Ribosomes inside cells produce and release proteins based on the genetic information in RNA. RNA is a copy of DNA that contains the same genetic information. The DNA remains stored inside the cell nucleus.
When the process begins, the DNA double helix in the cell nucleus unwinds, and RNA binds to it to form a copy. This is called transcription. The only difference between DNA and RNA is that RNA contains the base uracil instead of thymine. Groups of three bases are called codons, and they represent different amino acids.
Strings of amino acids form proteins. Instead of containing genetic information, start and stop codons tell ribosomes where proteins should begin and end. They can also control the production of RNA.
When RNA leaves the nucleus and enters the cytoplasm, it is called messenger RNA or mRNA. It takes its message to a ribosome, a small organelle that assembles amino acids into proteins in a process called translation.
An organelle is a microscopic organ inside a cell. A ribosome can add the correct amino acid to a protein in just a 50th of a second and produce smaller proteins in only a few seconds. When a ribosome reaches a stop codon and the protein is complete, it releases it into the cytoplasm.