An organism's entire set of DNA is referred to as its genome. Virtually every single cell inside the frame includes a complete replica of the approximately 3 billion DNA base pairs, or letters, that make up the human genome. With its 4-letter language, DNA includes the records needed to construct the complete human body. A gene historically refers to the unit of DNA that incorporates the instructions for making a selected protein or set of proteins. Each of the anticipated 20,000 to 25,000 genes in the human genome codes for a mean of three proteins. Located on 23 pairs of chromosomes packed into the nucleus of a human cellular, genes direct the production of proteins with the help of enzymes and messenger molecules. Specifically, an enzyme copies the statistics in a gene's DNA right into a molecule known as messenger ribonucleic acid (mRNA). The mRNA travels out of the nucleus and into the cellular's cytoplasm, in which the mRNA is study via a tiny molecular device referred to as a ribosome, and the facts is used to hyperlink collectively small molecules referred to as amino acids in the right order to form a selected protein.