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deoxyribonucleic acid

(dee-OK-see-RY-boh-noo-KLAY-ik A-sid)
The molecule inside cells that contains the genetic information needed for a person and most other organisms to develop and grow and is passed from one generation to the next. Deoxyribonucleic acid is made up of two strands that twist into the shape of a spiral ladder called a double helix. Each strand has a backbone that is made up of sugar and phosphate molecules that attach to one of four bases: adenine (A), thymine (T), guanine (G), and cytosine (C). The bases pair up with one another (A with T, and G with C) to form chemical bonds, which act like rungs on a ladder. This holds the two strands of deoxyribonucleic acid together. Also called DNA.
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Structure of DNA; drawing shows a chromosome, nucleosome, histone, gene, and nucleotide base pairs: guanine, cytosine, adenine, and thymine. Also shown is a cell and its nucleus.Enlarge this image in new window
Structure of DNA. Most DNA is found inside the nucleus of a cell, where it forms the chromosomes. Chromosomes have proteins called histones that bind to DNA. DNA has two strands that twist into the shape of a spiral ladder called a helix. DNA is made up of four building blocks called nucleotides: adenine (A), thymine (T), guanine (G), and cytosine (C). The nucleotides attach to each other (A with T, and G with C) to form chemical bonds called base pairs, which connect the two DNA strands. Genes are short pieces of DNA that carry specific genetic information.
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