, and RNA molecules called transfer RNAs (tRNAs). Ribosomes act as scaffolding, holding the mRNA in the correct position so that it can be read by tRNAs, which carry amino acids. In this process, the amino acids are linked together, forming the protein that was originally encoded in the DNA.

This entire process is quickly summed up in the phrase "DNA makes RNA, and RNA makes Protein." This is often referred to as the central dogma of molecular biology.