What is dna?
DNA is deoxyribonucleic acid, and is hereditary material in humans and almost all other organisms. Nearly every cell in a person's body contains the same DNA. Most DNA is located in the cells nucleus, but a small amount can also be found in the mitochondria, where it is called mitochondrial DNA. DNA consists of genetic information that determines the structure of the cell and the way it functions.
Molecules of DNA are in the form of long strands. The information in DNA is stored as a code, made up of four chemical bases: Adenine (A), Guanine (G), Cytosine (C), and Thymine (T). Human DNA consists of about 3 million bases, and more than 99 percent are very similar or the same in most people. The sequence at which these bases are placed determines the information available for building and maintaining an organism. DNA bases belong in pairs such as: A with T and C with G to form base pairs (units). These bases are likewise attached to a sugar molecule and phosphate molecule.
The sugar and phosphate molecules together form an organic molecule called a nucleotide, they are arranged in two long strands, forming a spiral known as the double helix. DNA is very important in that it can replicate itself. Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of the bases (U.S National Library of Medicine: 29 September, 2014).
The DNA strands are bound to special proteins called histones. Each DNA strand is coiled around the histones so the long molecules of DNA can fit into a small space. In a cell that is not dividing, the coiled DNA forms a tangled network called chromatin (Human Perspectives: 2012). When a cell divides, exact copies of each DNA molecule in the chromatin must be distributed to the daughter cells. Sections of the DNA molecules make up the genes. The genes contain the genetic code, which is the stored information that determines the structure of the cell.
Molecules of DNA are in the form of long strands. The information in DNA is stored as a code, made up of four chemical bases: Adenine (A), Guanine (G), Cytosine (C), and Thymine (T). Human DNA consists of about 3 million bases, and more than 99 percent are very similar or the same in most people. The sequence at which these bases are placed determines the information available for building and maintaining an organism. DNA bases belong in pairs such as: A with T and C with G to form base pairs (units). These bases are likewise attached to a sugar molecule and phosphate molecule.
The sugar and phosphate molecules together form an organic molecule called a nucleotide, they are arranged in two long strands, forming a spiral known as the double helix. DNA is very important in that it can replicate itself. Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of the bases (U.S National Library of Medicine: 29 September, 2014).
The DNA strands are bound to special proteins called histones. Each DNA strand is coiled around the histones so the long molecules of DNA can fit into a small space. In a cell that is not dividing, the coiled DNA forms a tangled network called chromatin (Human Perspectives: 2012). When a cell divides, exact copies of each DNA molecule in the chromatin must be distributed to the daughter cells. Sections of the DNA molecules make up the genes. The genes contain the genetic code, which is the stored information that determines the structure of the cell.