what is a genome

A genome is the complete set of genetic instructions found in an organism. It consists of nucleotide sequences of DNA (or RNA in some viruses) and includes genes and other elements that control the activity of those genes. Each genome contains all the information needed to build that organism and is made up of DNA. The instructions in the genome are made up of DNA, which has a twisted structure in the shape of a double helix. Within DNA is a unique chemical code that guides our growth, development, and health, and this code is determined by the order of the four nucleotide bases that make up DNA: adenine, cytosine, guanine, and thymine (A, C, G, and T for short) . The human genome consists of 23 pairs of chromosomes located in the cells nucleus, as well as a small chromosome in the cell's mitochondria. Almost all eukaryotes have mitochondria and a small mitochondrial genome. The study of the genome is called genomics.