DNAA. adenineT. thymineC. cytosineG. guanineDNA (d???n-??)n. A nucleic acid that carries the genetic information in cells and some viruses, consisting of two long chains of nucleotides twisted into a double helix and joined by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine. DNA sequences are replicated by the cell prior to cell division and may include genes, intergenic spacers, and regions that bind to regulatory proteins.[d(eoxyribo)n(ucleic) a(cid).]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.DNA n (Biochemistry) deoxyribonucleic acid; a nucleic acid that is the main constituent of the chromosomes of all organisms (except some viruses). The DNA molecule consists of two polynucleotide chains in the form of a double helix, containing phosphate and the sugar deoxyribose and linked by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine. DNA is self-replicating, plays a central role in protein synthesis, and is responsible for the transmission of hereditary characteristics from parents to offspring. See also genetic code abbreviation for did not attend Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014DNA deoxyribonucleic acid: an extremely long, double-stranded nucleic acid molecule arranged as a double helix that is the main constituent of the chromosome and that carries the genes as segments along its strands: found chiefly in the chromatin of cells and in many viruses. [1930?35] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.DNA (d???n-??) Short for deoxyribonucleic acid. The nucleic acid that is the genetic material determining the makeup of all living cells and many viruses. It consists of two strands of nucleotides linked together in a structure resembling a ladder twisted into a spiral. In eukaryotic cells, the DNA is contained mainly in the nucleus and mitochondria. DNA can replicate itself and synthesize RNA. Compare RNA. See Note at gene.Did You Know? One of the wonders of nature is that the complexity and diversity of life can be contained in a molecule with a relatively simple structure. Deoxyribonucleic acid, commonly called DNA, exists mainly in the nucleus and mitochondria of each cell in an organism. It consists of two long strands linked together in a structure resembling a ladder twisted into a spiral, called a double helix. Each rung is made up of two chemical bases, called nucleotides, that are joined together by hydrogen bonds. There are four kinds of nucleotides in a DNA molecule: cytosine, guanine, adenine, and thymine?C, G, A, and T, for short. Specific sequences of these bases, known as genes, form codes that contain all of an organism’s genetic information. When other components of a cell “read” this code, they produce proteins, the building blocks of life.The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.DNAdeoxyribonucleic acid.See also: Heredity-Ologies & -Isms. Copyright 2008 The Gale Group, Inc. All rights reserved.