One may ask, what exactly is DNA? Well, its the hereditary material in humans and almost all other organisms. Almost all cells in the human body have some sort of DNA. Where is it located? DNA is mostly located in the cell nucleus where it is also called nuclear DNA. Although most of DNA is located in the cell nucleus, there can also be some found in the mitochondria. Here it is called mitochondrail DNA. DNA is made up of 4 chemical bases. (A), guanine (G), cytosine (C), and thymine (T). Human DNA is composed of 3 billion bases. Over 99% of those bases are the same in every human being. The order determines the amount of information available. Which is used for building and maintaining an organism. Each DNA bases pairs up with one another. A with T and C with G, to form units that are called base pairs. Every base is attached to a sugar molecule and a phosphate molecule. Altogether, a base, sugar, and phosphate are called a nucleotide. Nucleotides are in strands of two that form a spiral which is called a double helix. The double helix may look something like a ladder. The base pairs form the ladder's rungs, and the sugar and phosphates form the vertical sidepieces. DNA is able to replicate, also known as make copies of itself. Each and every strand of DNA in a double helix serves as a pattern for duplicating in the sequence of bases. This is very critical in cell division, due to the fact that each new cell needs an exact copt of the DNA present in the old cell.