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GeezerVison is showing www.dictionary.com — DNA Definition & Meaning | Dictionary.com DNAAmerican
DNA
British
noun
abbreviation
DNA
Scientific
/ dē′ĕn-ā′ /
DNA
Cultural
UsageWhat is DNA? DNA is a large, complex molecule that allows cells to function and carries the genetic code that determines the traits of a living organism. DNA is in every cell of every living thing. Some viruses also have DNA. Life as we know it wouldn’t exist without DNA—it contains the instructions that cells need to function. DNA is found in the cell nucleus, and every cell in an organism has the exact same copy of DNA that is in every other cell. Each cell uses its copy of DNA whenever it needs to make a protein. Proteins have many essential jobs within a living thing. For example, your immune system produces proteins called antibodies to fight germs. The information that’s in DNA controls the development of specific traits, such as the shape of a leaf or the color of hair. Specifically, such traits are determined by genes, which are segments of DNA within strands called chromosomes. The set of all information contained in the DNA of any living thing—all of its inheritable traits—is called its genome. DNA is an abbreviation of deoxyribonucleic acid. It is a type of macromolecule (a very large molecule—one composed of hundreds of thousands of atoms) known as a nucleic acid. Nucleic acids are made of smaller molecules known as nucleotides, which are made of a phosphate, a sugar, and nitrogen bases. The four nitrogen bases in DNA are adenine (A), thymine (T), guanine (G), and cytosine (C). DNA has a shape known as a double helix, which resembles a spiraled ladder. The DNA ladder is built from two very long strands of nucleotides with the nitrogen bases pairing together to form the rungs of the ladder. The bases form base pairs, with adenine always paired to thymine and guanine always paired to cytosine. The phosphate and sugar within the nucleotide act as the sides of the ladder. Because DNA only exists within the cell’s nucleus, the genetic information must be distributed somehow. This is one of the roles of RNA, which is a macromolecule that works alongside DNA to make proteins. During this process, RNA acts as a kind of copy of the DNA that carries its genetic information outside of the cell nucleus. We took a microscopic look at the differences between DNA, RNA, and mRNA, and their vital roles. Read all about it here! EtymologyOrigin of DNAFirst recorded in 1930–35; d(eoxyribo)n(ucleic) a(cid) Compare meaningHow does dna compare to similar and commonly confused words? Explore the most common comparisons: Example SentencesExamples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com. See Examples For:
DNA
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